EP3682062A1

EP3682062A1 - Retaining wall comprising precast piles and pile for such a wall

Info

Publication number: EP3682062A1
Application number: EP18779786.5A
Authority: EP
Inventors: Blaise Fleury; Frédéric MAYORAZ; Erdjan OPAN; Agnès Petit; Adrian FORRER
Original assignee: Creabeton Materiaux SA
Current assignee: Creabeton Materiaux SA
Priority date: 2017-09-13
Filing date: 2018-09-12
Publication date: 2020-07-22
Also published as: CH714141A1; WO2019053615A1

Abstract

The invention relates to a concrete precast unitary draining pile (2) and a draining retaining wall (1) comprising a plurality of these piles. The pile, of at least 4 metres in length and of a maximum diameter between 40 and 150 cm, is provided with a longitudinal opening (26) intended for draining water vertically through the pile. The retaining wall comprises a plurality of these piles, each pile comprising a first portion driven into a hole (50) in the ground (5) and a second portion extending vertically above the ground. The wall may comprise panels (3) between the piles intended for holding back the ground (6). The method of assembling a retaining wall comprises a step of drilling at least two boreholes, inserting a pile in each hole and casting or spraying concrete between said piles.

Description

Retaining wall comprising prefabricated piles, and pile for such a wall

Technical area

The present invention relates to a retaining wall comprising prefabricated concrete piles.

STATE OF THE ART [0002] Realizations of roads, railways, buildings or any other type of structure generally require a remodeling of the surface of the natural terrain, often involving the creation of embankments.

The maximum slope slope depends on the mechanical properties of the soil and leads to horizontal footprints horizontal worth

approximately 1.5 times the height of the slope.

These significant rights of way are often incompatible with cadastral boundaries or existing or projected adjacent works.

It is technically possible to limit these footprints through the realization of the walls of artificial retaining walls. Depending on the conditions specific to each project, these can be for example:

- weight walls made of concrete or natural stone

- L-shaped retaining walls consisting of a sole and a reinforced concrete siding

- buttressed concrete or natural stone walls

- Berlin walls

- nailed or anchored walls

- molded walls

- drilled piles - armed earth

- Prefabricated concrete elements consisting of a siding and an anchor-shaped rear restraint system.

- a stack of modular prefabricated elements - etc.

Most of these types of support can be stabilized by anchors sealed in the ground.

Each type of support has its advantages, but also its disadvantages, which may be for example the need for rights of way or temporary or permanent support, an impossibility of the control of the execution, insufficient durability, significant consumption of materials that are incompatible with the principles of

sustainable development, an impossibility of achieving effective drainage, insufficient rigidity and therefore the risk of settlement of adjacent structures, too long realization time.

Thus, in the case of walls weight unreinforced concrete or natural stones, the stability is provided exclusively by the weight of the wall. Heavy walls are a robust and durable system, but have the disadvantage of requiring rights of way or temporary supports during their realization. This type of support also requires a large amount of materials, which is incompatible with the criterion of saving natural resources for sustainable development.

L-shaped retaining walls, consisting of a sole and a reinforced concrete facing, provide stability due to the weight of the ground above the sole. This type of wall must imperatively be armed to withstand the stresses generated by the terrain. Like heavy walls, this type of retaining has the disadvantage of requiring rights of way or temporary supports during their realization. In addition, recent studies and accidents have highlighted a risk of corrosion damage to the main reinforcement at the site of the return of concreting between the sole and the facing. This type of damage is particularly pernicious because it causes a sudden and abrupt rupture of the siding, without any observable preliminary signs. Another example of self-supporting retaining wall precast concrete is described in US7001 1 10 patent. Such a wall has an apparent face and a face against which the ground that the wall aims to retain. In this patent, the retaining wall is linked to the portal of a tunnel. This type of prefabricated retaining wall significantly reduces the time of implementation compared to walls cast on site. The design, sizing and application of this wall however remains limited to a tunnel wing wall or bridge.

The "Berlin walls" are formed of an alignment of metal profiles stuck vertically in the ground and whose gap between two consecutive profiles is filled by elements of wood, prefabricated concrete or shotcrete to as the excavation progresses. This type of support has the advantage of a very short completion time and does not require temporary rights of way.

However, due to the corrosion of the metal profiles, their durability is not ensured. They are therefore used for temporary supports, for example to hold the edges of a search during the duration of a construction site.

The walls of Paris are similar to the Berlin walls, but use reinforced concrete piles cast in place instead of metal profiles.

A major problem of Berlin and Paris walls is the accumulation of water that can form behind the siding. In order to avoid the stresses due to the hydrostatic thrust, this water is most often evacuated by means of holes, called barbacans, through the wall. This water flow causes unsightly marks and a proliferation of vegetation and moss on the visible side of the wall. In addition, this permanent humidity can lead to damage to the concrete siding in case of frost.

GB2232701 describes a retaining wall comprising two rows of pillars with a diameter between 75mm and 300mm sealed with spray cement. The front can be reinforced by a steel frame. This document provides no solution to the problem of water accumulation behind the wall.

FR2732383A1 relates to a draining formwork panel of plastic material or metal, for the formwork of a wall of

concrete retaining. This document only provides a solution to the problem of formwork drainage, but does not solve the problem of drainage through the retaining wall itself.

Brief summary of the invention

An object of the present invention is to provide a retaining wall free, or at least partially lacking, limitations of known retaining walls.

A particular object of the invention is to provide a retaining wall and a pile with great adaptability to the situation, great durability and rapid implementation. According to the invention, these objects are achieved in particular by means of a retaining wall of claim 1, a pile according to claim 20 and a method according to claim 24.

This solution has the advantage over the prior art to allow implementation in a single step of the structural member carrier and the drainage system. The implementation is fast, requires no excavation and no temporary support. Earth movements are thus reduced to the strict minimum.

In particular, the monolithic prefabricated concrete pile provides better durability because it lacks weak points created by resumption of concreting.

The type of concrete may vary depending on its position in the pile section.

The longitudinal opening through each pile is a drainage collector which fulfills its role independently. In the event of an accidental malfunction of the pile drainage system, drainage of the wall may be ensured by the adjacent piles.

Compared to conventional drainage systems with horizontal collector, the proposed solution therefore has a very favorable redundancy.

The flow of water through the longitudinal opening of the piles avoids an appearance of unsightly marks and a

proliferation of vegetation on the front faces of the walls and piles, due to an overflow of water accumulated at the rear of the wall. The implementation does not require a concrete footing under the panels.

This solution lends itself to sustainable use along high-speed roads or high-traffic railways, where a service life exceeding 50 years is required. Depending on the case, the prefabricated piles can be connected at the head by a cast-iron reinforced concrete sill, with or without tie rods.

The pile of the invention is multifunctional; it serves both as a structural element to retain the upstream land and the interlayers; it serves as a collector for drained water; and it allows, as an option, to pump the collected water.

Brief description of the figures

Examples of implementation of the invention are indicated in the description illustrated by the appended figures in which:

Figure 1 illustrates a horizontal section of a retaining wall according to the invention, in the case of secant piles;

FIG. 2 illustrates a horizontal section of a retaining wall according to the invention, for the case of piles regularly spaced and bridged by intermediate panels;

Figures 3 and 4 respectively illustrate a vertical section and elevation of a retaining wall according to the invention, in the case of regularly spaced piles, without sill at the head of the pile;

Figures 5 and 6 respectively illustrate a vertical section and an elevation of a retaining wall according to the invention, in the case of regularly spaced piles, with a sill at the head of the pile;

Figures 7 to 9 respectively illustrate a vertical section and horizontal sections in the projecting upper part and the lower part stuck of a retaining wall according to the invention, for the case of regularly spaced piles. Example (s) of embodiment of the invention

Figures 1 and 2 illustrate a retaining wall 1

comprising a plurality of piles 2 so as to retain a portion of land 5 located between the downstream levels 501 and upstream 502. In the case of Figure 1, the piles 2 are intersecting. In the case of Figure 2, the piles 2 are evenly spaced and serve as support for intermediate panels 3 which hold the ground in the final stage.

The spacing 206 of the piles is determined case by case depending on the geometry and properties of the ground 5, as well as possible vertical stresses of the ground located upstream of the wall of

Retaining. Preferably, the spacing 206 of the piles is less than 3 meters so as to promote drainage by the piles, as described below.

As illustrated in Figures 3 to 6, the pile 2 is a linear support structure, such as a pillar, or a column comprising a first portion 21 to be stuck in the ground and a second portion 22 projecting above the ground and intended to retain the terrain 5 on a height equivalent to the difference in altitude between the upstream levels 502 and downstream 501. The intermediate panels 3 are not plugged in, or only on a shallow depth. The section of the pile 2 allows to insert it into a hole 6 of circular shape (FIG 9) made in the field. The bore may be cased, that is to say that a tube not shown may be housed temporarily in the bore to retain the soil before the introduction of the pile 2.

Returning to Figures 1 and 2, the pile 2 consists of a main body of reinforced concrete 201, providing structural safety, traversed from top to bottom by a longitudinal opening 26. Openings

transverse 27 quasi-horizontal or possibly oblique are distributed regularly and radially in the main body 201. ensure the flow of water in both directions between the drainage ring 202 and the longitudinal opening 26 which serves as a collector for the drainage water, as will be seen below. A draining crown 202 may surround the main body 201. The section of the reinforced concrete main body 201 is prefabricated in a monolithic manner and does not require any resumption of concreting.

The absence of resumption of concreting makes it possible to avoid weak points where the reinforcement is particularly exposed to the risk of corrosion. This configuration makes it possible durably to ensure the structural safety of the retaining wall 1. However, concreting reversals may be provided for particular embodiments within the scope of the invention.

In the embodiment of Figure 2, the section of the main body of reinforced concrete 201 is provided on its two lateral faces 205 of crows 25 on which abutment panels 3 interpose. a projection, forming a flange on the front face of the pile 2, and preferably extending continuously from the top to the bottom of the pile. In a non-illustrated embodiment, the crows could extend only over a portion of the height of the pile, for example only on the first portion 21 projecting, or on one or more segments of this first portion 21.

The support of the spacer panels 3 on the crows 25 is exclusively by compressed concrete concrete contact on the bearing surface 251 crows 25 and requires no bonding armature. This configuration is therefore optimal from the point of view of sustainability.

A waterproof membrane 252 may be inserted into the concrete of the main body of reinforced concrete 201 so as to extend vertically between the raven 25 and the spacer panels 3. This waterproof membrane 252 has the function of preventing any seepage water to the right of the bearing surface 251 between the crunches 25 of the main body 201 and the intermediate panels 3.

The biased shape of the bearing surfaces 251 on the upstream face of the crows 25 facilitates the projection of the concrete forming the panels

tabs 3.

In the case of secant piles (FIG 1), the crows 25 can be removed and the section of the reinforced concrete main body 201 is adapted. The crows 25 are replaced by an extension of the draining crown 202. This configuration allows the realization of secant piles without drilling in the structural concrete of the main body 201.

The drainage ring 202 is made of draining material, for example draining concrete. It ensures the drainage of the water around the pile to the openings 27 and to the longitudinal hole acting as a collector. Even if a portion, for example the bottom of the draining crown, is clogged with sediments, the water still penetrates through the numerous transverse openings 27 towards the longitudinal opening 26 of relatively large diameter and therefore unlikely to occur. butcher.

This draining material can be fixed to the main body 201 of the pile during prefabrication, that is to say before the blocking with the main body of the pile 201. In another embodiment, this draining material is put in place after the positioning of the main body 201 in the borehole 6, for example after removal of the casing.

The water flows through the sections of draining material around the piles, before entering through the lateral drainage openings 27 in the longitudinal opening 26 which thus serves as a collector for the water from the draining ring 202 The longitudinal opening 26 preferably has a diameter of between 10 and 30 cm, which makes it possible to reduce the risk of obstruction by sediments. The longitudinal opening 26 also allows cleaning (for example in air or water under pressure, or with a cleaning tool) during the entire period of use of the pile.

The longitudinal opening 26 allows inspection control, for example visual, throughout the duration of use of the pile thus ensuring safety and durability of the structure.

The longitudinal opening 26 also pumping the collected water during the establishment of the wall or later.

The longitudinal opening 26 can also be used as a stencil for the precise positioning and centering of the piles in the boreholes. The shape of the longitudinal opening may be circular, square, oval or polygonal.

In the final stage, the longitudinal opening 26 is provided with a removable closure cover 261 to prevent infiltration of water or soil into the pile, while ensuring a durable access window 260 in its the top part.

The radial transverse openings 27 between the draining ring and the longitudinal opening 26 may have a circular cross section, oval, square or polygonal, with a maximum diameter of between 1 and 5 cm. The number of openings is between 1 and 100 per linear meter of pile 2, preferably between 6 and 60, for example between 9 to 20. This relatively large number provides redundancy and ensures drainage even if one or more openings are clogged. The radial transverse openings 27 are distributed over the entire length of the pile (FIGS 3 and 5). In the case of piles injected into the portion stuck in the ground 22, the radial transverse openings 27 are not positioned only on the second portion of the pile 22 (Fig 7). The transverse openings 27 are only provided on the upstream face and

possibly on the lateral faces of the pile. The downstream face is devoid of such openings to prevent the discharge of water on the front of the wall. In a variant, openings 27 are also provided in the plugged portion 21 of the downstream face.

In the case of a draining ring 202 made in the factory with draining material, it is possible to improve the drainage system by covering the draining crown with a geotextile type jacket, in the factory or just before the introduction. of the pile in the borehole. This geotextile type shirt 207 makes it possible to prevent any penetration of fine elements of the soil into the draining crown 202. Such

configuration makes it possible to limit the risk of clogging of the draining ring 202 and to reduce the cleaning work of the longitudinal opening 26 during the service life.

Referring to Figure 5, the draining piles 2 of the invention can permanently suppress any hydrostatic pressure acting on the second projecting portion 22 of the retaining wall. In the usual case, the water is drained and collected in the drainage zone 264, situated between the upstream level of the land 502 and the temporary water level 263 inside the longitudinal opening 26, to be infiltrated naturally. in the ground in the infiltration zone 265, situated between the temporary water level in the longitudinal opening 263 and the level of the water table 266. An opening 28 can be provided on the downstream face of the pile 2 in order to act as overflowing overflow in the case of very important water inflow. This opening 28 is preferably located slightly below the downstream level of the ground 501. A single opening on the downstream face of the pile is sufficient. If fine elements of the ground 5 were to be introduced into the drainage ring 202, they would be transported by the flow of water to the longitudinal opening 26 and sedimentait the bottom of it, without disturbance drainage system. This configuration of the drainage system makes it possible to avoid any barbican (local penetrations of the supports on the projecting height 22 to annihilate the hydrostatic pressure which acts on the support). In addition to being less effective than the stake of the invention, barbacans are a source of unsightly drips creating a

proliferation of vegetation and moss on the visible side of the wall. These water drips also lead to permanent moisture in the concrete, increasing the risk of concrete frost damage in winter conditions, or the formation of ice on the front face or ice on the road surface.

In the embodiment of Figure 2, the spacer panels 3 are made of shotcrete or cast in place, or prefabricated concrete elements. Depending on the quality of the ground, the panels may consist of unreinforced concrete, fiber concrete or reinforced concrete. Interlayer panels 3 may have a section

slightly arched, arch-shaped or flat downstream surface. The spacer panels 3 are put in place or made after the positioning of the piles 2, as and when the excavation. Field 5 must be freestanding for the short time between

the excavation of a portion of slope and the realization of the panel that supports this portion. This temporary stability of the terrain 5 depends mainly on the mechanical properties of the ground 5, possible water inflow, the spacing of the piles 206 and the height of the excavation step. The last two parameters are thus chosen and adjusted case by case according to the mechanical properties of the ground 5.

The risks of water coming in are greatly reduced by the presence of the draining collector passing through the piles 2 (draining crown 202, radial transverse openings 27 and longitudinal opening 26), already effective during the production of the panels 3.

The draining retaining wall 1 can operate without anchors. However, as illustrated in FIGS. 5 and 6, in the case of a terrain 5 of very poor quality, or of large vertical loads acting on the upstream level of the ground 502, it is possible to connect the pile heads by a sill 7 horizontal reinforced concrete cast in place. This sill can optionally be provided with tie rods 8.

Such sill 7 can also be considered without anchors 8. It increases the static redundancy of the system and provide structural safety even in case of rupture of a pile 2.

In the case of a support located downstream of a traffic lane, the sill 7 can also serve as a foundation and diffusion of shock forces in a vehicle restraint system, for example for sliding rails. security.

The prefabrication of the piles 2 guarantees a high quality and a better regularity of the concrete, a more precise positioning of the frame and allows an integral visual control of each pile and its longitudinal opening 26 as drainage collector, before its implementation. implemented. Potential defective piles can be eliminated even before they are transported to the site.

The length of the pile, equivalent to the sum of the length of the protruding portion 22 and the stub portion 21, is preferably between 4 meters and 12 meters. The diameter of the pile 23 is preferably between 40 and 150 cm.

The pile preferably has a substantially identical cross section 24 along the two portions 21, 22. The plugged portion 21 of the pile is of equal length or less than the portion 22 projecting; in one embodiment

Preferably, the length of the plugged portion represents between 20 and 50% of the total length of the pile, preferably between 30 and 50%, of

preferably at least two meters.

The pile 2 is configured to work in bending. Its T-shaped or mushroom cross-section is structurally optimal because it has an increased section of concrete in the compressed area. In addition, the horizontal stirrups are positioned optimally, perpendicular to the facing of the retaining wall. They are thus more effective than the circular pile calipers.

This configuration allows not only to take up the vertical loads and transverse loads directed towards the edges, but it also allows to have two surfaces 251 of vertical supports, when the pile is retained in a drilling field, for the retention of ends of two adjacent panels.

The downstream face 204 of the pile 2 may incorporate a fastening system 40 of facings 4 described below.

The retaining wall 1 may comprise a prefabricated concrete facing 4, bound to the front of the piles 204 for example by a fastener 40, as shown in Figures 1 and 2. The facing may be used for aesthetic purposes particularly when the wall runs along traffic routes or is located in urban areas. The shape of the siding 4 is free. It can be rectilinear, polygonal or rounded. Alternatively or additionally, the facing 4 can be operated functionally. For example, the cladding 4 may incorporate public lighting, be green, include photovoltaic or solar thermal panels, or works of art or billboards. The retaining wall 1 lends itself not only to sustainable use along the edges of roads or railroads to large

attendance, but it also allows a quick implementation and suitable for many applications. Depending on the quality of the ground 5 and the admissible deformations of the retaining wall 1, the section of the pile 2 may be equipped with injection pipes 10. These pipes allow to inject from the top of the pile and through this last, a grout or a fine mortar 101 which spring on the outer surface of the first portion 21, in order to at least partially fill the void left by the withdrawal of the casing provisional casing (Figures 7 to 9). This stabilizes the foot of the pile, especially in the case of a stable ground that would not close around the plugged portion of the pile.

In such a case, the section of the pile can be adapted in the stub portion 21 by replacing the draining crown 202 (which would in any case be filled by the grout) with structural concrete of the central body 201 (FIG 9). . The cross-section of the projecting portion 22 of the piles remaining substantially identical (Fig. 8) to that of the basic variant.

The injection pipes 10 may be arranged in the section of the main body 201 or in the longitudinal opening 26. [0075] In the case of the variant with injection pipes, the longitudinal opening 26 is filled in. the staked portion of the pile 21 and

the evacuation of the water is done exclusively by the downstream opening of water evacuation 28.

The mounting method of the retaining wall comprises drilling at least two drill holes 6 in the ground 5. The drilling is either secant or spaced from each other in the variant comprising panels. 3. Drilling may be cased. In the case of a wet ground, the boreholes 6 fill with water up to the groundwater level.

Draining piles 2 are then inserted into these holes. The water enters the longitudinal opening 26 through the transverse openings 27. If necessary, it can be pumped through the top of the opening 26 to dry the borehole and the surrounding terrain.

In the case of a cased bore, the tube is removed.

The free space around the pile is optionally filled with a draining material, or with a grout injected by the openings 10. Once the piles have been inserted and the ground

if dry, an intermediate panel can be made or placed between these piles, in the variant of Figure 2. This panel can be made on site by spraying concrete, pouring, or by placing a concrete structure. It relies in particular on the surfaces 251 of vertical supports of the piles.

Once the panel is made, the implementation of the retaining wall can be continued by the realization of a new bore adjacent to one of the piles. Once the drilling is done, a new pile 2 can be inserted in this bore so as to allow the realization of a panel between the new pile and the adjacent pile.

The longitudinal opening 26 can be exploited after the establishment of the pile 2 and during the entire period of operation of the wall for example for the following purposes:

-pumping water to dry the land, for example continuously or intermittently;

inspection of the longitudinal openings 26 to check that they are not obstructed, for example by means of a camera; -in case of obstruction, cleaning the longitudinal opening 26 and the transverse openings 27 for example with air or compressed water.

Reference numbers used in the figures

Draining retaining wall

Prefabricated concrete drainage pile

Main reinforced concrete body

Draining crown

Rear of the pile

Front of the pile

Lateral face of the pile

Pile spacing

Geotextile shirt

Stake portion stuck in the field (first portion)

Stake portion of the pile holding the ground (second portion)

Diameter of the pile

Raven

Bearing surface

Waterproof membrane

Longitudinal opening

Access window to the longitudinal opening

Closure lid of the longitudinal opening

Water level range in the longitudinal opening

Temporary water level in the longitudinal opening

Drainage area

Infiltration zone

Groundwater level

Almost horizontal radial transverse openings

Downstream opening of water evacuation

Water collecting pipe

Intermediate panel

Facing

Fastening means of the cladding

Ground

Final downstream level of the land

Definitive upstream level of the land

Drilling

ledger

Anchor

Injection pipe

Fine grout or mortar to fill the void left by the removal of the temporary casing from the borehole

Filling the longitudinal opening

Claims

claims

1. Retaining wall (1) comprising:

a plurality of prefabricated concrete piles (2) at least 4 meters long made monolithically without resurfacing, each pile (2) comprising a first portion (21) stuck in a borehole (50) in a field ( 5) and a second protruding portion (22) for retaining the land (5) upstream, the diameter (23) of said piles being between 40 and 150cm; characterized by: at least a first opening (27) transverse between the rear (201) of at least one pile and the longitudinal opening, for the drainage of water upstream of the wall;

a longitudinal opening (26) passing through said at least one pile from one side to the other, and intended to collect the water drained through the first opening.

2. Retaining wall according to claim 1, comprising intermediate panels (3) between said piles, intended to retain the ground (6),

3. Retaining wall according to claim 2, the piles comprising vertical crows on each of the two opposite lateral sides, so as to form a bearing surface (251) for retaining said intermediate panels (3).

4. retaining wall according to one of claims 1 to 3, at least one said pile (2) having at least one transverse opening (27) between at least one side face (202) of the pile and the longitudinal opening, to the flow of water.

5. retaining wall according to one of claims 1 to 4, said at least one pile (2) being free of transverse openings on its front face.

6. Retaining wall according to one of claims 1 to 4, said at least one pile (2) being devoid of transverse openings on its front face, with the exception of at least one overflow opening (28). ) on the first portion (21).

7. retaining wall according to one of claims 1 to 6, comprising a draining ring (202) partially surrounding at least one pile (2).

8. Retaining wall according to claim 7, the draining ring (202) being fixed to the pile (2).

9. retaining wall according to one of claims 1 to 8, comprising a geotextile jacket (207) around the first portion (21) of said piles in said boreholes.

10. Retaining wall according to one of claims 1 to 8, at least one said pile having injection holes (10) for injecting a slurry or a mortar around the pile.

1 1. Retaining wall according to one of claims 1 to 10, at least one said pile (2) comprising a waterproof membrane (252) inserted into one of the lateral sides of the pile.

12. Retaining wall according to one of claims 2 to 1 1, said spacer panels (3) being cast or projected on site.

13. Retaining wall according to one of claims 1 to 12, comprising a cladding (4) prefabricated linked to said piles.

14. retaining wall according to one of claims 2 to 13, said intermediate panel or said facing comprising an illumination, a photovoltaic panel, a vegetated surface and / or an advertising or artistic surface.

15. Supporting wall according to one of claims 1 to 14, comprising a sill (7) above the piles and for securing several piles.

16. Pre-cast concrete monolithic pile (2) for a retaining wall (1) according to one of claims 1 to 15, at least 4 meters long, provided with a non-circular section (24) with a maximum diameter (23) between 40 and 150cm

characterized by

at least a first opening (27) transverse between the rear (201) of at least one pile and the longitudinal opening for draining the water upstream of the wall;

A pile according to claim 16, provided with a square or rectangular section (24) and comprising a vertical crest (25) of each of the two opposite lateral sides, so as to form a bearing surface (251) for retaining intermediate panels (3).

18. The pile according to one of claims 16 to 17, comprising at least a second opening (27) transverse between at least one side face (202) of the pile and the longitudinal opening for drainage of water.

19. A method of mounting a retaining wall, comprising the following steps:

drilling at least two holes (50) for drilling; inserting a drilling pile (2) according to one of claims 16 to 19 in each said hole (50);

pumping water through said longitudinal opening (26) to dry the ground;

construction or assembly of intermediate panels between the piles.