CA2008123C

CA2008123C - Buried pipe making method

Info

Publication number: CA2008123C
Application number: CA002008123A
Authority: CA
Inventors: Marcel Matiere
Original assignee: Individual
Current assignee: Individual
Priority date: 1989-01-20
Filing date: 1990-01-19
Publication date: 1993-06-01
Anticipated expiration: 2010-01-19
Also published as: EP0381547A1; ATE178378T1; FR2642110A1; CA2008123A1; EP0585959A1; EP0585959B1; DE69033036D1; GR3021286T3; DE69027791T2; DE69027791D1; ATE140502T1; FR2642110B1; EP0381547B1; DK0381547T3; ES2091809T3; ES2129477T3

Abstract

The subterranean duct construction system consists of excavating a trench or cutting and laying the duct or tunnel in the bottom of it in the form of prefabricated sections (101 104) for the floor and arched sections (201-206) for the roof. The prefabricated roof and floor sections can be made in a wider variety of shapes, according to the dimensions requjred for the finished duct or tunnel, and they can be made in one or two basic widths, so that a series of roof sections can be used with a series of base sections, giving a wide range of interchangeable sections.

Description

Z00812~

L'invention a pour objet un procédé de réa-lisation d'un conduit enterré par assemblage, sur le site, le long d'un axe longitudinal, d'une pluralité
d'éléments préfabriqués et couvre également les élé-ments préfabriqués et la rna nière dont ils sont pré-sentés.
Il existe différents types de conduits en-terrés réalisés par assemblage d'éléments préfabriqués et constitués notamnent de tronçons tubulaires alignés bout à bout le long d'un axe longitudinal . Chaque tronson tubulaire peut être constitué, par exemple, d'un élément unique de section circulaire . Dans ce cas, les tronçons tubulaires sont généralement munis à
leurs extrémités de parties, respectivement , en sail-lie et en retrait, qui s'emboltent l'une dans l'autreà la pose des éléments et permettent la solidarisa-tion de ces derniers.
Pour une section de passage irnportante, les tronçons de section circulaire ont des poids très élevés et sont difficiles à manipuler,à transporter et mettre en place.
C'est pourquoi, on a également proposé de diviser la paroi du conduit en éléments préfabriqués, chaque tronçon tubulaire étant constitué d'un certain nombre d'éléments s'appuyant les uns sur les autres de façon à constituer une section ferrnée . Souvent, on utilise des éléments d'un seul type couvrant chacun un arc de cercle de longueur donnée et permettant , donc, de réaliser des tronsons à section circulaire . Mais on a aussi proposé d'utiliser des éléments pré-fabriqués de formes différentes permettant de réaliser des tronçons à section non circulaire et, par exemple, présentant un fond plan permettant de mieux répartir sur le sol la charge appliquée.

DA.
1696 EXT.

_ 2 En particulier, le déposant a déjà décrit de telles structures, par exemple dans le brevet européen EP 081.402 qui montre différen-ts modes de réalisation et notam ment un conduit comprenant, en section transversale, quatre éléments,respectivement un élé-ment plan forrnant radier , deux éléments de côtés placés de part et d'autre du radier et munis chacun d'une base leur permettant de se tenir droit sur le sol et un élément de voûte incurvé reposant sur les bords supérieurs des éléments de côté .
Dans un autre mode de réalisation qui fait l'objet du brevet francais n 84 16811 du même dépo-sant, on a décrit un conduit comprenant, en section transversale, seulement deux éléments , respective-ment un élément inférieur formant un radier et un élé-ment supérieur en forme de voûte incurvée en arc de cercle et reposant, par l'intermédiaire de ses deux bords longitudinaux parallèles, sur des organes d'appui rnénagés le long des deux côtés du radier.
Selon l'une des caractéristiques décrites dans le brevet FR 84 16811, les organes d'appui longi-tudinaux ménagés des deux côtés du radier sont consti-tués de rainures à fond creux incurvé dans lesquelles s'engagent les bords longitudinaux de l'élément de voûte qui ont chacun un profil arrondi convexe de courbure légèrement plus marquée que celle de la rai-nure de façon à ménager un léger jeu. Chaque appui longitudinal présente ainsi une certaine possibilité
d'articulation autour d'un axe parallèle à l'axe lon-gitudinal du conduit, chaque élément de voûte pouvant se déformer très légèrement sous la charge transrnise par les terrains qui le surmontent .Celle-ci est transmise aux deux côtés latéraux du radier qui est constitué d'un panneau massif de forme rectangulaire reposant sur le sol par l'intermédiaire d'un fond Z00812 ~

The subject of the invention is a process for reading of a pipe buried by assembly, on the site, along a longitudinal axis, of a plurality of prefabricated elements and also covers the elements prefabricated parts and the re n of which they are pre-smelled.
There are different types of ducts terrés produced by assembling prefabricated elements and consist in particular of aligned tubular sections end to end along a longitudinal axis. Each tubular section can be made, for example, of a single element of circular section. In this case, the tubular sections are generally equipped with their part ends, respectively, in sail-binds and recessed, which embellish one another when the elements are installed and allow the solidarisa-tion of these.
For an important passage section, the circular section sections have very heavy weights high and are difficult to handle, transport and implement.
This is why, we also proposed to divide the wall of the duct into prefabricated elements, each tubular section being made up of a certain number of building on each other's so as to constitute a cross section. We often uses elements of a single type covering each an arc of circle of given length and allowing, therefore, to make sections with circular section . But it has also been proposed to use pre-made of different shapes allowing to realize non-circular sections and, for example, with a flat background allowing better distribution on the ground the load applied.

DA.
1696 EXT.

_ 2 In particular, the applicant has already described such structures, for example in the European patent EP 081.402 which shows different embodiments and in particular a conduit comprising, in section transverse, four elements, respectively one ment plan to write off, two side elements placed on either side of the raft and each provided a base allowing them to stand straight on the floor and a curved arch element resting on the upper edges of the side elements.
In another embodiment which makes the subject of French patent No. 84 16811 of the same filing health, a conduit has been described comprising, in section transverse, only two elements, respective-a lower element forming a raft and an element upper arch in the shape of a curved arch circle and resting, through its two parallel longitudinal edges, on organs support along the two sides of the raft.
According to one of the characteristics described in patent FR 84 16811, the long support members tudinals arranged on both sides of the raft consist of killed by curved hollow bottom grooves in which engage the longitudinal edges of the element of vault which each have a convex rounded profile of curvature slightly more marked than that of the ra-lasts so as to leave a slight play. Each press longitudinal thus presents a certain possibility of articulation around an axis parallel to the axis lon-gitudinal of the duct, each vault element being able to deform very slightly under the transferred load by the terrain that overcomes it.
transmitted to the two lateral sides of the raft which is consisting of a solid rectangular panel resting on the ground via a bottom

2~(~81Z3 -rigide permettant de bien répartir l'ensemble des charges appliquées.
Il est apparu que de telles structures ré-sistent aux charges appliquées de fason active en mobilisant, d'ailleurs, les terrains environnants auxquels une partie de la charge appliquée est transmise par déformation latérale de l'élément supérieur , ce dernier étant ainsi déchargé à la clé .
Ces particularités ont conduit à étendre les possibilités d'application de tels conduits.
En effet, les dispositions décrites dans les brevets préc~dents , notamment EP N081 402 et FR 84 16811 étaient prévues essentiellement pour la réalisation de conduits de très grande section, pouvant même aller jusqu'à des gabarits routiers .Dans ce cas, compte-tenu du coût très important de l'ensemble de l'ouvrage, il est ren-table de déterminer avec précision , en fonction des besoins , les dimensions et les différentes caractéristiques des éléments, de calculer leur résistance, par exemple en appliquant le procédé
décrit dans le brevet EP N 081 402, et de réali-ser des moules spéciaux ou, en tout cas, adapta-2~ bles aux dimensions souhaitées .
On a constaté toutefois que les structuresde ce type présentaient de tels avantages qu'il pouvait être intéressant de réaliser de cette façon des conduits de section moyenne , qui, jusqu'à présent, étaient habituellemetlt consti-tués de tronçons tubulaires de section circulaire.
L'invention a pour objet un nouveau procédé
permettant de mettre à profit les qualités du type de construction décrit notamment dans le brevet FR
84 16811 pour réaliser à la demande et de façon Z00~123 _ 4 particulièrement rapide et économique , des conduits ayant des formes et des dimensions va-riées et dont la constitution et, d'une façon gé-nérale, de nombreuses caractéristiques, , peuvent être déterminées en fonction des besoins avec une grande souplesse d'adaptation.
Le procédé selon l'invention est donc du type dans lequel on réalise un conduit enterré par assemblage sur le site, le long d'un axe longitu-dinal, d'une pluralité d'éléments préfabriqués formant des tronçons adjacents comprenant chacun, en section transversale à l'axe , une partie infé-rieure constituée d'au moins un élément de base et formant un radier reposant sur une surface de pose et une partie supérieure constituée d'au moins un élément formant voûte et reposant sur la partie inférieure par l'intermédiaire d'organes d'appui longitudinaux ménagés respectivement, parallèle-ment à l'axe longitudinal, sur les côtés latéraux de la partie inférieure et de la partie supérieure.
Conformément à l'invention, on détemlline tout d'abord les caractéristiques dimensionnel-les et structurelles d'au moins une série d'éléments de base et d'au moins une série d'éléments supérieurs correspondant à la même lar-geur entre appuis longitudinaux , en faisant va-rier, dans chaque série, au moins un des paramètres de forme et de résistance tels que le profil en section transversale, I'épaisseur et la constitution de l'élément, on associe ensuite, de toutes les manières possibles, des éléments supé-rieurs et des éléments de base compatibles entre eux, de façon à constituer des tronçons types pré-sentant, pour la largeur choisie, des profils, des 200~123 épaisseurs et des constitutions différentes, ond~termine , pour chaque tronçon type ainsi formé, la charge répartie maxirnale admissible par le tronçon type considéré dans diverses conditions d'utilisation, et, pour la réalisation d'un conduit devant présenter une section de passage et un encornbrement donné, et soumis à une charge don-née, on choisit un tronçon type pr~sentant une charge admissible supérieure à la charge devant 10 être appliquée sur le conduit et dont le profil, compte-tenu de la largeur entre appuis, permet de respecter de façon optimale la section de passage et l'encombrement requis et l'on fabrique en nom-bre voulu des éléments de base et supérieurs pré-15 sentant le profil, les dimensions et les caractéristiques structurelles de l'él~ment de la partie inférieure et de la partie sup~rieure du tronçon type choisi, puis l'on construit le conduit par assemblage desdits éléments.
Dans une variante du procéd~, on adjoint aux séries d'éléments de base et d'éléments supé-rieurs, au moins une série supplémentaire d'éléments d'appui formant chacun une semelle iso-lée présentant, sur une face inférieure, une sur-25 face d'assise et, sur une face supérieure, une partie d'appui longitudinale pour un élément supé-rieur et darls laquelle on a fait varier au moins l'une des caractéristiques déterminant la portance et la résistance, telles que la largeur de la sur-30 face d'assise, l'épaisseur, la forme et la consti-tution et , pour réaliser au moins une partie du conduit , on place sur la surface de pose les uns à la suite des autres, deux lignes d'éléments d'appui isolés sur lesquels viennent reposer les ZO(~8123 _ bords inférieurs latéraux des éléments supérieurs, lesdits éléments d'appui isolés étant choisis dans ladite série supplémentaire de façon à être capa-ble de résister aux charges appliquées en service par les éléments supérieurs et à assurer une sur-face d'assise de largeur suffisante, compte tenu desdites charges et de la portance du sol à cet endroit.
De façon particulièrement avantageuse, pour vérifier la charge maximale admissible par chaque tronçon type, on réalise en vraie grandeur les éléments supérieurs et les éléments de base choi-sis dans lesdites séries correspondant respective-ment aux différentes largeurs d'assise, chaque élément d'une série étant réalisé, pour chaque largeur, en un nombre correspondant aux possibili-tés de combinaison avec les éléments d'une autre série et l'on associe par paires les éléments de base et les éléments supérieurs de façon à réali-ser les tronçons types envisagés,puis l'on soumetchaque tronçon type ainsi formé à un essai de cllarge appliquée à la clé jusqu'à la ruine du tronçon pour en déduire, par application de coef-ficients de sécurité , la charge répartie maximale admissible par le tronçon considéré.
D'une façon générale, on réalisera un même nombre (a) de séries d'éléments de base monoblocs et de séries d'éléments supérieurs correspondant à
un même nombre (a) de largeurs entre appui, ce nombre (a) étant déterminé de façon à couvrir, de façon presque continue, grâce au choix du profil, une large gamme de sections de passage permettant de répondre à la demande de la clientèle.

`_ 2~081Z3 L'invention couvre également les éléments pré-fabriqués répartis en plusieurs séries et les profils des tronçolls types réalisés à partir desdits éléments.
Selon une caractéristique avantageuse,pour la détermination des profils en section transversale des éléments de base, on fait varier dans chaque série la hauteur de l'appui longitudinal par rapport au fond de l'élément, chaque appui longitudinal étant ménagé, soit au niveau de la face supérieure du radier, soit 10 à la partie supérieure d'un piédroit s'étendant le long de chaque côté latéral de l'élément de base perpendiculairement au fond et sur une hauteur varia-ble .
Mais on peut aussi, dans une même série 15 d'éléments de base , réaliser des éléments de profils variés présentant diverses caractéristiques utiles telles que , par exernple, des parties en saillie ména-gées sur la face inférieure du fond du radier pour as-surer l'ancrage de celui-ci dans la surface de pose ou 20 bien des évidements tubulaires ménagés dans l'épaisseur du fond parallèlement à l'axe de façon à
r~aliser des canaux internes s'étendant sur toute la longueur de la structure et dans lesquels peuvent pas-ser , par exernple des canalisations électriques ou 25 bien des câbles de précontrainte .
De plus, le fond du radier doit présenter une surface d'appui suffisante pour encaisser la charge supportée mais n'est pas obligatoirement plan et, par exemple, on peut y ménager une cunette axiale faisant 2 ~ (~ 81Z3 -rigid allowing to distribute well all charges applied.
It appeared that such structures withstand applied loads in an active way mobilizing, moreover, the surrounding land to which part of the applied load is transmitted by lateral deformation of the element higher, the latter being thus discharged at the key.
These peculiarities have led to extend the possibilities of application of such conduits.
Indeed, the arrangements described in previous patents, in particular EP N081 402 and FR 84 16811 were mainly planned for the realization of very large conduits section, even up to templates In this case, taking into account the very cost important of the whole work, it is table to determine precisely, depending needs, dimensions and different characteristics of the elements, calculate their resistance, for example by applying the process described in patent EP N 081 402, and of reali-use special molds or, in any case, adapt 2 ~ bles to the desired dimensions.
However, it has been found that such structures have such advantages that could be interesting to realize from this way of medium section conduits, which, so far have usually been consti-killed from tubular sections of circular section.
The subject of the invention is a new process allowing to use the qualities of the type of construction described in particular in the patent FR
84 16811 to perform on demand and in a Z00 ~ 123 _ 4 particularly fast and economical, conduits having wide shapes and dimensions and whose constitution and, in a general way many characteristics, can be determined as needed with a great flexibility of adaptation.
The method according to the invention is therefore type in which a pipe buried by assembly on site, along a longitu-dinal, of a plurality of prefabricated elements forming adjacent sections each comprising, in cross section to the axis, a lower part consisting of at least one basic element and forming a slab resting on a laying surface and an upper part consisting of at least one arch element and resting on the part lower through support bodies longitudinal respectively, parallel-on the longitudinal axis, on the lateral sides of the lower part and of the part superior.
According to the invention, detemlline first of all the dimensional characteristics-the and structural of at least one series basic elements and at least one set higher elements corresponding to the same width gor between longitudinal supports, making laugh, in each series, at least one of shape and resistance parameters such as cross-sectional profile, thickness and constitution of the element, we then associate, all possible ways, superior elements laughers and basic elements compatible between them, so as to constitute standard sections feeling, for the chosen width, profiles, 200 ~ 123 thicknesses and different constitutions, ond ~ terminates, for each typical section thus formed, the maximum permissible distributed load by the typical section considered under various conditions of use, and, for the realization of a duct must have a passage section and a given congestion, and subject to a given charge born, we choose a typical section presenting a admissible load greater than the front load 10 be applied to the duct and whose profile, taking into account the width between supports, allows optimally respect the passage section and the space required and we manufacture in nom-bre wanted basic and superior elements pre-15 feeling the profile, dimensions and structural characteristics of the element lower part and upper part of the chosen standard section, then we build the conducted by assembling said elements.
In a variant of the procedure, we add to the basic and superior element series laughs, at least one more series supporting elements each forming an iso-strip showing, on a lower face, a 25 seat face and, on an upper face, a longitudinal support part for an upper element laughing and darls which we varied at least one of the characteristics determining the lift and resistance, such as the width of the sur-30 seat surface, thickness, shape and structure tution and, to realize at least a part of the duct, place the one after the other, two lines of elements isolated supports on which the ZO (~ 8,123 _ lateral lower edges of the upper elements, said insulated support elements being chosen from said additional series so as to be capa-ble withstand the loads applied in service by the upper elements and to ensure an over-seat surface of sufficient width, taking into account of said loads and of the bearing capacity of the ground at this place.
Particularly advantageously, for check the maximum admissible load by each typical section, we carry out in real size the superior elements and the basic elements chosen located in said respective corresponding series-lying at the different seat widths, each element of a series being produced, for each width, in a number corresponding to the possibilities combination tees with elements of another series and we associate in pairs the elements of base and upper elements so as to reali-ser the standard sections envisaged, then each standard section thus formed is subjected to a test of cllarge applied to the key until the ruin of the section to deduce, by applying coef-safety factors, the maximum distributed load admissible by the section considered.
In general, we will achieve the same number (a) of series of monobloc basic elements and series of higher elements corresponding to the same number (a) of widths between supports, this number (a) being determined to cover, from almost continuously, thanks to the choice of profile, a wide range of passage sections allowing to meet customer demand.

`_ 2 ~ 081Z3 The invention also covers the elements pre-manufactured distributed in several series and profiles typical sections produced from said elements.
According to an advantageous characteristic, for the determination of cross-sectional profiles of basic elements, we vary in each series the height of the longitudinal support in relation to the bottom of the element, each longitudinal support being provided, either at the level of the upper surface of the raft, or 10 at the top of a pedestal extending the along each lateral side of the base element perpendicular to the bottom and over a height varying corn .
But we can also, in the same series 15 basic elements, making profile elements varied with various useful characteristics such as, for example, household projecting parts on the underside of the bottom of the raft for as-secure the anchoring thereof in the laying surface or 20 many tubular recesses made in the thickness of the bottom parallel to the axis so that r ~ realize internal channels extending over the entire length of the structure and in which can-for example, electrical pipes or 25 many prestressing cables.
In addition, the bottom of the raft must have a sufficient support surface to collect the load supported but is not necessarily planar and, for example, we can provide an axial

3~ saillie sur la face inférieure et s'engageant dans un évidement correspondant ménagé dans la surface de pose.
De même, dans chaque série d'éléments de voûte correspondant à une largeur entre appuis déterminée, on peut faire varier la courbure de l'élément et en parti-35 culier le rapport entre la flêche et la largeur entre 20(~8123 appuis; par exemple, on peut réaliser,pour chaque lar-geur entre appuis, des éléments de voûte présentant une courbure demi-circulaire, des éléments surbaissés pré-sentant une courbure en anse de panier et des élé-ments surélevés présentant une courbure ovoide.
Par ailleurs, il est particulièrement avanta-geux de regrouper l'ensemble des caractéristiques des tronçons types, dans un catalogue indiquant les lar-geurs entre appuis des différentes séries d'éléments de 10 radier et de voûte disponibles et, pour chaque largeur entre appuis, les profils des tronçons types avec l'indication de la section de passage et de la charge maximale admissible.
L'invention couvre également une telle présenta 15 tion des possibilités de construction.
En outre, I'invention couvre de nombreuses va-riantes qui seront décrites en détail dans la descrip-tion qui va suivre, en référence aux dessins annexés.
20La figure I représente un premier mode de réalisation d'un conduit à voûte demi-circulaire .
La figure 2 représente un conduit à voûte sur-baissée en anse de panier.
La figure 3 représente un conduit à appuis 25 surélevés .
La figure 4 représente à titre d'exemple deux séries d'éléments pour la mise en oeuvre du procédé .
La figure 5 montre certains exemples de tronçons types réalisables .
30La figure 6 représente schématiquement un es-sai de rupture .
La figure 7 est une vue de côté partielle re-présentant un mode de réalisation particulier de l'appui longitudinal entre un élément supérieur et un 35 élément de radier.

2(~81Z;~
-La figure 8 est une vue de dessus partielle représentant, dans un mode de réalisation particulier, un joint transversal à embo1tement entre deux éléments de radier consécutifs.
La figure 9 représente , en coupe transversale une variante de réalisation d'un conduit selon l'invention .
La figure lO est une coupe longitudinale du conduit de la figure 9 à son extrémité débouchant dans lO un talus .
La figure ll et la figure 12 sont des vues de détail représentant deux modes de réalisation de la liaison entre deux éléments d'appui consécutifs.
La figure 13 représente, à titre d'exemple, 15 deux séries lll, Ill' d'éléments d'appui.
La figure l4 est une vue en coupe transversale d'un autre mode de réalisation.
La figure l5 est une vue schématique,en pers-pective, du conduit de la figure l4.
Sur la figure l , on a représenté en section transversale à l'axe , un premier exemple de tronçon de conduit constitué de deux types d'éléments , respecti-vement un élément de base l formant un radier posé sur le sol et un élément supérieur 2 en forme de voûte in-25 curvée reposant sur l'élément de radier l. Les éléments l et 2 sont réalisés par moulage , normalement en béton armé ou précontraint, ou bien en béton de fibres mais d'autres matières moulables peuvent être utilisées .
Le conduit est placé dans le fond d'une tran-30 chée B qui est ouverte jusqu'à une surface de poseaplanie et tassée A placée au niveau voulu, le conduit étant, après la pose, recouvert d'un remblai C. Le conduit ainsi enterré est donc soumis d'une part à la charge du remblai qui dépend essentiellement de la hau-teur de ce dernier et, d'autre part, à des charges 2~812;~

d'exploitation appliquées, par exemple, sur une chaus-sée D aménagée sur le remblai.
L'élément de base 1 comprend un fond 10 constitué d'un panneau massif en béton armé de forme rectangulaire muni, le long de ses deux côtés latéraux 11, de deux appuis longitudinaux qui, dans l'exemple représenté, sont constitués par des rainures à fond in-curvé 72 placées sensiblement au niveau de la face su-périeure du fond 10.
L'élément de voûte 2 a une forme cylindrique en plein cintre, centrée sur un axe longitudinal (O) , qui peut être placé soit dans le plan horizontal des rainures 72, soit à une hauteur h au-dessus de la face supérieure 13 du radier I . Par exemple, dans le mode 15 de réalisation de la figure I , I'élément de voûte 2 est muni de deux cotés plans 21 tangents à la partie circulaire 20 qui permettent de surélever l'axe O de la même hauteur.
En conservant la forme en plein cintre de la 20 voûte , il est ainsi possible de faire varier la hau-teur totale H du conduit en modifiant la hauteur des parties planes 21 de l'élément de voûte 1.
Chaque extrémité 22 de l'élément supérieur 2 de voûte est munie d'un bord arrondi convexe 71 qui 25 s'er-gage dans la rainure concave 72 correspondante au niveau de la face supérieure 12 de l'élément de base 1.
Le bord arrondi 71 a une courbure un peu plus accentuée que celle de la rainure 72 de façon à ménager un léger jeu permettant aux parties inférieures 25 de l'élément 30 de voûte de pivoter très légèrement de part et d'autre du plan vertical P passant par le fond de chaque rainu-re 72. On constitue ainsi, sur chaque côté latéral, un organe d'appui 7 articulé autour d'un axe parallèle à
l'axe (O) du conduit.

20(~81Z3 De ce fait, comme on l'a décrit dans le bre-vet FR 84 16811, I'élément de voûte 2 peut se déformer très légèrement, grâce à ses appuis articulés 7,7',sous l'action des charges appliquées et il en résulte une certaine diminution des contraintes à la clé, une par-tie de la cl~arge étant reprise latéralement par le rem-blai 32.
Chaque appui articulé 7 doit cependant être maintenu latéralement . A cet effet, chaque rainure 72 est limitée par des bords relevés 14 qui, dans le cas représenté sur la figure 1, où les rainures sont pla-cées au niveau de la face supérieure 13 du radier, ont une hauteur ne dépassant pas 5 cm , ce qui permet de réaliser, les bords relevés 14 à la coulée du béton sans utiliser de moule particulier. Les éléments de ra-dier 13 peuvent donc être moulés rapidement et économi-quement .
Il est possible également, comme on l'a dé-crit dans le brevet FR 84 16811 d'appliquer les bords 22 de la voûte dans les rainures 72 au moyen de tirants 25 mis sous tension en prenant appui sur des parties 24 de la voûte un joint d'étanchéité étant interposé entre les bords 71, et le fond des rainures 72.
En faisant varier la hauteur h des parties inférieures planes 21 de l'élément de voûte, on peut modifier la hauteur totale H de la structure ainsi que la section de passage S à l'intérieur du conduit.
Mais pour une même largeur entre appuis, on peut aussi réduire la hauteur H du conduit en donnant à
la voûte une forme surbaissée en anse de panier, comme on l'a représenté sur la figure 2. Bien entendu, dans ce cas, la section de passage S est aussi réduite . Si l'on doit respecter une hauteur maximale, on pourra augmenter la largeur du radier et par conséquent la distance entre appuis L de facon à assurer une section de passage déterminée.

2008~23 En outre, sans modifier le profil de la voû-te, on peut aussi augmenter la section de passage S du conduit en utilisant, cornme on l'a représenté sur la figure 3, un élément de radier en forme de caisson cornprenant, le long des deux côtés latéraux, deux pié-droits 15 s'étendant verticalement sur une hauteur va-riable hl. Un tel mode de réalisation permet de surélever le niveau des appuis longitudinaux 7 par rapport au fond 13 et conviendra,par exemple lorsque, 10 le conduit sert au passage d'une hauteur d'eau ne dé-passant pas, en service normal, la hauteur des appuis 7. Une telle disposition perrnet de maintenir hors de l'eau les appuis longitudinaux tant que le débit trans-porté par le conduit est normal, un débit supérieur, 15 par exemple en cas de crue, étant pris en charge par la totalité du conduit qui peut être mis sous pression si la voûte 2 est reliée au radier I par les tirants 25 et s'appuie sur des joints d'étanchéité.
Les figures 1,2 et 3 montrent donc comment 20 I'on peut choisir les dimensions et le profil des élé-ments préfabriqués pour faire varier la section de pas-sage et l'encombrement, en particulier la largeur L et la hauteur H du conduit , en fonction des circonstances , notamment les conditions d'utilisation 25 et le site de construction.
En particulier, les caractéristiques dimen-sionnelles et structurelles des éléments tels que l'épaisseur de la voûte, la nature du béton et la cons-titution du ferraillage devront être déterminées en 30 fonction des contraintes appliquées par le remblai et par les charges d'exploitation.
Mais d'autres caractéristiques pourraient également être modifiées ou ajoutées, selon les be-solns.

2()0812;~

Par exemple, sur les figures I , 2 et 3, on a représenté trois types de radiers . Sur la figure 1, les organes d'appui 7 sont placés sensiblement au ni-veau de la face supérieure 13 de l'élément de base 1.
Sur la figure 2, au contraire, les organes d'appui 7 sont légèrement surélevCs et placés à la partie supé-rieure de piédroits 15 dont la face interne 15' est ar-rondie de facon à faciliter l'écoulement du liquide transporté et ~ éviter les dépôts.
10Sur la figure 35 les piédroits 15 sont encore surélevés et l'élément de base I a une forme en cais-son ou coque de section rectangulaire, l'élément supé-rieur 2 ayant une forrne en plein cintre. Mais on pourrait aussi donner à l'élément supérieur 2 la même 15 forme en caisson, comme on l'a représenté sur l'exemple 205 de la figure 4 , I'ensemble du conduit ayant alors une section rectangulaire.
Certains accessoires peuvent également être ajoutés aux éléments de base ou aux éléments supé-20 rieurs.
Ainsi, sur la figure 1, on a représenté un élément de base I présentant un fond plan 15 qui permet la pose sur une surface A simplement aplanie et tas-sée.
25Sur la figure 2, on a représenté un autre exemple d'élément de base 1 dont le fond 10 est - muni,dans sa partie centrale , d'une cunette 17 ménagée dans l'axe et faisant saillie sur la face inférieure 16 Dans ce cas, la surface de pose A est munie d'un évi-30 dement Al de section correspondant à celle de la cunet-te, les deux parties de la face inférieure 16 placées de part et d'autre de la cunette 17 devant évidemment avoir une largeur suffisante pour la transmission au sol des efforts appliqués.

On a déjà indiqué, en se référant à la figure 3 , que l'élément de base 1 peut être muni sur ses cô-tés de piédroits 15 permettant de surélever d'une hau-teur variable les appuis longitudinaux 7 . Sur cette figure, on a également représenté , à titre d'exemple, un fond 16 sur lequel ont été ménagées des parties en saillie 18 qui forment des aspérités permettant d'ancrer le radier 1 dans le sol, par exemple pour s'opposer à des effets de ripage latéral.
Les éléments de voûte 2 peuvent également fai-re l'objet de variantes dont certaines ont déjà été
décrites.
On peut donc ainsi déterminer à l'avance dif-férentes formes d'éléments supérieurs 2 et d'éléments 15 de base 1 qui peuvent être combinés de toutes les façons possibles.
Par ailleurs, pour chaque profil, on peut aussi faire varier les paramètres déterminant la résis-tance du béton, comme l'épaisseur de la voûte, la natu-20 re du béton employé et la constitution du ferraillage,les armatures pouvant d'ailleurs être précontraintes.
A cet égard, il peut également être interes-sant, comme on l'a représenté sur la figure I , de mé-nager dans l'épaisseur des éléments de base I des 25 évidements tubulaires 19 qui se placent dans l'alignement les uns des autres à la pose des éléments I de façon à former des canaux longitudinaux dans les-quels on peut faire passer des armatures de pré-contrainte solidarisées ensuite, de façon classique, en 30 coulant un mortier.
De tels canaux 19 pourront aussi être utili-sés par exemple pour le passage de canalisat ions ou de câbles électriques ou téléplloniques.
De façon avantageuse, on peut aussi, comme on 35 l'a représenté schématiquement sur la figure g, ménager _ 15 le long des deux bords transversaux 8 de chaque élément de base I des parties en saillie 81 qui s'engagent dans des parties en retrait 82 ménagées sur le bord trans-versal en regard de l'élément de radier 1' adjacent.
De la sorte, on assure un centrage relatif des éléments consécutifs perrnettant d'~viter les risques de désalignement , lorsque la structure est soumise à un effet de ripage latéral, par exemple dans des courbes.
Un effet de ripage longitudinal peut égale-ment appara1tre , par exemple lorsque la structure est réalisée sur une surface inclinée par rapport à
l'horizontale .
Dans ce cas , comme on l'a représenté en vue de côté sur la figure 7, chaque organe d'appui longitu-dinal 7 présente un profil en créneau . La partie pro-: filée convexe 71 ménagée sur chaque bord inférieur 22 de l'élétnent supérieur 2 s'étend en effet alternative-ment sur deux niveaux différents de façon à comprendre, par exemple, une partie centrale en saillie 71 encadrée par deux parties en retrait 73 qui s'engagent dans des parties inversées rn~nagées en creux 74 et en saillie 75 sur le bord supérieur de l'élément de radier 1 et qui sont munies d'une rainure longitudinale 72.
Un tel profil en créneau permet d'assurer le maintien longitudinal de chaque élément supérieur 2 par rapport à l'élément de base I correspondant .
~ien entendu, d'autres dispositions analo-gues, comprenant des parties en creux et en saillie dé-calées longitudinalement, pourraient être utilisées.
On a ainsi été amené à définir les caracté-ristiques d'un certain nombre de profils d'éléments su-périeurs et d'éléments de base qui, cornme on l'a représenté sur la figure 4 , peuvent être classés en séries correspondant chacune à une largeur entre appui.

2()08~23 La première série I d'éléments de base I com-prend donc un certain nombre d'éléments de même largeur entre appuis Ll mais ayant des profils, des dimensions, des ferraillages , etc..différents.
A titre d'exemple, sur la figure 4, la série I d'éléments de base comprend un élément 101 dans le-quel les organes d'appui 4 sont dans le plan de la face supérieure 13 du radier et un ou plusieurs éléments 102, 103 dans lequel les organes d'appui 4 sont ménagés 10 à la partie supérieure de piédroits 15 dont la hauteur hl, mais aussi la forme, peuvent varier. Par exemple, I'élément 104 est muni de faces internes 105 incurvées de façon à se raccorder tangentiellement au fond .
Par ailleurs, ces éléments de base peuvent 15 également être munis d'organes accessoires tels que, des conduits longitudinaux 19 ou bien des crans 18 d'ancrage ménagés sur la face inférieure 16 du radier.
De tels accessoires ont été représentés à titre d'exemple sur l'élément 104 mais pourraient être ména-20 gés sur les autres éléments.
De la même façon, la série 11 d'éléments su-périeurs 2 pourra comporter,par exemple, un élément 202 surbaissé en anse de panier, un élément 203 surélevé
sur des parois latérales planes, un élément 204 suré-25 levé de forme ovoide, un élément 205 en coque rectangu-laire , un élément 206 en forme de dalle , etc...
D'autres caractéristiques comme l'épaisseur e, la nature du béton ou le ferraillage peuvent varier.
Par exemple, on peut réaliser des éléments ayant un 30 ferraillage en une ou deux nappes ou bien des éléments en béton arm~ de fibres ou en une autre matière moula-ble et résistante.
Pour une autre distance entre appuis L2, on réalisera une seconde série 1' d'éléments de base dans 35 lesquels on fait varier un certain nombre de caracté-20~8123 _ 17 ristiques telles que le profil, la hauteur des appuislongitudinaux par rapport au fond, I'épaisseur, etc..
et une seconde série 11', d'éléments de voûte ayant des profils, des épaisseurs ou des ferraillages différer-ts.
On peut définir ainsi les caractéristiques d'un certain nombre (a) de série I d'éléments de base et 1I d'éléments supérieurs, chaque série correspondant à une largeur entre appuis, de façon ~ couvrir de façon aussi continue que possible mais dans des conditions économiquement rentables, une large gamme de sections de passage permettant de répondre aux besoins de la clientèle . En pratique on pourra , par exemple définir quatre séries d'éléments de base et d'éléments supé-rieurs dont les largeurs s'échelonnent entre 1 m et2,50 m ce qui permet,selon le profil adopté, de réali-ser des surfaces de passage depuis 0,35 m2 jusqu'à 6 m2 , environ.
Les éléments supérieurs et de base ainsi dé-ZO finis sont tous réalisés en vraie grandeur et en nombresuffisant pour pouvoir être associés deux à deux de toutes les façons possibles et souhaitables, en formant un certain nombre de tronçons types de même largeur et dont les profils et la section de passage sont sensi-blement différents.
Bien entendu, les éléments associés devrontêtre compatibles et, par exemple, on associera ensemble des éléments de voûte et des éléments de base ayant des épaisseurs et des ferraillages leur permettant de sup-porter des efforts du même ordre.
On réalise ainsi, pour chaque largeur entreappuis, différents tronçons types Tl,T2, T3.... corres-pondant à des hauteurs, des sections de passage et des résistances différentes et dont certains ont ét~ repré-sentés, à titre d'exemple , sur la figure 5.

Ayant défini les caractéristiques dimension-nelles des éléments dont on pourra disposer, il est possible d'en calculer le ferraillage et la résistance en appliquant des méthodes de calcul connues. Cepen-dant, selon l'une des particularités de l'invention, onpréférera, dans certains cas, vérifier la résistance des éléments en soumettant chaque tronçon type ainsi formé à un essai de rupture dans une installation sché-matisée sur la figure 6 par une presse P, tout autre 10 système pouvant être utilisé dans la mesure où il per-met d'appliquer à la clé 23 de l'élément de voûte 2 un effort vertical d'intensité variable.
Pour chaque tronçon type , on augmente pro-gressivement la charge appliquée à la clé 23 jusqu'à la 1~ ruine de l'élément.On détermine ainsi la charge de rup-ture du tronçon type considéré.
Or, pour un profil et une épaisseur de voûte donnés, il est possible de calculer le rapport entre les momerlts fléchissants résultant de l'application 20 d'une charge ponctuelle à la clé et d'une charge répar-tie sur la largeur de l'élément.
On peut donc déterminer, à partir de la char-ge ponctuelle ayant entralné la rupture, la charge ré-partie qui aurait eu la même conséquence et, en 25 appliquant un coefficient de pondération facile à défi-nir entre la sollicitation de service et la sollicita-tion de rupture,on détermine la charge maxirnale admissible en service pour le tronçon type soumis à
l'essai.
Bien entendu, toutes les caractéristiques, profil de courbure, épaisseur, ferraillage, etc... des deux éléments de chaque tronçon ont été notées .
On soumet ainsi à ur- essai de rupture tous les troncons Tl~T2... qu'il est possible de constituer, 3~ pour chaque largeur entre appuis, à partir des éléments des deux séries I d'éléments de base et 1I d'éléments supérieurs et l'on peut dresser un tableau indiquant pour chaque largeur entre appuis et pour chaque tronçon expéritnental la section de passage S et la charge maxi-male admissible.
Sur ce tableau, on peut ajouter également d'autres caractéristiques permettant de définir chaque élément , par exemple son épaisseur, un dessin du pro-fil etc..
Tous ces renseignements sont avantageusement regroupés dans un catalogue montrant d'une part les profils de tous les tronsons types que l'on peut réali-ser et qui ont été soumis à un essai de rupture et don-nant d'autre part, sous forme de tableau, l'ensemble des caractéristiques utiles et, par exemple, des réfé-rences permettant de retrouver, pour un tronçon typedéterrniné, toutes les caractéristiques des éléments qui le constituent.
Un tel catalogue peut être présenté au client qui définit tout d'abord ses besoins et les conditions d'utilisation, en particulier la section de passage S
souhaitée , l'encombrement en largeur L et en hauteur H
que l'on doit respecter et, bien entendu, les caracté-ristiques du site de construction notamment la hauteur de remblai Hl au-dessus du conduit.
On détermine alors, en fonction de la hauteur et de la nature du remblai et des charges d'exploitation, la charge maximale qui sera appliquée en service sur le conduit , ainsi que la largeur entre appuis permettant de répondre au mieux aux conditions d'encombrement à respecter et l'on indique quels sont , dans le catalogue,les différents tronçons types corres-pondant à une charge admissible supérieure à la charge de service précédemment calculée et permettant d'assurer, dans les meilleures conditions, la section de passage voulue. Le client choisit alors le tronçon 20(~8123 ! _ type perrnettant de répondre, de façon optirnale,à
l'ensemble de ses besoins.
On peut disposer en stock d'un certain nombre d'éléments de plusieurs largeurs présentant des caractéristiques sensiblement différentes en ce qui concerne le profil, les épaisseurs et le ferraillage et correspondant aux besoins les plus courants .Si les éléments nécessaires se trouvent en stock , ils peuvent immédiatement être livrés sur le chantier .
Si les élémer-ts nécessaires ne se trouvent pas en stock , ils peuvent cependant être réalisés très rapidement car toutes leurs caractéristiques di-mensionnelles et structurelles sont déjà définies et on dispose , normalement, des moules qui ont servi à la 15 réalisation des éléments soumis aux essais préalables .Lorsque le client commande des éléments présentant d'autres caractéristiques accessoires, comme des cana-lisations internes ou des organes d'ancrage, ou bien de légères variations de dimensions dues à des exigences 20 d'implantation, Otl adapte simplement le moule pour l'obtention, à la coulée , de ces caractéristiques supplé mentaires , toutes les autres caractéristiques restant bien fixées .
On réalise alors en nombre voulu les éléments 25 préfabriqués soit dans une usine soit sur le cllantier et on les assemble pour construire le conduit.
Dans les modes de réalisation décrits jusqu'à
présent, la partie inférieure 1 était constituée d'éléments préfabriqués monoblocs formant un radier 30 continu . Il est possible, cependant, de remplacer cha-que élément de base 1 par deux éléments d'appui espacés 30 de façon à constituer deux lignes d'appui 3 séparées par un espace libre.

Une telle disposition, qui a été repré-sentée sur les Figures 9 et l0, pourra1t être uti-le, par exemple, pour de très grandes sections pour lesquelles des éléments de base monoblocs de-viendraient intransportables. En effet, les élé-ments d'appui 30 forment des semelles isolées dont la largeur peut être prévue pour ménager une sur-face d'appui suffisante. En particulier, dans le cas de sols présentant une bonne résistance, la largeur de la semelle 32 pourra1t être réduite.
De tels éléments, qui sont identiques et peuvent être empilés facilement, sont moins lourds et moins encombrants que des éléments monoblocs couvrant toute la largeur du conduit.
Dans le mode de réalisation représenté
sur les Figures 9 et l0, chaque élément supérieur 20 a la forme d'une voûte incurvée reposant sur les éléments d'appui 30 par ses bords latéraux in-férieurs, ces derniers ayant un profil arrondi convexe et s'insérant chacun dans une rainure 31 en forme de goulotte concave ménagée sur la face supérieure de chaque élément d'appui 20. On réali-se ainsi deux organes d'appui longitudinaux pré-sentant une certaine possibilité d'articulation de l'élément supérieur 20 par rapport aux deux élé-ments d'appui 30.
Comme on l'a déjà décrit pour les éléments supérieurs 2 et les éléments de base l, il est pos-sible de réaliser au moins une s~rie III d'éléments d'appui ~ l'intérieur de laquelle on fait varier un certain nombre de caractéristiques dimension-nelles et structurelles comme, par exemple, la largeur de la surface d'assise, la hauteur de l'élément, la forme des organes d'appui 31, la na-ture du béton employé et la constitution du fer-_, raillage, etc... .
A titre d'exemple, sur la Figure 13, ona représenté schématiquement deux séries III, III' d'éléments d'appui correspondant chacune à une largeur L'l et L'2 de la surface d'assise et dans lesquelle on a fait varier les formes des élé-ments.
En plus des séries, 1, 1'.... d'éléments de base 1 et 11, Il'.... d'éléments supérieurs 2, iO on dispose ainsi d'au moins une série supplémen-taire 111 d'éléments de base et, selon les besoins, on pourra donc associer les éléments de voûte 20 choisis dans la série correspondante, soit à des éléments de radier correspondant à la même largeur entre appuis, soit à des éléments d'appui isolés choisis dans une série supplémentaire 111, 111' présentant une surface d'assise compatible avec la portance du sol.
Le remplacement d'un élément inférieur monobloc par deux ~léments d'appui séparés ne change pas sensiblement la charge maximale admis-sible car celle-ci dépend essentiellement de la résistance de la voûte, le rôle du radier étant essentiellement de transmettre au sol la charge appliquée sur la voûte et d'assurer une étanchéité
vers le bas.
L'espace existant entre les deux élé-ments d'appui séparés 30 pourra, selon le cas être laissé libre ou bien fermé de toute facon adéquate correspondant à l'utilisation du conduit.
Sur la Figure 9, par exemple, la partie inférieure 4 du conduit est constituée d'une cou-che de base 41 en agrégats compact~s, placée entre les côtés lat~raux internes 33 des éléments d'appui 30 et recouverte d'une dalle 42 qui peut -être constituée d'éléments préfabriqués ou bien coulée en place en recouvrant les faces supérieu-res 34 des éléments d'appui 30.
On peut ainsi, comme on l'a représenté
sur la Figure 10, faire passer entre les deux li-gnes d'appui 3 une chaussée 43 et l'on voit que l'un des avantages de cette disposition réside dans le fait que la chaussée 43 peut être réalisée sans discontinuité et de façon classique à l'inté-rieur comme à l'extérieur du conduit alors que deséléments inférieurs en béton irnposeraient un rac-cordement avec la chauss~e ext~rieure avec les risques de décalage dûs aux tassements différen-tiels et aux dilatations.
Par ailleurs, les plans des joints transversaux 23 entre deux éléments de voûte 20 consécutifs peuvent être décalés longitudinalement par rapport au plan des joints transversaux 35 en-tre les éléments d'appui 30. De la sorte, la char-ge appliquée par chaque élément supérieur 20 se répartit sur deux éléments d'appui consécutifs, de part et d'autre du plan de joint.
Les joints transversaux entre deux élé-ments 30 consécutifs peuvent être réalisés de dif-f~rentes façons.
Sur la Figure 11, par exemple, on a re-présenté un joint scellé 5 entre deux éléments consécutifs 30, 30'. Ces derniers sont munis, sur leurs faces frontales en vis à vis, d'armatures en attente 51 qui s'entrecroisent dans un espace 50 laissé entre les deux éléments 30 et 30' et qui sont associés à des fers transversaux 52, l'ensemble étant noyé dans un mortier de scelle-ment 53. Le joint de scellement 5 ainsi réalisé
entre les deux éléments consécutifs 30 et 30' constitue un véritable clavage dans le sens longi-tudinal. ~n solidarisant ainsi un certain nombre d'éléments consécutifs, on réalise, sur une lon-gueur déterminée, une longrine monobloc qui permet de répartir la charge sur le sol et d'éviter les tassements différentiels.
Mais il est aussi possible, comrne on l'a représenté sur la Figure 4, de placer aux extrémi-tés en vis à vis de deux éléments consécutifs 30 et 30', des orgar-es de liaison 54, 54' qui s'emboîtent l'un dans l'autre et peuvent être re-liés par une broche 5~. Les deux éléments consé-cutifs 30 et 30' sont ainsi reliés entre eux par une liaison articulée donnant à cl-aque élément une i5 légère possibilité de déviation par rapport aux éléments qui l'encadrent.
~ ien entendu, les dimensions des élé-ments d'appui 30 et notamment la largeur L' de leur surface d'assise et leur hauteur H' seront choisies en fonction des circonstances d'utilisation, et notamment des charges supportées et de la capacité de portance du sol.
Différents profils pourront également être prévus. Par exemple, pour la réalisation de chaussées souterraines, au moins l'une des lignes d'appui 3 pourra1t être constituée d'éléments 30 conformés de façon à présenter une face supérieure 34' sensiblement horizontale et placée au-dessus du niveau de la chaussée 4 de façon à réaliser un trottoir de circulation de piétons.
D'autres accessoires préfabriqués pour-raient d'ailleurs être avantageusement ajoutés à
la série d'éléments d'appui 30.
Par exemple, le côté interne des élé-ments 30 pourralt être muni de parties aménagées Z0~312~

pour constituer ou recevoir des rails de circula-tion d'un chariot ou portique facilitant le monta-ge et/ou l'entretien de l'ouvrage.
Selon une autre variante représentée sur les Figures 14 et 15, le conduit est prévu pour le passage de liquide, par exemple d'une rivière.
Dans ce cas, le fond 6 du conduit peut être avantageusement constitué d'une série de plaques 61 en fonte, en tôle ou en matière plastique, ayant une largeur égale à celle du conduit et re-couvrant l'espace entre les deux éléments 30, en remontant sur les faces supérieures 34 de ceux-ci, jusqu'au-dessus des joints 31. Comme indiqué sur la figure, les plaques 61 peuvent limiter un pro-fil en creux, par exemple pour le passage d'un ca-nal et la hauteur H' des éléments d'appui 30 peut être augmentée de façon à élever le niveau des joints 31 jusqu'au-dessus du niveau moyen de l'eau, le fond 6 limitant ainsi une section suffisante pour les débits moyens. Des joints d'étanchéité peuvent être placés entre les parties supérieures 31 des éléments d'appui 30 et les bords supérieurs 62 de chaque plaque 6 de façon à
permettre au niveau de l'eau de monter au-dessus du niveau des bords 62 en remplissant plus ou moins le conduit, en cas de crue. Le conduit peut même être mis sous pression si les bords infé-rieurs 21 de la voûte 2 sont appliqués dans le fond des rainures 31 par des tirants mis sous ten-sion.
De plus, comme on l'a représenté sur lavue en perspective de la Figure 6, les plaques 61 peuvent avantageusement se recouvrir mutuellement ~ la façon d'un entuilage, I'extrémité transversa-le 63 d'une plaque tournée vers l'aval, dans le -sens de circulation du liquide, recouvrant I 'extrémité avant 64 de la plaque suivante 69, avec interpos i t ion d' un cordon d' étanchéi té .
D'autres modes de revêtement du fond pourra1ent évidemment être employé. Il est possi-ble dans cer tains cas, que I 'axe longi tudinal lO
du conduit soit incliné par rapport à
I 'horizontale et les éléments d'appui 30 peuvent alors avoir tendance à riper. Pour l'éviter, il sera intéressant de prévoi r sur les faces infé-rieures 32 des éléments 30, des crans d'accrochage 37 qui peuvent être réal isés au bétonnage ou bien, comrne on l 'a représenté sur la Figure 6, être mé-nagés sur une plaque en fonte 3~ scel lée sur la face inférieure de chaque élément d'appui 30.
Comme indiqué sur la Figure 15, en cas de forte déclivité, les faces d'assise 16 des élé-ments de base l ou 32 des éléments d' appui 30 pour-raient former des gradins, la surface de pose A
constituant des marches de largeurs correspondantes.
Pour éviter tout danger de ripage, les éléments 30 peuvent être ancrés dans le sol par des poutres transversales formant clavettes. I l en est de même des éléments supérieurs 2 qui peuvent être clavetés par rapport aux éléments de base l.
Selon une autre disposition avantageuse représentée sur les Figures lO et 15, on ad joint aux éléments supérieurs 2 des pièces de tête 9 placées à chaque extrémi té du condui t .
En effet, le conduit est enterré sous un remblai C et débouche à chaque extrémi té dans un talus C' qui doi t être maintenu par les deux côtés latéraux. Pour éviter de prolonger inuti lement le conduit à l'extérieur du remblai C, on utilisera avantageusement des pièces de tête comprenant cha-cune une paroi verticale 9 de forme triangulaire ou t r apézo i da l e, as soc i ée à une s eme l I e 90 .

, _ Sur les Figures 2 et 6, par exemple, la semelle 90 est constituée d'un ou plusieurs éléments d'appui 39 identiques à ceux 30 qui sup-portent les éléments de voûte 20. Chaque pièce de t~te est alors constituée d'une plaque 9 compre-nant un coté horizontal 91 qui repose sur la par-tie supérieure 31 de l'élément d'appui 39 correspondant, un côté vertical 92 placé dans le prolongement du côté 24 du dernier élément supé-rieur 25 du conduit, et un coté incliné 93 dontl'inclinaison correspond à l'angle naturel du ta-lus C'.
Le maintien de la paroi 9 peut etre as-suré par un scellement réalis~ entre les côtés verticaux 92 et 24 en vis à vis ou bien par embo1-tement de pièces adéquates scellées dans les faces en regard desdits cotés 91, 24.
De plus, la paroi 9 prend appui, dans le sens longitudinal, sur une butée 37 fermant la goulotte 31 dans laquelle s'engage le coté hori-zontal 91.
Mais on pourrait aussi réaliser des piè-ces de tete munie chacune d'une semelle 90 faisant corps avec la paroi verticale 9, de façon à réali-ser un élément autostable.
Par conséquent, on pourra encore ajouter aux séries III, III' d'éléments supérieur et infé-rieur, une série de pièces de tete présentant des épaisseurs, des hauteurs et, éventuellement, des inclinaisons diff~rentes de façon à pouvoir s'adapter aux différents cas de la meilleure façon.
D'une façon générale d'ailleurs, on pourra1t imaginer d'autres variantes et d'autres dispositions accessoires, par exemple pour réali-ser différemment le fond ou la partie supérieuredu conduit. 3 ~ protrusion on the underside and engaging in a corresponding recess in the installation surface.
Likewise, in each series of arch elements corresponding to a determined width between supports, we can vary the curvature of the element and in part 35 show the relationship between the arrow and the width between 20 (~ 8123 supports; for example, for each lar-geur between supports, arch elements having a semi-circular curvature, pre-lowered elements feeling a curvature in the basket handle and elements raised elements with an ovoid curvature.
In addition, it is particularly advantageous to geux to group together all the characteristics of standard sections, in a catalog indicating the geurs between supports of different series of elements of 10 raft and arch available and, for each width between supports, the profiles of the standard sections with the indication of the passage section and the load maximum allowable.
The invention also covers such a presenta 15 tion of construction possibilities.
In addition, the invention covers many which will be described in detail in the description tion which follows, with reference to the accompanying drawings.
20Figure I represents a first mode of realization of a semicircular arch duct.
FIG. 2 represents a vaulted duct over-lowered in basket handle.
Figure 3 shows a support duct 25 raised.
Figure 4 shows by way of example two series of elements for implementing the method.
Figure 5 shows some examples of standard sections achievable.
30 Figure 6 schematically shows an es-break point.
Figure 7 is a partial side view re-presenting a particular embodiment of the longitudinal support between an upper element and a 35 element to write off.

2 (~ 81Z; ~
-Figure 8 is a partial top view representing, in a particular embodiment, a cross joint with interlocking between two elements to write off consecutive.
Figure 9 shows, in cross section an alternative embodiment of a conduit according to the invention.
Figure 10 is a longitudinal section of the Figure 9 conduit at its end opening into lO an embankment.
Figure 11 and Figure 12 are views of detail representing two embodiments of the connection between two consecutive support elements.
FIG. 13 represents, by way of example, 15 two series III, Ill 'of supporting elements.
Figure 14 is a cross-sectional view of another embodiment.
Figure 15 is a schematic view, in pers-pective, from the duct of figure l4.
In Figure l, there is shown in section transverse to the axis, a first example of a section of duct made up of two types of elements, a basic element l forming a raft placed on the floor and an upper element 2 in the form of an arch 25 curved resting on the element to write off l. The elements l and 2 are made by molding, normally in concrete reinforced or prestressed, or in fiber concrete but other moldable materials can be used.
The duct is placed at the bottom of a tran 30 chée B which is open to a leveled and packed surface A placed at the desired level, the conduit being, after installation, covered with fill C.
conduit thus buried is therefore subject on the one hand to the load of the embankment which depends mainly on the height the latter and, on the other hand, charges 2 ~ 812; ~

applied, for example, on a shoe sée D fitted out on the embankment.
The basic element 1 comprises a bottom 10 consisting of a solid shaped reinforced concrete panel rectangular provided, along its two lateral sides 11, of two longitudinal supports which, in the example shown, are formed by grooves with a bottom curved 72 placed substantially at the level of the surface bottom 10.
Arch element 2 has a cylindrical shape semicircular, centered on a longitudinal axis (O), which can be placed either in the horizontal plane of grooves 72, i.e. at a height h above the face upper 13 of the raft I. For example, in the mode 15 of the embodiment of FIG. I, the arch element 2 has two planar sides 21 tangent to the part circular 20 which allow the O axis to be raised the same height.
Keeping the semicircular shape of the 20 arch, it is thus possible to vary the height total height H of the duct by modifying the height of the flat parts 21 of the roof element 1.
Each end 22 of the upper element 2 of the vault is provided with a rounded convex edge 71 which 25 fits into the concave groove 72 corresponding to the level of the upper face 12 of the base element 1.
The rounded edge 71 has a slightly more pronounced curvature than that of groove 72 so as to provide a slight clearance allowing the lower parts 25 of the element 30 of arch to pivot very slightly on both sides from the vertical plane P passing through the bottom of each groove re 72. One thus constitutes, on each lateral side, a support member 7 articulated around an axis parallel to the axis (O) of the conduit.

20 (~ 81Z3 Therefore, as described in the short-vet FR 84 16811, the arch element 2 can deform very slightly, thanks to its articulated supports 7,7 ', under the action of the applied loads and this results in a some reduction of the constraints to the key, a par-tie of the key ~ arge being taken laterally by the rem-blai 32.
Each articulated support 7 must however be held laterally. For this purpose, each groove 72 is limited by raised edges 14 which, in the case shown in Figure 1, where the grooves are placed created at the level of the upper face 13 of the raft, have a height not exceeding 5 cm, which allows realize, raised edges 14 when pouring concrete without using a special mold. The elements of ra-dier 13 can therefore be molded quickly and economi-only.
It is also possible, as has been said written in patent FR 84 16811 to apply the edges 22 of the vault in the grooves 72 by means of tie rods 25 energized by pressing on parts 24 of the arch a seal being interposed between the edges 71, and the bottom of the grooves 72.
By varying the height h of the parts lower planes 21 of the arch element, one can modify the total height H of the structure as well as the passage section S inside the duct.
But for the same width between supports, we can also reduce the height H of the duct by giving the arch a lowered shape like a basket handle, like it has been shown in Figure 2. Of course, in in this case, the passage section S is also reduced. Yes we must respect a maximum height, we can increase the width of the raft and therefore the distance between supports L so as to ensure a cross-section of determined passage.

2008 ~ 23 In addition, without changing the profile of the vo-te, we can also increase the passage section S of the driven using, as we have shown on the Figure 3, a raft element in the form of a box including, along the two lateral sides, two feet straight 15 extending vertically over a height riable hl. Such an embodiment allows raise the level of the longitudinal supports 7 by relative to the bottom 13 and will be suitable, for example when, 10 the conduit is used for the passage of a height of water which does not not passing, in normal service, the height of the supports 7. Such a provision allows keeping out of water the longitudinal supports as long as the flow carried by the duct is normal, a higher flow rate, 15 for example in the event of a flood, being supported by the entire duct which can be pressurized if the roof 2 is connected to the raft I by the tie rods 25 and relies on seals.
Figures 1,2 and 3 therefore show how 20 we can choose the dimensions and the profile of the elements prefabricated elements to vary the cross-section wise and the bulk, especially the width L and the height H of the duct, depending on the circumstances, including conditions of use 25 and the construction site.
In particular, the dimen-structural and structural elements such as the thickness of the vault, the nature of the concrete and the consistency Titration of reinforcement should be determined in 30 depending on the constraints applied by the embankment and by operating expenses.
But other characteristics could also be modified or added, as required solns.

2 () 0812; ~

For example, in Figures I, 2 and 3, we have depicted three types of rafts. In Figure 1, the support members 7 are placed substantially at the level calf of the upper face 13 of the base element 1.
In FIG. 2, on the contrary, the support members 7 are slightly raised and placed at the top upper side 15 of which the internal face 15 'is rear rounded to facilitate the flow of liquid transported and ~ avoid deposits.
10 In Figure 35 the side walls 15 are still raised and the basic element I has a box shape sound or shell of rectangular section, the upper element laughing 2 having a semicircular shape. House could also give upper element 2 the same 15 box shape, as shown in the example 205 of Figure 4, the entire duct then having a rectangular section.
Some accessories may also be added to the basic elements or to the superior elements 20 laughers.
Thus, in Figure 1, there is shown a basic element I having a flat bottom 15 which allows laying on a surface A simply leveled and heaped sée.
25Figure 2 shows another example of basic element 1 whose bottom 10 is - provided, in its central part, with a recess 17 provided in the axis and projecting from the underside 16 In this case, the installation surface A is provided with a 30 dement al of section corresponding to that of the cunet-te, the two parts of the underside 16 placed on both sides of the cunette 17 in front of course have sufficient width for transmission to applied stress.

We have already indicated, with reference to the figure 3, that the basic element 1 can be provided on its sides 15 corner tees to raise from a height variable tor longitudinal support 7. On this figure, there is also shown, by way of example, a bottom 16 on which were arranged parts in projection 18 which form asperities allowing to anchor the raft 1 in the ground, for example to oppose lateral shifting effects.
The roof elements 2 can also be re subject to variants some of which have already been described.
We can thus determine in advance different ferent forms of upper elements 2 and elements 15 basic 1 which can be combined from all possible ways.
In addition, for each profile, we can also vary the parameters determining the resistance concrete strength, such as the thickness of the vault, the nature 20 re of the concrete used and the constitution of the reinforcement, the reinforcements being able moreover to be prestressed.
In this regard, it can also be interes-sant, as shown in Figure I, of me-swim in the thickness of the basic elements I of 25 tubular recesses 19 which are placed in alignment of each other when installing the elements I so as to form longitudinal channels in the-which we can pass pre-constraint then joined together, in a conventional manner, in 30 pouring a mortar.
Such channels 19 can also be used.
for example for the passage of channeling ions or electric or teleplonic cables.
Advantageously, we can also, as we 35 has shown schematically in Figure g, household _ 15 along the two transverse edges 8 of each element basic I of the projecting parts 81 which engage in recessed portions 82 formed on the trans-versal opposite the adjacent to write off element 1 ′.
In this way, we ensure a relative centering of the consecutive elements to avoid the risks of misalignment, when the structure is subjected to lateral shifting effect, for example in curves.
A longitudinal shifting effect can also appear, for example when the structure is performed on a surface inclined to the horizontal.
In this case, as shown in view from the side in FIG. 7, each support member longitu-dinal 7 has a niche profile. The pro-: convex thread 71 formed on each lower edge 22 of the upper element 2 indeed extends alternately-lie on two different levels in order to understand, for example, a central projecting part 71 framed by two withdrawing parties 73 who engage in inverted parts rn ~ swum recessed 74 and projecting 75 on the upper edge of the raft element 1 and which are provided with a longitudinal groove 72.
Such a niche profile ensures the longitudinal support of each upper element 2 by relative to the corresponding basic element I.
~ ien heard, other analogous provisions gues, comprising recessed and projecting parts aligned longitudinally, could be used.
We were thus led to define the characteristics of a certain number of profiles of su-periors and basic elements which, as we have shown in Figure 4, can be classified as series each corresponding to a width between support.

2 () 08 ~ 23 The first series I of basic elements I com-therefore takes a certain number of elements of the same width between supports Ll but having profiles, dimensions, different types of reinforcement.
For example, in Figure 4, the series I of basic elements includes an element 101 in the-which support members 4 are in the plane of the face upper 13 of the raft and one or more elements 102, 103 in which the support members 4 are arranged 10 at the top of the corners 15 whose height hl, but also the shape, can vary. For example, Element 104 is provided with curved internal faces 105 so as to connect tangentially to the bottom.
In addition, these basic elements can 15 also be provided with accessory organs such as, longitudinal ducts 19 or notches 18 anchor formed on the underside 16 of the raft.
Such accessories have been shown as example on element 104 but could be 20 aged on the other elements.
Similarly, the 11 series of elements periors 2 could include, for example, an element 202 lowered into basket handle, a raised element 203 on flat side walls, an element 204 over-25 ovoid shaped, element 205 in rectangular shell laire, an element 206 in the form of a slab, etc ...
Other characteristics such as thickness e, the nature of the concrete or the reinforcement may vary.
For example, elements with a 30 reinforcement in one or two layers or elements in reinforced concrete with fibers or in another molded material ble and resistant.
For another distance between supports L2, we will realize a second series 1 'of basic elements in 35 which are varied a number of characteristics 20 ~ 8123 _ 17 such as the profile, the height of the longitudinal supports in relation to the bottom, the thickness, etc.
and a second series 11 ′, of arch elements having profiles, thicknesses or reinforcements differ-ts.
We can thus define the characteristics of a certain number (a) of series I of basic elements and 1I of upper elements, each corresponding series at a width between supports, so ~ cover so as continuous as possible but under conditions economically profitable, a wide range of sections to meet the needs of the customer base . In practice we can, for example define four sets of basic and superior elements laughers whose widths range between 1 m and 2.50 m which allows, depending on the profile adopted, to serve passage areas from 0.35 m2 to 6 m2, about.
The upper and basic elements thus Finished ZOs are all made in real size and in sufficient numbers to be able to be associated two by two of all possible and desirable ways, by training a certain number of standard sections of the same width and whose profiles and passage section are sensitive quite different.
Of course, the associated elements must be compatible and, for example, we will associate together arch elements and basic elements having thicknesses and reinforcements allowing them to sup-carry similar efforts.
One thus realizes, for each width between supports, different sections Tl, T2, T3 .... corres-laying at heights, passage sections and different resistances and some of which have been ~ represented-shown, for example, in FIG. 5.

Having defined the dimension-of the elements that will be available, it is possible to calculate the reinforcement and the resistance by applying known calculation methods. However dant, according to one of the features of the invention, one will prefer, in certain cases, to check the resistance elements by submitting each typical section as well trained in a rupture test in a dry installation materialized in FIG. 6 by a press P, any other 10 system that can be used as long as it puts to apply to the key 23 of the arch element 2 a vertical force of variable intensity.
For each typical section, we increase gressively the load applied to the key 23 until the 1 ~ ruin of the element. This determines the load of rup-ture of the typical section considered.
However, for a profile and a thickness of arch given, it is possible to calculate the ratio between the bending momerlts resulting from the application 20 of a one-off charge with the key and a repairable charge tie across the width of the element.
We can therefore determine, from the char-punctual age having caused the rupture, the load party that would have had the same consequence and, in 25 applying an easy-to-define weighting coefficient between service solicitation and solicitation failure, we determine the maximum load admissible in service for the standard section subject to the test.
Of course, all the features, profile of curvature, thickness, reinforcement, etc ...
two elements of each section were noted.
All of the sections Tl ~ T2 ... which it is possible to constitute, 3 ~ for each width between supports, from the elements of the two series I of basic elements and 1I of elements superiors and we can draw up a table indicating for each width between supports and for each section experientnental the passage section S and the maximum load admissible male.
On this table, we can also add other characteristics to define each element, for example its thickness, a drawing of the pro-wire etc ...
All this information is advantageously gathered in a catalog showing on the one hand the profiles of all the typical sections that can be ser and which have been subjected to a rupture test and give on the other hand, in tabular form, the whole useful features and, for example, references references allowing to find, for a typical section, all the characteristics of the elements which constitute it.
Such a catalog can be presented to the customer who first defines his needs and conditions of use, in particular the passage section S
desired, the overall width L and height H
that must be respected and, of course, the characteristics construction site including height of backfill Hl above the duct.
We then determine, depending on the height and the nature of the embankment and the loads the maximum load that will be applied in service on the duct, as well as the width between supports to best meet the conditions of space to be respected and we indicate which are, in the catalog, the different standard sections correspond laying on an admissible load greater than the load of service previously calculated and allowing to ensure, in the best conditions, the section of passage wanted. The customer then chooses the section 20 (~ 8123 ! _ type allowing to respond, optirnally, to all of his needs.
We can have in stock a certain number elements of several widths presenting significantly different characteristics with regard to concerns the profile, thicknesses and reinforcement and corresponding to the most common needs.
necessary items are in stock, they can immediately be delivered to the site.
If the necessary elements are not found not in stock, they can however be made very quickly because all their characteristics and structural are already defined and we normally has the molds that were used for 15 realization of elements subjected to preliminary tests When the customer orders items with other accessory features, such as internal connections or anchors, or slight variations in dimensions due to requirements 20 of implantation, Otl simply adapts the mold to obtaining, at casting, these characteristics all other features remaining well fixed.
The elements are then produced in a desired number 25 prefabricated either in a factory or on the planter and we put them together to build the conduit.
In the embodiments described up to present, the lower part 1 consisted one-piece prefabricated elements forming a slab 30 continuous. It is possible, however, to replace each as basic element 1 by two spaced support elements 30 so as to constitute two separate support lines 3 by a free space.

Such a provision, which has been represented felt in Figures 9 and 10, can be used the, for example, for very large sections for which one-piece basic elements of-would come untransportable. Indeed, the ele-support elements 30 form insulated footings, the width can be provided to spare an over-sufficient support face. In particular, in the in the case of soils with good resistance, the width of the sole 32 can be reduced.
Such elements, which are identical and can be stacked easily, are lighter and less bulky than monobloc elements covering the entire width of the duct.
In the embodiment shown in Figures 9 and 10, each top element 20 has the shape of a curved arch resting on the support elements 30 by its lateral edges lower, the latter having a rounded profile convex and each fitting into a groove 31 in the form of a concave chute formed on the face upper of each support element 20.
thus two pre-longitudinal support members feeling some possibility of articulation of the upper element 20 with respect to the two elements supporting elements 30.
As already described for the elements superiors 2 and the basic elements l it is pos-likely to achieve at least one series III of elements support ~ inside which we vary a number of dimension-structural and structural, such as, for example, width of the seating surface, the height of the element, the shape of the support members 31, the na-structure of the concrete used and the constitution of the iron _, mocking, etc ....
By way of example, in FIG. 13, two series III, III ′ have been represented diagrammatically supporting elements each corresponding to a width L'l and L'2 of the seat surface and in which we varied the shapes of the elements ment.
In addition to the series, 1, 1 '.... of elements of base 1 and 11, It '.... of upper elements 2, iO we thus have at least one additional series shut up 111 basic elements and, if necessary, we can therefore combine the arch elements 20 chosen from the corresponding series, either at raft elements corresponding to the same width between supports, either to isolated support elements chosen from an additional series 111, 111 ' with a seating surface compatible with the soil lift.
Replacement of a lower element monobloc by two ~ separate support elements not significantly change the maximum load allowed-because it depends mainly on the arch resistance, the role of the raft being basically to transmit the load to the ground applied to the vault and ensure a seal down.
The space existing between the two elements separate support elements 30 may, as the case may be left free or closed in any suitable way corresponding to the use of the conduit.
In Figure 9, for example, the part lower 4 of the duct consists of a basic che 41 in compact aggregates ~ s, placed between the internal lateral sides of the elements 33 support 30 and covered with a slab 42 which can -be made up of prefabricated elements or casting in place by covering the upper faces res 34 of the supporting elements 30.
We can thus, as shown in Figure 10, pass between the two lines support genes 3 a roadway 43 and it can be seen that one of the advantages of this arrangement is in that pavement 43 can be realized continuously and conventionally inside laughing as on the outside of the duct while lower concrete elements would impose a connection cordage with the outer shoe with the risk of offset due to differential settlement tials and dilations.
Furthermore, the joint plans transverse 23 between two arch elements 20 can be shifted longitudinally relative to the plane of the transverse joints 35 in-tre the support elements 30. In this way, the char-ge applied by each upper element 20 spread over two consecutive support elements, on either side of the parting line.
The transverse joints between two elements 30 consecutive runs can be done in different many ways.
In Figure 11, for example, we have presented a sealed joint 5 between two elements consecutive 30, 30 '. These are equipped, on their front faces opposite, of reinforcements waiting 51 which intersect in a space 50 left between the two elements 30 and 30 'and which are associated with transverse irons 52, the whole being drowned in a mortar of seal-ment 53. The sealing joint 5 thus produced between the two consecutive elements 30 and 30 ' constitutes a real keyage in the long term tudinal. ~ n thus joining a number of consecutive elements, we realize, over a long determined hunger, a monobloc sill which allows distribute the load on the ground and avoid differential settlements.
But it is also possible, as we have shown in Figure 4, to place at the extremi-tees opposite two consecutive elements 30 and 30 ', linkage organs 54, 54' which fit into each other and can be re-linked by a pin 5 ~. The two elements cutives 30 and 30 'are thus interconnected by an articulated connection giving each element a i5 slight possibility of deviation from elements that frame it.
~ ien heard, the dimensions of ele-supporting elements 30 and in particular the width L 'of their seat surface and their height H 'will be chosen according to the circumstances of use, and in particular of the supported loads and the bearing capacity of the soil.
Different profiles may also be planned. For example, for the realization of underground roads, at least one of the lines support 3 could be made up of elements 30 shaped so as to have an upper face 34 'substantially horizontal and placed above from pavement level 4 so as to achieve a pedestrian traffic sidewalk.
Other prefabricated accessories for-could also be advantageously added to the series of support elements 30.
For example, the internal side of the elements 30 units may be fitted with parts Z0 ~ 312 ~

to form or receive circulation rails tion of a trolley or gantry facilitating the mounting age and / or maintenance of the structure.
According to another variant shown on Figures 14 and 15, the duct is provided for the passage of liquid, for example from a river.
In this case, the bottom 6 of the duct can be advantageously made up of a series of plates 61 made of cast iron, sheet metal or plastic, having a width equal to that of the duct and re-covering the space between the two elements 30, in going up on the upper faces 34 thereof, up to the joints 31. As shown on In the figure, the plates 61 can limit a pro-hollow wire, for example for the passage of a cable nal and the height H 'of the support elements 30 can be increased to raise the level of joints 31 to above the average level of water, the bottom 6 thus limiting a section sufficient for average flows. Seals sealing can be placed between the parts upper 31 of the supporting elements 30 and the upper edges 62 of each plate 6 so as to allow the water level to rise above of the level of the edges 62 by filling more or minus the conduit, in the event of a flood. The conduit can even be pressurized if the edges below laughers 21 of the vault 2 are applied in the bottom of grooves 31 by tie rods under tension if we.
In addition, as shown in the perspective view of Figure 6, the plates 61 can advantageously overlap each other ~ like a covering, the transverse end 63 from a plate facing downstream, in the -direction of liquid flow, covering The front end 64 of the following plate 69, with the interposition of a sealing bead.
Other modes of bottom coating could obviously be used. It is possible ble in some cases that the longi tudinal axis lO
of the duct be inclined relative to The horizontal and the support elements 30 can then have a tendency to sneak. To avoid it, he it will be interesting to plan on the undersides laughs 32 of the elements 30, hooking notches 37 which can be carried out in concreting or else, as shown in Figure 6, being mete swam on a cast iron plate 3 ~ sealed on the underside of each support element 30.
As shown in Figure 15, if steep gradient, the seat faces 16 of the elements basic elements l or 32 supporting elements 30 for should form steps, the laying surface A
constituting steps of corresponding widths.
To avoid any danger of slipping, the elements 30 can be anchored in the ground by transverse beams forming keys. It the same is true of upper elements 2 which can be keyed to the basic elements l.
According to another advantageous arrangement shown in Figures lO and 15, we have attached to the upper elements 2 of the head pieces 9 placed at each end of the pipe.
Indeed, the conduit is buried under a embankment C and ends at each end in a slope C 'which must be maintained by both sides lateral. To avoid unnecessary extension of the led outside the embankment C, we will use advantageously head pieces comprising each cune a vertical wall 9 of triangular shape or tr apézo i da le, as soc i ée with a s eme l I e 90.

, _ In Figures 2 and 6, for example, the sole 90 consists of one or more support elements 39 identical to those 30 which carry the arch elements 20. Each piece of t ~ te then consists of a plate 9 compre-ning a horizontal side 91 which rests on the upper tie 31 of the support element 39 corresponding, a vertical side 92 placed in the extension of side 24 of the last upper element 25 of the duct, and an inclined side 93 whose inclination corresponds to the natural angle of the ta-read C '.
Maintaining the wall 9 can be secured by a seal made ~ between the sides vertical 92 and 24 facing each other or by embo1-adequate parts sealed in the faces opposite said sides 91, 24.
In addition, the wall 9 is supported, in the longitudinal direction, on a stop 37 closing the chute 31 into which the horizontal side engages zontal 91.
But we could also make parts these head each provided with a sole 90 making body with the vertical wall 9, so as to be a freestanding element.
Therefore, we can still add to series III, III 'of upper and lower elements laughing, a series of head pieces presenting thicknesses, heights and, optionally, different inclinations so as to be able adapt to different cases of the best way.
Generally speaking, we can imagine other variants and others accessory provisions, for example for differently serve the bottom or the upper part of the duct.

Claims

THE ACHIEVEMENTS OF THE INVENTION ABOUT WHICH A RIGHT
EXCLUSIVE OF OWNERSHIP OR PRIVILEGE IS CLAIMED, ARE
DEFINED AS FOLLOWS:

1. Method for producing a buried conduit constituted of a series of contiguous sections placed one after the others, along a longitudinal axis (O), on the bottom of a trench, said sections being formed by assembly on the site of prefabricated elements and each comprising, in section transverse to the axis (O), a lower part made up of less a basic element and forming a raft resting on a laying surface and an upper part consisting of at least an element forming a vault and resting on the lower part by through longitudinal support members respectively, parallel to the longitudinal axis (O), on the lateral sides of the lower part and the superior; characterized by the fact that everything is determined first, the dimensional and structural characteristics at least one series (I) of basic elements and at least one series (II) of upper elements, each series corresponding to a certain width between the longitudinal supports (L1), making vary, in each series, at least one of the shape parameters and strength such as the cross-sectional profile, the thickness and the constitution of the element, which we associate then, in any way possible, elements superior and basic elements compatible with each other, so as to constitute standard sections having, for the width (L1) chosen, profiles, thicknesses and constitutions different, which we determine, for each typical section as well formed, the maximum admissible distributed load by the typical section considered under various conditions of use, and that, for the realization of a conduit having to present a section of passage (S) and a given size, and subject to a load given, we choose a typical section with a load permissible greater than the load to be applied to the duct and whose profile, taking into account the width between supports, allows optimal respect of the cross-section passage and space required and we manufacture in desired number basic and superior elements presenting the profile, the dimensions and structural characteristics of the element of the lower part and the upper part of the typical section chosen, then we build the conduit by assembling said elements.

2. Method for producing a conduit according to the claim 1, characterized in that one adds to the series (I, II) of basic and superior elements, at minus an additional series (III) of support elements forming each an insulated sole having, on a lower face, a seating surface and, on an upper face, a portion longitudinal support for an upper element and in which at least one of the defining characteristics was varied lift and resistance, such as the width (L ') of the seat surface, thickness (H '), shape and construction and that, to make at least part of the duct, we choose in a series III, III ', supporting elements which are placed one after the other so that the supporting parts aligned form the two longitudinal support members on which come to rest the lower lateral edges of the upper elements, said support elements being chosen from said additional series (III) so as to be able to withstand the loads applied in service by the elements and ensure a wide seat surface (L ') sufficient, taking into account the said loads and the bearing capacity of the soil (A) at this location.

3. Method according to one of claims 1 or 2 characterized in that, to check the maximum load admissible by each standard section, real size the upper elements and the basic elements chosen in said series (I, II, III) and corresponding respectively to different widths (L1, L2 ...), each element in a series being made, for each width, in a corresponding number the possibilities of combinations with the elements of another series and we associate in pairs the basic elements and upper elements so as to make the standard sections envisaged, then each standard section thus formed is subjected to a load test applied to the wrench until the section is ruined to deduce, by applying safety coefficients, the maximum permissible distributed load by the section considered.

4. Method according to claim 1, characterized by the fact that we realize a number of series I of elements to write off and a number of series II of superior elements corresponding to the same number of widths (L1, L2 ...) said number being determined to cover almost continuously, thanks to the choice of profile, a wide range of passage sections and combines superior elements and elements to strike out in the same way width between supports (L) to form standard sections corresponding to this width (L).

5. Method according to claim 3, characterized by the fact that we realize a number of series I of elements to write off and a number of series II of superior elements corresponding to the same number of widths (L1, L2 ...) said number being determined to cover almost continuously, thanks to the choice of profile, a wide range of passage sections and combines superior elements and elements to strike out in the same way width between supports (L) to form standard sections corresponding to this width (L).

6. Method according to one of claims 1, 2, 4, or 5, characterized by the fact that one spans along both sides side of each basic element, of the sides, perpendicular to the bottom, the height of which is varied the interior of the series (I) so as to have several levels (h1) of the longitudinal support part.

7. Method according to claim 3, characterized by the fact that one spares along the two lateral sides of each basic element, pedestals, perpendicular to the bottom of which varies the height inside the series (I) so that have several levels (h1) of the support part longitudinal.

8. Method according to one of claims 1, 2, 4, 5 or 7, characterized in that, in each series II of elements upper ones corresponding to a width between supports (L) determined, we vary the curvature of the element and particular the ratio between the arrow and the width between supports.

9. Method according to claim 3, characterized by the fact that in each series II of superior elements corresponding to a determined width between supports (L), we do vary the curvature of the element and in particular the ratio between the arrow and the width between supports.

10. Method according to claim 6, characterized by the fact that in each series II of superior elements corresponding to a determined width between supports (L), we do vary the curvature of the element and in particular the ratio between the arrow and the width between supports.

11. Method according to one of claims 1, 2, 4, 5, 7, 9 or 10, characterized by the fact that all of the characteristics of standard sections in a catalog indicating in particular the widths between supports (L1, L2 ...) and the widths and seat of the different series (I, I ') (III, III') of elements base and (II, II ') of upper elements produced and, for each width between supports (L1, L2 ...) the section profiles types with indication of cross section and load maximum allowable.

12. Method according to claim 3, characterized by the fact that we group together all the characteristics of standard sections in a catalog indicating in particular the widths between supports (L1, L2 ...) and the widths and seat of different series (I, I ') (III, III') of basic elements and (II, II ') of upper elements produced and, for each width between press (L1, L2 ...) the profiles of the standard sections with the indication of the passage section and the maximum load eligible.

13. Method according to claim 6, characterized by the fact that we group together all the characteristics of standard sections in a catalog indicating in particular the widths between supports (L1, L2 ...) and the widths and seat of different series (I, I ') (III, III') of basic elements and (II, II ') of upper elements produced and, for each width between press (L1, L2 ...) the profiles of the standard sections with the indication of the passage section and the maximum load eligible.

14. Method according to claim 8, characterized by the fact that we group together all the characteristics of standard sections in a catalog indicating in particular the widths between supports (L1, L2 ...) and the widths and seat of different series (I, I ') (III, III') of basic elements and (II, II ') of upper elements produced and, for each width between press (L1, L2 ...) the profiles of the standard sections with the indication of the passage section and the maximum load eligible.

15. Method for producing a conduit according to the claim 2, characterized in that between the two lines of supporting elements a series of elements intermediaries based on the internal parts of the elements of support of the two lines so as to form the bottom of the conduit.

16. Method for producing a conduit according to the claim 2, characterized in that, in the event that the conduit is used for the passage of a roadway circulation, the latter is carried out without discontinuity in passing between the two lines of support elements.

17. Prefabricated elements for implementing the process according to one of claims 1, 2, 4, 5, 7, 9, 10, 12, 13, 14, or 16 of a buried conduit formed of contiguous sections each comprising, in cross section, a lower part consisting of at least one basic element resting on a surface (A) and an upper part consisting of at least one arch element and resting on the lower part by through longitudinal support members respectively parallel to the longitudinal axis (O) of the duct, on the lateral sides of the lower part and of the part superior, characterized by the fact that they are divided into several series, respectively at least one series I of elements basic comprising at least two basic elements and a series (II) upper elements comprising at least two elements upper ones covering the same width between supports (L1) and differing from each other by at least one of the characteristics determining shape and strength, such as the profile cross section, thickness and constitution of the item.

18. Prefabricated elements for implementing the process according to claim 3 of a buried conduit formed of sections contiguous each comprising, in cross section, a portion lower consisting of at least one basic element resting on a laying surface (A) and an upper part consisting of less an element forming a vault and resting on the part lower via longitudinal support members formed respectively parallel to the longitudinal axis (O) of the duct, on the lateral sides of the lower part and the upper part, characterized by the fact that they are distributed in several series, respectively at least one series I
basic elements comprising at least two basic elements and a series (II) of upper elements comprising at least two upper elements covering the same width between supports (L1) and differing from each other by at least one of the characteristics determining shape and strength, such as the profile cross section, thickness and constitution of the item.

l9. Prefabricated elements for implementing the process according to claim 6 of a buried conduit formed of sections contiguous each comprising, in cross section, a portion lower consisting of at least one basic element resting on a laying surface (A) and an upper part consisting of less an element forming a vault and resting on the part lower via longitudinal support members formed respectively parallel to the longitudinal axis (O) of the duct, on the lateral sides of the lower part and the upper part, characterized by the fact that they are distributed in several series, respectively at least one series I
basic elements comprising at least two basic elements and a series (II) of upper elements comprising at least two upper elements covering the same width between supports (L1) and differing from each other by at least one of the characteristics determining shape and strength, such as the profile cross section, thickness and constitution of the item.

20. Prefabricated elements for implementing the process according to claim 8 of a buried conduit formed of sections contiguous each comprising, in cross section, a portion lower consisting of at least one basic element resting on a laying surface (A) and an upper part consisting of less an element forming a vault and resting on the part lower via longitudinal support members formed respectively parallel to the longitudinal axis (O) of the duct, on the lateral sides of the lower part and the upper part, characterized by the fact that they are distributed in several series, respectively at least one series I
basic elements comprising at least two basic elements and a series (II) of upper elements comprising at least two upper elements covering the same width between supports (L1) and differing from each other by at least one of the characteristics determining shape and strength, such as the profile cross section, thickness and constitution of the item.

21. Prefabricated elements for implementing the process according to claim 11 of a buried conduit formed of sections contiguous each comprising, in cross section, a portion lower consisting of at least one basic element resting on a laying surface (A) and an upper part consisting of less an element forming a vault and resting on the part lower via longitudinal support members formed respectively parallel to the longitudinal axis (O) of the duct, on the lateral sides of the lower part and the upper part, characterized by the fact that they are distributed in several series, respectively at least one series I
basic elements comprising at least two basic elements and a series (II) of upper elements comprising at least two upper elements covering the same width between supports (L1) and differing from each other by at least one of the characteristics determining shape and strength, such as the profile cross section, thickness and constitution of the item.

22. Prefabricated elements according to claim 17, characterized by the fact that we add to the series (I, I ') basic elements, at least one additional set of elements support each forming an insulated sole and likely to be associated with the upper elements, the elements of said series additional (III) differing from each other by at least one characteristics determining the lift, the size and the resistance, such as the width (L ') of the seating surface, the height (H ') of the supports, the shape and the constitution.

23. Prefabricated elements according to one of claims 18, 19, 20 or 21, characterized by the fact that the series (I, I ') of basic elements, at least one series additional support elements each forming a sole isolated and likely to be associated with the superior elements, the elements of said additional series (III) differing one on the other by at least one of the defining characteristics lift, size and strength, such as width (L ') of the seating surface, height (H') of the supports, form and constitution.

24. Prefabricated elements according to claim 17, characterized in that each series (I, I ') of elements of base corresponding to a determined width between supports (L) includes at least elements consisting of a panel rectangular forming a bottom provided along its lateral sides of raised parts forming pedestals each provided, at its upper part, a support part of the upper element whose level in relation to the bottom can vary from one element to the other inside each series (I) (I ').

25. Prefabricated elements according to one of claims 18, 19, 20 or 21, characterized in that each series (I, I ') of basic elements corresponding to a width between supports determined (L) includes at least elements made up of a rectangular panel forming a bottom provided along its sides sides of raised parts forming fitted sidewalls each, at its upper part, of a support part of the element higher whose level compared to the bottom may vary by element to another within each series (I) (I ').

26. Prefabricated elements according to claim 17, characterized by the fact that some of the basic elements of series (I) (I ') and supporting elements of series (III, III') are provided on their underside with projecting parts of anchoring the element on the laying surface (A).

27. Prefabricated elements according to one of claims 18, 19, 20, 21, 22 or 24, characterized by the fact that some basic elements of the series (I) (I ') and supporting elements series (III, III ') are provided on their underside with protruding parts for anchoring the element on the laying surface (AT).

28. Prefabricated elements according to claim 23, characterized by the fact that some of the basic elements of series (I) (I ') and supporting elements of series (III, III') are provided on their underside with projecting parts of anchoring the element on the laying surface (A).

29. Prefabricated elements according to claim 25, characterized by the fact that some of the basic elements of series (I) (I ') and supporting elements of series (III, III') are provided on their underside with projecting parts of anchoring the element on the laying surface (A).

30. Prefabricated elements according to claim 17, characterized by the fact that the seating surface of the base forms stepped steps which can be placed on steps A2 provided on the laying surface A in the event of an inclination of the longitudinal axis (O) of the duct.

31. Prefabricated elements according to one of claims 18, 19, 20, 21, 22 or 24, characterized in that the surface of basic elements form tiered guards likely to be placed on A2 steps on the laying surface A in case of inclination of the longitudinal axis (O) of the conduit.

32. Prefabricated elements according to claim 23, characterized by the fact that the seating surface of the base forms stepped guards likely to be placed on steps A2 provided on the laying surface A in a box of inclination of the longitudinal axis (O) of the duct.

33. Prefabricated elements according to claim 25, characterized by the fact that the seating surface of the base forms stepped guards likely to be placed on steps A2 provided on the laying surface A in a box of inclination of the longitudinal axis (O) of the duct.

34. Prefabricated elements according to claim 17, characterized by the fact that each series (I, I ') of elements of base corresponding to a width between supports (L) determined includes at least one element, the bottom of which is fitted with a sieve axial.

35. Prefabricated elements according to one of claims 18, 19, 20, 21, 22, 24, 26, 28, 29, 30, 32 or 33, characterized by the fact that each series (I, I ') of basic elements corresponding to a determined width between supports (L) includes at least one element, the bottom of which is provided with an axial wedge.

36. Prefabricated elements according to claim 23, characterized by the fact that each series (I, I ') of elements of base corresponding to a width between supports (L) determined includes at least one element, the bottom of which is fitted with a sieve axial.

37. Prefabricated elements according to claim 25, characterized by the fact that each series (I, I ') of elements of base corresponding to a width between supports (L) determined includes at least one element, the bottom of which is fitted with a sieve axial.

38. Prefabricated elements according to claim 27, characterized by the fact that each series (I, I ') of elements of base corresponding to a width between supports (L) determined includes at least one element, the bottom of which is fitted with a sieve axial.

39. Prefabricated elements according to claim 31, characterized by the fact that each series (I, I ') of elements of base corresponding to a width between supports (L) determined includes at least one element, the bottom of which is fitted with a sieve axial.

40. Prefabricated elements according to one of claims 34, 36, 37, 38 or 39, characterized in that the face bottom of the bottom has a central part projecting from relative to the lower level of the lateral sides of the element base and engaging in a corresponding recess (A1) in the laying surface.

41. Prefabricated elements according to claim 35, characterized by the fact that the underside of the bottom has a central part projecting from the lower level lateral sides of the base element and engaging in a corresponding recess (A1) formed in the laying surface.

42. Prefabricated elements according to claim 17, characterized by the fact that each series (I, I ') of elements of base corresponding to a width between supports (L) determined includes basic elements provided along their edges transverse to the axis of the structure, of centering parts, projecting and recessed respectively, the projecting parts and in hollow of two consecutive basic elements fitting one in the other to the installation of said elements.

43. Prefabricated elements according to one of claims 18, 19, 20, 21, 22, 24, 26, 28, 29, 30, 32, 33, 34, 36, 37, 38 or 39, characterized in that each series (I, I ') basic elements corresponding to a width between supports (L) determined includes basic elements provided along their edges transverse to the axis of the structure, of parts of centering, respectively projecting and recessed, the parts in protrusion and recess of two consecutive basic elements fitting into each other when fitting said elements.

44. Prefabricated elements according to claim 23, characterized by the fact that each series (I, I ') of elements of base corresponding to a width between supports (L) determined includes basic elements provided along their edges transverse to the axis of the structure, of centering parts, projecting and recessed respectively, the projecting parts and in hollow of two consecutive basic elements fitting one in the other to the installation of said elements.

45. Prefabricated elements according to claim 25, characterized by the fact that each series (I, I ') of elements of base corresponding to a width between supports (L) determined includes basic elements provided along their edges transverse to the axis of the structure, of centering parts, projecting and recessed respectively, the projecting parts and in hollow of two consecutive basic elements fitting one in the other to the installation of said elements.

46. Prefabricated elements according to claim 27, characterized by the fact that each series (I, I ') of elements of base corresponding to a width between supports (L) determined includes basic elements provided along their edges transverse to the axis of the structure, of centering parts, projecting and recessed respectively, the projecting parts and in hollow of two consecutive basic elements fitting one in the other to the installation of said elements.

47. Prefabricated elements according to claim 31, characterized by the fact that each series (I, I ') of elements of base corresponding to a width between supports (L) determined includes basic elements provided along their edges transverse to the axis of the structure, of centering parts, projecting and recessed respectively, the projecting parts and in hollow of two consecutive basic elements fitting one in the other to the installation of said elements.

48. Prefabricated elements according to claim 35, characterized by the fact that each series (I, I ') of elements of base corresponding to a width between supports (L) determined includes basic elements provided along their edges transverse to the axis of the structure, of centering parts, projecting and recessed respectively, the projecting parts and in hollow of two consecutive basic elements fitting one in the other to the installation of said elements.

49. Prefabricated elements according to claim 17, characterized by the fact that at least some of the elements of base are provided with at least one tubular recess formed in the thickness of the bottom and parallel to the axis (0) so that the aligned tubular recesses of several basic elements consecutive form an internal channel extending over the entire length of the structure.

50. Prefabricated elements according to one of claims 18, 19, 20, 21, 22, 24, 26, 28, 29, 30, 32, 33, 34, 36 to 39, 41, 42 or 44 to 48, characterized in that at least some of the basic elements are provided with at least one tubular recess formed in the thickness of the bottom and parallel to the axis (0) of such so that the aligned tubular recesses of several elements of consecutive bases form an internal channel extending over all the length of the structure.

51. Prefabricated elements according to claim 23, characterized by the fact that at least some of the elements of base are provided with at least one tubular recess formed in the thickness of the bottom and parallel to the axis (0) so that the aligned tubular recesses of several basic elements consecutive form an internal channel extending over the entire length of the structure.

52. Prefabricated elements according to claim 25, characterized by the fact that at least some of the elements of base are provided with at least one tubular recess formed in the thickness of the bottom and parallel to the axis (0) so that the aligned tubular recesses of several basic elements consecutive form an internal channel extending over the entire length of the structure.

53. Prefabricated elements according to claim 27, characterized by the fact that at least some of the elements of base are provided with at least one tubular recess formed in the thickness of the bottom and parallel to the axis (0) so that the aligned tubular recesses of several basic elements consecutive form an internal channel extending over the entire length of the structure.

54. Prefabricated elements according to claim 31, characterized by the fact that at least some of the elements of base are provided with at least one tubular recess formed in the thickness of the bottom and parallel to the axis (0) so that the aligned tubular recesses of several basic elements consecutive form an internal channel extending over the entire length of the structure.

55. Prefabricated elements according to claim 35, characterized by the fact that at least some of the elements of base are provided with at least one tubular recess formed in the thickness of the bottom and parallel to the axis (0) so that the aligned tubular recesses of several basic elements consecutive form an internal channel extending over the entire length of the structure.

56. Prefabricated elements according to claim 40, characterized by the fact that at least some of the elements of base are provided with at least one tubular recess formed in the thickness of the bottom and parallel to the axis (0) so that the aligned tubular recesses of several basic elements consecutive form an internal channel extending over the entire length of the structure.

57. Prefabricated elements according to claim 43, characterized by the fact that at least some of the elements of base are provided with at least one tubular recess formed in the thickness of the bottom and parallel to the axis (0) so that the aligned tubular recesses of several basic elements consecutive form an internal channel extending over the entire length of the structure.

58. Prefabricated elements according to claim 17, characterized by the fact that each series (II) of elements upper ones corresponding to a determined width between supports includes elements with at least two different profiles chosen from different types of profiles, respectively one low profile with curved basket handle, one profile circular, raised ovoid profile, box profile rectangular and a flat slab profile.

59. Prefabricated elements according to one of claims 18, 19, 20, 21, 22, 24, 26, 28, 29, 30, 32, 33, 34, 36 to 39 or 41, characterized in that each series (II) of elements upper ones corresponding to a determined width between supports includes elements with at least two different profiles chosen from different types of profiles, respectively one low profile with curved basket handle, one profile circular, raised ovoid profile, box profile rectangular and a flat slab profile.

60. Prefabricated elements according to claim 23, characterized by the fact that each series (II) of elements upper ones corresponding to a determined width between supports includes elements with at least two different profiles chosen from different types of profiles, respectively one low profile with curved basket handle, one profile circular, raised ovoid profile, box profile rectangular and a flat slab profile.

61. Prefabricated elements according to claim 25, characterized by the fact that each series (II) of elements upper ones corresponding to a determined width between supports includes elements with at least two different profiles chosen from different types of profiles, respectively one low profile with curved basket handle, one profile circular, raised ovoid profile, box profile rectangular and a flat slab profile.

62. Prefabricated elements according to claim 27, characterized by the fact that each series (II) of elements upper ones corresponding to a determined width between supports includes elements with at least two different profiles chosen from different types of profiles, respectively one low profile with curved basket handle, one profile circular, raised ovoid profile, box profile rectangular and a flat slab profile.

63. Prefabricated elements according to claim 31, characterized by the fact that each series (II) of elements upper ones corresponding to a determined width between supports includes elements with at least two different profiles chosen from different types of profiles, respectively one low profile with curved basket handle, one profile circular, raised ovoid profile, box profile rectangular and a flat slab profile.

64. Prefabricated elements according to claim 35, characterized by the fact that each series (II) of elements upper ones corresponding to a determined width between supports includes elements with at least two different profiles chosen from different types of profiles, respectively one low profile with curved basket handle, one profile circular, raised ovoid profile, box profile rectangular and a flat slab profile.

65. Prefabricated elements according to claim 40, characterized by the fact that each series (II) of elements upper ones corresponding to a determined width between supports includes elements with at least two different profiles chosen from different types of profiles, respectively one low profile with curved basket handle, one profile circular, raised ovoid profile, box profile rectangular and a flat slab profile.

66. Prefabricated elements according to claim 17, characterized by the fact that each longitudinal support member articulated comprises two profiled parts, respectively convex and concave formed respectively projecting and recessed along lateral sides facing the upper element and the basic element of each section.

67. Prefabricated elements according to one of claims 18 to 22, 24, 26, 28 to 30, 32 to 34, 36 to 39, 41, 42, 44 to 49, 51 to 58 or 60 to 65, characterized in that each organ articulated longitudinal support comprises two profiled parts, respectively convex and concave formed respectively in protruding and recessed along the lateral sides opposite the upper element and the basic element of each section.

68. Prefabricated elements according to claim 23, characterized by the fact that each longitudinal support member articulated comprises two profiled parts, respectively convex and concave formed respectively projecting and recessed along lateral sides facing the upper element and the basic element of each section.

69. Prefabricated elements according to claim 25, characterized by the fact that each longitudinal support member articulated comprises two profiled parts, respectively convex and concave formed respectively projecting and recessed along lateral sides facing the upper element and the basic element of each section.

70. Prefabricated elements according to claim 27, characterized by the fact that each longitudinal support member articulated comprises two profiled parts, respectively convex and concave formed respectively projecting and recessed along lateral sides facing the upper element and the basic element of each section.

71. Prefabricated elements according to claim 31, characterized by the fact that each longitudinal support member articulated comprises two profiled parts, respectively convex and concave formed respectively projecting and recessed along lateral sides facing the upper element and the basic element of each section.

72. Prefabricated elements according to claim 35, characterized by the fact that each longitudinal support member articulated comprises two profiled parts, respectively convex and concave formed respectively projecting and recessed along lateral sides facing the upper element and the basic element of each section.

73. Prefabricated elements according to claim 40, characterized by the fact that each longitudinal support member articulated comprises two profiled parts, respectively convex and concave formed respectively projecting and recessed along lateral sides facing the upper element and the basic element of each section.

74. Prefabricated elements according to claim 43, characterized by the fact that each longitudinal support member articulated comprises two profiled parts, respectively convex and concave formed respectively projecting and recessed along lateral sides facing the upper element and the basic element of each section.

75. Prefabricated elements according to claim 50, characterized by the fact that each longitudinal support member articulated comprises two profiled parts, respectively convex and concave formed respectively projecting and recessed along lateral sides facing the upper element and the basic element of each section.

76. Prefabricated elements according to claim 59, characterized by the fact that each longitudinal support member articulated comprises two profiled parts, respectively convex and concave formed respectively projecting and recessed along lateral sides facing the upper element and the basic element of each section.

77. Prefabricated elements according to one of claims 66 or 68 to 76, characterized in that the parts profiles, respectively convex and concave extend alternately on two different levels so as to achieve along each base element and each upper element, inverted niche profiles comprising, on the element of base of the recessed and projecting parts in which reverse parts arranged respectively in protruding and recessed on the lateral sides of the element superior.

78. Prefabricated elements according to claim 67, characterized by the fact that the profiled parts, respectively convex and concave extend alternately over two different levels so as to carry along each basic element and each upper element, profiles in inverted slots comprising, on the basic element of the parts recessed and protruding in which engage parties inverses arranged respectively in projecting and recessed on the lateral sides of the upper element.

79. Prefabricated elements for the realization of a duct according to one of claims 1, 2, 4, 5, 7, 9, 10 or 12 to 16, characterized by the fact that they comprise at least one series intermediate elements that can be placed following the others so as to form the bottom of the conduit, said elements being made of moldable, injectable or laminated, such as metal, concrete or plastics.

80. Prefabricated elements for the realization of a duct according to claim 3, characterized in that they include at least a series of intermediate elements likely to be placed one after the other so to form the bottom of the duct, said elements being made of moldable, injectable or laminated material, such as metal, concrete or plastics.

81. Prefabricated elements for the realization of a duct according to claim 6, characterized in that they include at least a series of intermediate elements likely to be placed one after the other so to form the bottom of the duct, said elements being made of moldable, injectable or laminated material, such as metal, concrete or plastics.

82. Prefabricated elements for the realization of a duct according to claim 8, characterized in that they include at least a series of intermediate elements likely to be placed one after the other so to form the bottom of the duct, said elements being made of moldable, injectable or laminated material, such as metal, concrete or plastics.

83. Prefabricated elements for the realization of a duct according to claim 11, characterized in that they include at least a series of intermediate elements likely to be placed one after the other so to form the bottom of the duct, said elements being made of moldable, injectable or laminated material, such as metal, concrete or plastics.

84. Prefabricated elements according to claim 79, characterized by the fact that the bottom of the duct forms a channel for the circulation of a liquid and that the elements intermediates consist of plates substantially covering the entire internal width of the conduit and overlapping each other like a covering, the downstream end of a plate covering the upstream end of the next plate.

85. Prefabricated elements according to one of claims 80 to 83, characterized in that the bottom of the duct forms a channel for the circulation of a liquid and that the elements intermediates consist of plates substantially covering the entire internal width of the conduit and overlapping each other like a covering, the downstream end of a plate covering the upstream end of the next plate.

86. Prefabricated elements for the realization of a duct according to claim 2, characterized in that at least some of the support elements have waiting reinforcements likely to be associated with transverse reinforcement and submerged after installation in a sealing binder so as to form a keyed joint, the set of several elements consecutive thus constituting a monobloc sill.

87. Prefabricated elements for the realization of a duct according to claim 2, characterized in that the adjacent ends of the supporting elements of the same line are provided with connecting members interconnected so as to form a link articulated around an axis.

88. Buried duct produced according to one of claims 1, 2, 4, 5, 7, 9, 10 or 12 to 16, by assembly on site prefabricated elements chosen from at least two series (I, II), respectively, of lower elements and of elements superiors, in which at least one of the characteristics determining the shape and the resistance, characterized in that, the duct being covered with a embankment (C) bounded by an embankment (C '), each end of the conduit opening into the slope (C ') is equipped with two head pieces placed respectively in the extension of the two sides of the duct, and each comprising a side wall element of bias shape resting on a support sole and susceptible to be placed respectively in the extension of the two sides lateral of the upper element placed at the end of the duct, each side wall element having a shape substantially trapezoidal or triangular with one horizontal side resting on the support base, a corresponding side of the upper element and an inclined side whose inclination corresponds to the natural slope angle (C ') of the backfill covering leads him.

89. Buried conduit produced, according to claim 3, by assembly on the site of prefabricated elements chosen in au minus two sets (I, II), respectively, of lower elements and higher elements, in which we have varied minus one of the characteristics determining the shape and resistance, characterized in that, the conduit being covered with an embankment (C) limited by an embankment (C '), each end of the conduit opening into the slope (C ') is fitted of two head pieces placed respectively in the extension on both sides of the conduit, and each comprising a skew-shaped side wall element resting on a support sole and capable of being placed respectively in the extension of the two lateral sides of the upper element placed at the end of the duct, each side wall element having a substantially trapezoidal or triangular shape comprising a horizontal side resting on the support sole, a corresponding side of the upper element and an inclined side whose inclination corresponds to the natural slope angle (C ') of the embankment covering the duct.

90. Buried conduit produced, according to claims 6, by assembly on the site of prefabricated elements chosen in au minus two sets (I, II), respectively, of lower elements and higher elements, in which we have varied minus one of the characteristics determining the shape and resistance, characterized in that, the conduit being covered with an embankment (C) limited by an embankment (C '), each end of the conduit opening into the slope (C ') is fitted of two head pieces placed respectively in the extension on both sides of the conduit, and each comprising a skew-shaped side wall element resting on a support sole and capable of being placed respectively in the extension of the two lateral sides of the upper element placed at the end of the duct, each side wall element having a substantially trapezoidal or triangular shape comprising a horizontal side resting on the support sole, a corresponding side of the upper element and an inclined side whose inclination corresponds to the natural slope angle (C ') of the embankment covering the duct.

91. buried conduit produced, according to claim 8, by assembly on the site of prefabricated elements chosen in au minus two sets (I, II), respectively, of lower elements and higher elements, in which we have varied minus one of the characteristics determining the shape and resistance, characterized in that, the conduit being covered with an embankment (C) limited by an embankment (C '), each end of the conduit opening into the slope (C ') is fitted of two head pieces placed respectively in the extension on both sides of the conduit, and each comprising a skew-shaped side wall element resting on a support sole and capable of being placed respectively in the extension of the two lateral sides of the upper element placed at the end of the duct, each side wall element having a substantially trapezoidal or triangular shape comprising a horizontal side resting on the support sole, a corresponding side of the upper element and an inclined side whose inclination corresponds to the natural slope angle (C ') of the embankment covering the duct.

92. Buried duct produced, according to claim 11, by assembly on the site of prefabricated elements chosen in au minus two sets (I, II), respectively, of lower elements and higher elements, in which we have varied minus one of the characteristics determining the shape and resistance, characterized in that, the conduit being covered with an embankment (C) limited by an embankment (C '), each end of the conduit opening into the slope (C ') is fitted of two head pieces placed respectively in the extension on both sides of the conduit, and each comprising a skew-shaped side wall element resting on a support sole and capable of being placed respectively in the extension of the two lateral sides of the upper element placed at the end of the duct, each side wall element having a substantially trapezoidal or triangular shape comprising a horizontal side resting on the support sole, a corresponding side of the upper element and an inclined side whose inclination corresponds to the natural slope angle (C ') of the embankment covering the duct.

93. Buried pipe according to claim 88, characterized by the fact that we have a series of head pieces in which we varied at least one of the parameters such as the thickness of the wall, the height of the vertical side, the inclination of the inclined side and the width of the sole support.

94. Buried pipe according to one of claims 89 to 92, characterized in that there is a series of head pieces in which at least one of the parameters such as wall thickness, side height vertical, the inclination of the inclined side and the width of the support sole.