JP4651328B2 - Tubing burial method - Google Patents

Description

  The present invention relates to a tubular body embedding method that can be suitably used for laying a large-diameter tubular body. More specifically, the present invention relates to a tubular body embedding method capable of preventing the tubular body from being lifted on the ground having a high groundwater level or in the event of an liquefaction of the ground at the time of an earthquake.

  Generally, when embedding a large-diameter tubular body in the ground, it is necessary to dig a large amount of the original ground, especially in the ground where the groundwater level is high, or during the liquefaction phenomenon of the ground when an earthquake occurs, In order to resist, it is necessary to embed a tubular body deeply and secure a large amount of soil covering. For this reason, excavation of buried trenches requires excavation and transportation of a large amount of earth and sand, which has the problem that the construction cost increases and the construction period is prolonged.

  Also, in burying large-diameter tubular bodies, construction is often performed by driving a sheet pile to prevent the collapse of the ground and maintain the excavation groove. In that case, after the tubular body is laid and backfilled with the backfill material, the sheet pile is generally pulled out, but because the earth pressure distribution changes suddenly by pulling out the sheet pile, the tubular body may be deformed, On the ground with a high groundwater level, large buoyancy is generated in the tubular body, which may cause instability. For this reason, it may be necessary to perform compaction using a high-quality soil material such as sand, sandy soil, gravelly soil, or crushed stone as the backfill material.

  In order to improve the above drawbacks, attempts have been made to improve the efficiency of burying work by taking measures to prevent the tubular body from rising and burying the tubular body in a shallow groove. For example, one of the present applicants has proposed a method for embedding underground structures using geotextiles (Patent Document 1). According to this proposal, the earth pressure change at the time of drawing out the sheet pile is reduced, the stability of the tubular body in the ground is increased, and the floating of the tubular body can be effectively suppressed against the liquefaction phenomenon of the ground, Shallow embedding became possible, and the construction period was shortened and the construction cost was reduced. However, there are problems such as troublesome work associated with laying geotextiles and the inability to backfill excavated earth and sand, and there is a need to develop a pipe burying method that is cheaper and has better work efficiency. It was.

Japanese Patent Laid-Open No. 11-101369

  The present invention responds to such a demand, and the object of the present invention is to prevent the floating of the tubular body effectively with respect to the liquefaction phenomenon of the ground by a simple operation. An object of the present invention is to provide a tubular body embedding method effective for shallow embedding of a large-diameter tubular body. Another object of the present invention is that the earth and sand excavated by excavation of the buried trench can be used for backfilling, thus reducing the cost of carrying and disposal of the earth and sand and adversely affecting the environment. Another object of the present invention is to provide a tubular body embedding method that can be prevented.

That is, according to the present invention, when laying a tubular body on a support ground of a groove formed by excavating the ground, a plurality of sandbags integrated with a belt-like or sheet-like long connecting member are The connecting member is placed in contact with the upper part of the tubular body, and at least a part of the plurality of sandbags is placed separately on the support ground on both sides of the tubular body, and this is repeated along the longitudinal direction of the tubular body. A tubular body embedding method is provided, wherein the tubular body is backfilled after being arranged.

  The sandbag is generally placed at a predetermined position in a state filled with a soil material. As the soil material in this case, excavated soil is preferably used. However, after the unfilled sandbag is placed at a predetermined position, and before the backfilling, the soil material having fluidity can be poured into the sandbag at the place of placement to make a sandbag.

  The long connecting member for integrating a plurality of sandbags is preferably a belt-like material or a sheet-like material having a large contact area with the tubular body. The integration of the plurality of sandbags can be performed by connecting them with a belt-like or sheet-like long connecting member. Further, the sandbag can be integrated with the tubular body by surrounding it with a belt-like or sheet-like long connecting member. A geogrid is preferably used as a belt-like or sheet-like long connecting member used for such purposes. The long connecting member is also preferably mounted with a sandbag so as to be in contact with the upper portion of the tubular body in a tensioned state in order to more effectively prevent the floating of the tubular body. In order to make the prevention of the floating of the tubular body more effective, it is also effective to pile up another sandbag not connected by the long connecting member on the sandbag placed above and then backfill it. Is.

  The embedding method for a tubular body of the present invention can be suitably used when a tubular body is laid in a groove formed by excavating the ground into which a sheet pile has been driven. Furthermore, such a sheet pile can be suitably used in a construction method in which it is pulled out after being backfilled with a backfilling material.

  According to the present invention, it is not necessary to excavate the ground greatly even when embedding a large-diameter tubular body, and the floating of the tubular body is effective even in the ground with a high groundwater level or the liquefaction phenomenon of the ground when an earthquake occurs Can be prevented. Moreover, since the burial work is simple and the amount of excavated soil to be transported and discarded is reduced, the construction cost can be reduced and the construction period can be completed in a short period of time.

  Hereinafter, the present invention will be specifically described with reference to the embodiments shown in the drawings.

  FIG. 1 is a cross-sectional view showing a state in which a tubular body 6 is laid in the excavation groove 1 and a sandbag 8 connected by a belt-like long connecting member 7 is placed on the support ground 5 on both sides of the tubular body. is there. In FIG. 1, a predetermined groove width W is secured in the ground 2 at the burial site, the sheet pile 3 is driven into the ground 2, and the ground between the sheet piles 3 on both sides is excavated to form the excavation groove 1. A material having a high supporting force such as sand or crushed stone is poured into the upper portion of the bottom ground 4 of the excavation groove 1 to form a supporting ground 5, and a tubular body 6 is laid thereon. As the tubular body 6, for example, an FRPM pipe, a steel pipe, a ductile cast iron pipe, a concrete pipe or the like is used. In the present invention, the tubular body 6 can be applied to various diameters, for example, a large diameter such as a diameter of 100 to 400 cm.

  Next, the sandbag 8 connected by the long connecting member 7 is placed on the support ground 5 so that the long connecting member 7 abuts on the upper part of the tubular body 6 and the sandbag 8 is located on both side surfaces of the tubular body 6. To do. As shown in FIG. 3, these are arranged at predetermined intervals along the longitudinal direction of the tubular body 6. In this case, of course, they may be continuously arranged without a gap. When placing the sandbag 8, it is preferable to place the long connecting member 7 so as to contact the upper portion of the tubular body 6 in a tensioned state in order to effectively prevent the tubular body from rising. Moreover, it is preferable that the center of gravity of the sandbag 8 is positioned below the center of the tubular body 6. For this purpose, it is necessary to adjust the length of the long connecting member 7 appropriately.

  The long connecting member 7 and the sandbag 8 may be prepared in advance, but as shown in FIG. 2, a hooking portion 11 is provided on the sandbag 8 and the hooking portion is provided at the construction site. The belt-like long connecting member 7 can be connected to the belt-like long connecting member 7 through bundling or the like, and both can be integrated.

  The sandbag 8 is preferably provided with an openable / closable opening, and the excavated soil is filled into the sandbag from the opening at the construction site and the opening is closed. In general, excavated soil causes a liquefaction phenomenon and cannot be used as a backfill material. However, if the excavated soil is used by filling a sandbag, this can be prevented, and operations such as transportation and disposal of excavated soil can be reduced. The sandbags can also be made of building waste materials that are similarly causing problems in disposal, thereby reducing the environmental burden.

  When laying a large-diameter tubular body, the sandbag weight required to prevent ascent will increase, making it difficult to work manually. It is necessary to lift and place the long connecting member portion of the sandbag 8 connected by the member 7. For this reason, the long connecting member 7 needs to have strength enough to withstand the weight of the sandbag in addition to good workability. It is desirable that the sandbag weight be distributed and loaded on the upper surface of the tubular body 6. Therefore, as the long connecting member 7, a rope, belt or sheet can be used. For example, a wide belt or sheet having a width of about 3 to 50 cm is most used. preferable. In consideration of the lifting workability, it is desirable that the two sandbags connected by the long connecting member 7 have substantially the same weight.

  Furthermore, it is desirable that the long connecting member 7 and the sandbag 8 have durability in the ground. Considering these strengths and durability, it is preferable to use polyolefin, aromatic polyester, polyamide, FRP or the like as these constituent materials. Moreover, as the long connection member 7, the steel material (band steel) which carried out the antirust process can also be used.

It is preferable that the weight of the contents filled in one sandbag integrated with the long connecting member is slightly larger than the necessary weight G expressed by the following formula.
G = (UP-S) / n
(In the formula, G is the required weight of the sandbag (ton), U is the levitation force per ton of the tubular body (ton) at the time of soil liquefaction, and varies depending on the type of soil, but the diameter of the tubular body is R (m ) Is approximately represented by U = πR ^2. P is the weight per ton of the tubular body (tons), S is the weight of the top soil per ton of the tubular body (tons), and n is the longitudinal direction of the tubular body. Number of sandbags per meter)

  After placing and arranging the sandbags 8, the backfilling work is finished by putting backfill material into the groove space above the tubular body and backfilling. After completion of the burial work, the sheet pile can be pulled out as needed. Further, the backfill portion can be compacted as necessary. As the backfill material, one or more kinds such as mountain sand, crushed stone, fluidized soil, soil cement, and air mortar can be selected, and backfilling can be performed in two or more different layer configurations.

  FIG. 4 shows another embodiment of the present invention. The sandbag 8 connected by the long connecting member 7 is in contact with the upper part of the tubular body 6, and the sandbag 8 is on both sides of the tubular body 6. After placing on the support ground 5 of the surface, the sandbag 9 that is not connected is placed on the sandbag 8. Since the sandbag 9 can be filled with excavated soil in the same manner as the sandbag 8, the load of the excavated soil treatment can be further reduced and the tubular body floating prevention effect of the sandbag 8 can be further enhanced. Therefore, according to this embodiment, the weight of the contents filled in the sandbag 8 may be slightly reduced. After placing the sandbag 9, the backfilling material 10 is carried back into the upper space of the excavation groove 1 in the same manner as in the embodiment of FIG. Pulling out the sheet pile after completion of the backfilling and compacting the backfilling part can be performed arbitrarily.

  FIG. 5 is a drawing showing a cylindrical sandbag 12 that can be used as a sandbag according to the present invention. An openable / closable opening 13 is provided at the top of the sandbag 12, and a handle 14 serving as a wire attaching portion for lifting with a crane is provided at the side thereof. FIG. 6 is a drawing showing another cylindrical sandbag 15 that can be used as the sandbag of the present invention. Similarly, an openable / closable opening 16 is provided at the upper part of the sandbag 15 and a lifting band 17 extending upward from the lower part is provided. Both can be filled with excavated soil at the work site, and crane work is possible when placing sandbags.

  7 and 8 are drawings showing that the above-mentioned cylindrical sandbag 12 is stacked in two steps on both side surfaces of the tubular body 18 and continuously placed in the longitudinal direction. FIG. 7 is a perspective view, FIG. Is a cross-sectional view. The four sandbags 12 are housed and connected to both ends of the wide endless belt-like geogrid 19, and are placed on the support ground 5 on the side surface of the tubular body 18 in two layers. The geogrid center coupling portion having a double structure is in contact with the upper portion of the tubular body 18 in a tensioned state. In consideration of durability and strength, it is preferable to use a geogrid obtained by stretching a perforated sheet of polyolefin uniaxially or biaxially.

  In the cylindrical sandbag as shown in FIGS. 5 and 6, a very long one, for example, 4 to 50 m long can be used. In this case, as a modification of FIG. 7 and FIG. 8, two unfilled long sandbag bags connected by the same long connecting material at appropriate places as in the sandbag of FIG. 7 (FIG. 8) After placing on both sides of the sandbag, fluid sandy material, such as fluidized soil, fluid soil cement or grout, is injected into the sandbag bag from the openable opening provided at the tip of each sandbag. And by closing an opening part, a long sandbag can be produced in a mounting location. After the sandbag is created, the tubular body can be embedded by backfilling with a backfilling material.

  FIG. 9 is a view showing another sandbag 20 that can be used in the present invention, in which an openable / closable opening 21 is provided in the upper part, and two belt loops 22 are provided in the side part. ing. When the sandbag 20 is placed on the supporting ground, the belt 24 is passed through the belt 22 so that the sandbag is filled with a soil material and the opening is closed, and the two sandbags are wound around the bottom of each sandbag. Connect through. Next, the central portion of the belt 24 is lifted, and the sandbag 20 is transported to the place of placement, and the sandbag 20 is placed on both sides of the tubular body 23 while the belt 24 is in contact with the upper portion of the tubular body 23 as shown in FIG. . After arranging this continuously or repeatedly along the longitudinal direction of the tubular body, the tubular body is buried again by backfilling with a backfilling material.

  FIG. 11 is a drawing showing another example of the embedding method of the present invention. A large recess is provided at the construction site of the support ground 5, a geogrid 27 is laid thereon, and a sandbag 26 is arranged thereon. After the tubular body 25 is placed at the center thereof, the geogrid 27 is folded up from both sides and connected at the upper part of the tubular body, so that the sandbag 26 is placed on the lower part and both sides of the tubular body 25. The plurality of sandbags are connected and integrated together with the tubular body. After such an integrated structure is repeatedly provided along the longitudinal direction of the tubular body, it is similarly backfilled with a backfill material to embed the tubular body.

  The above various tubular body embedment methods can be applied in combination of two or more.

It is drawing which shows an example of the embedding construction method of the tubular body which concerns on this invention. It is drawing which shows an example which connected the sandbag which has a hook part by the elongate connection member. In the example of FIG. 1, it is a perspective view which shows that the sandbag is arranged in the longitudinal direction of the tubular body. It is drawing which shows the other example of the embedding construction method of the tubular body which concerns on this invention. It is drawing which shows an example of the sandbag used by this invention. It is drawing which shows the other example of the sandbag used by this invention. It is a perspective view which shows the other example of the embedding construction method of the tubular body of this invention. It is sectional drawing of the said drawing. It is drawing which shows the other example of the sandbag used by this invention. It is a perspective view which shows the other example of the embedding construction method of the tubular body of this invention. It is sectional drawing which shows the other example of the embedding construction method of the tubular body of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Excavation groove 2 Ground 3 Sheet pile 4 Excavation groove bottom ground 5 Support ground 6 Tubular body 7 Long connecting member 8 Sandbag 9 Sandbag 10 Backfilling material 11 Hook 12 Sandbag 14 Handle 15 Sandbag 17 Lifting belt 18 Tubular body 19 Geogrid 20 sandbag 22 belt loop 23 tubular body 24 belt 25 tubular body 26 sandbag 27 geogrid

Claims (9)

When laying a tubular body on the support ground of a groove formed by excavating the ground, a plurality of sandbags integrated with belt-like or sheet-like long connecting members are connected to the upper part of the tubular body. after at least a portion of the contact, and a plurality of sandbags are placed so as to be positioned separated on a support ground on both sides of the tubular body were repeated sequence along it in longitudinal direction of the tubular body, it fills back method The sandbag is prepared by injecting a fluid soil material into the sandbag bag after placing the unfilled sandbag bag and before backfilling. Tubing burial method. 2. The tubular body embedding method according to claim 1, wherein the plurality of sandbags are integrated with the tubular body by being surrounded by a belt-like or sheet-like long connecting member. The method of embedding a tubular body according to claim 1 or 2, wherein the belt-like or sheet-like long connecting member is a geogrid. The method of embedding a tubular body according to any one of claims 1 to 3 , wherein the long connecting member is in contact with the upper portion of the tubular body in a tensioned state. When laying the tubular body on the support ground of the groove formed by excavating the ground,
A plurality of sandbags integrated with belt-like or sheet-like long connecting members, the long connecting members abut on the upper part of the tubular body, and at least a part of the plurality of sandbags is on the support ground on both side surfaces of the tubular body. The plurality of sandbags are integrated with the tubular body together with the belt-like or sheet-like long connecting member, and this is integrated in the longitudinal direction of the tubular body. A method of embedding a tubular body, wherein the tubular body is back-filled after being repeatedly arranged along. The tubular body embedding method according to claim 5, wherein the belt-like or sheet-like long connecting member is a geogrid. The method for embedding a tubular body according to claim 5 or 6 , wherein the contents of the sandbag are excavated soil. The method for embedding a tubular body according to any one of claims 1 to 7 , wherein the groove is formed by excavating a ground into which a sheet pile is driven. 9. The tubular body embedding method according to claim 8 , wherein the sheet pile is pulled out after being backfilled.

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