RETAINING WALL WITH PREFABRICATED PILES AND PILE FOR SUCH A WALL

Description

Technical field

[0001] The present invention relates to a retaining wall comprising prefabricated concrete piles. State of the art

[0002] The construction of roads, railways, buildings or any other type of structure generally requires the reshaping of the natural ground surface, often involving the creation of embankments.

[0003] The maximum slope of the embankments depends on the mechanical properties of the soil and leads to horizontal ground areas of approximately 1.5 times the height of the embankment.

[0004] These significant rights-of-way are often incompatible with cadastral boundaries or existing or planned adjacent works.

[0005] It is technically possible to limit these footprints by building artificial retaining walls. Depending on the specific conditions of each project, these can be, for example: concrete or natural stone gravity walls L-shaped retaining walls, consisting of a reinforced concrete sole and facing concrete or natural stone buttress walls Berlin walls nailed or anchored walls diaphragm walls bored piles reinforced earth prefabricated concrete elements consisting of a facing and a rear anchor-shaped retaining system a stack of modular prefabricated elements etc.

[0006] Most of these types of supports can be stabilized by anchor rods sealed in the ground.

[0007] Each type of support has its advantages, but also its disadvantages which may be, for example, the need for temporary or permanent rights-of-way or supports, an impossibility of monitoring the execution, insufficient durability, significant consumption of materials incompatible with the principles of sustainable development, an impossibility of achieving effective drainage, insufficient rigidity and therefore risks of settlement of adjacent structures, and an excessively long construction time.

[0008] Thus, in the case of gravity walls made of unreinforced concrete or natural stone, stability is ensured exclusively by the wall's own weight. Gravity walls are a robust and durable system, but they have the disadvantage of requiring temporary rights-of-way or supports during their construction. This type of support also requires a significant quantity of materials, which is incompatible with the criterion of saving natural resources for sustainable development.

[0009] L-shaped retaining walls, consisting of a reinforced concrete footing and facing, ensure their stability thanks to the weight of the ground above the footing. This type of wall must be reinforced to withstand the stresses generated by the ground. Like gravity walls, this type of retaining wall has the disadvantage of requiring temporary supports or supports during their construction. In addition, recent studies and accidents have highlighted a risk of corrosion damage to the main reinforcement at the location of the concreting between the footing and the facing. This type of damage is particularly harmful, as it causes a sudden and abrupt failure of the facing, without any observable preliminary signs.

[0010] Another example of a self-supporting precast concrete retaining wall is described in patent US7001110. Such a wall has a visible face and a face against which the ground that the wall is intended to retain rests. In this patent, the retaining wall is connected to the portal frame of a tunnel. This type of precast retaining wall significantly reduces the installation time compared to walls cast in place. The design, dimensioning and application of this wall, however, remains limited to a tunnel or bridge wing wall.

[0011] The "Berlin walls" are formed by an alignment of metal profiles fixed vertically in the ground and the gap between two consecutive profiles is filled with elements of wood, prefabricated concrete or shotcrete as the excavation progresses. This type of support has the advantage of a very short construction time and does not require temporary rights of way. However, due to the corrosion of metal profiles, their durability is not guaranteed. They are therefore used for temporary supports, for example to retain the edges of an excavation during a construction site.

[0012] Parisian walls are similar to Berlin walls, but use cast-in-place reinforced concrete piles instead of metal sections.

[0013] A major problem with Berlin and Parisian walls is the accumulation of water that can form behind the facing. To avoid stresses due to hydrostatic pressure, this water is most often evacuated through holes, called weep holes, through the wall. This water flow causes unsightly marks and the proliferation of vegetation and moss on the visible surface of the wall. In addition, this permanent humidity can lead to damage to the concrete facing in the event of frost.

[0014] GB2232701 describes a retaining wall consisting of two rows of pillars with a diameter between 75mm and 300mm sealed with sprayed cement. The front face may be reinforced with steel reinforcement. This document does not provide any solution to the problem of water accumulation behind the wall.

[0015] Other retaining walls made of piles are shown in documents DE 197 46 731 A and CN 106 759 274 A.

[0016] FR2732383A1 concerns a draining formwork panel made of plastic or metal, intended for the formwork of a concrete retaining wall. 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

[0017] An object of the present invention is to provide a retaining wall free, or at least partially free, from the limitations of known retaining walls.

[0018] A particular aim of the invention is to propose a retaining wall and a pile having great adaptability to the situation, great durability and rapid implementation.

[0019] According to the invention, these aims are achieved in particular by means of a retaining wall of claim 1, a pile according to claim 14 and a method according to claim 17.

[0020] This solution has the particular advantage over the prior art of allowing implementation in a single step of the load-bearing structural element and the drainage system.

[0021] Implementation is rapid, requires no excavation and no temporary support. Earth movements are thus reduced to a strict minimum.

[0022] In particular, the precast concrete monolithic pile offers better durability because it is free from weak points created by concreting rework.

[0023] The type of concrete may vary depending on its position in the pile section.

[0024] The longitudinal opening through each pile constitutes a drainage collector that fulfills its role independently. In the event of accidental malfunction of the drainage system of one pile, drainage of the wall can be ensured by the adjacent piles. Compared to conventional drainage systems with horizontal collector, the proposed solution therefore offers very favorable redundancy.

[0025] The flow of water through the longitudinal opening of the piles helps to avoid the appearance of unsightly marks and the proliferation of vegetation on the front faces of the walls and piles, due to an overflow of water accumulated at the back of the wall.

[0026] The implementation does not require a concrete base under the panels.

[0027] This solution is therefore suitable for long-term use along high-volume roads or busy railways, where a service life of more than 50 years is required.

[0028] Depending on the case, the prefabricated piles can be connected at the top by a reinforced concrete beam cast on site, with or without anchor rods.

[0029] The pile of the invention is multifunctional; it serves both as a structural element to retain the upstream ground as well as the intermediate walls; it serves as a collector for drained water; and it allows, as an option, to pump the collected water. Brief description of the figures

[0030] Examples of implementation of the invention are indicated in the description illustrated by the appended figures in which: There figure 1 illustrates a horizontal section of a retaining wall according to the invention, in the case of secant piles; The figure 2 illustrates a horizontal section of a retaining wall according to the invention, for the case of regularly spaced piles bridged by intermediate panels; The figures 3 And 4respectively illustrate a vertical section and an elevation of a retaining wall according to the invention, in the case of regularly spaced piles, without a beam at the pile head; The 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 stringer at the pile head; The figures 7 to 9 respectively illustrate a vertical section and horizontal sections in the upper projecting part and the lower fixed part of a retaining wall according to the invention, for the case of regularly spaced piles. Example(s) of embodiment of the invention

[0031] THE 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 501 and upstream 502 levels. In the case of the figure 1 , the piles 2 are secant. In the case of the figure 2, the piles 2 are regularly spaced and serve as support for intermediate panels 3 which retain the ground at the final stage.

[0032] The center distance 206 of the piles is determined on a case-by-case basis depending on the geometry and properties of the ground 5, as well as any vertical stresses on the ground located upstream of the retaining wall. Preferably, the center distance 206 of the piles is less than 3 meters so as to promote drainage through the piles, as described below.

[0033] As illustrated by the figures 3 to 6, the pile 2 is a linear support structure, such as a pillar, or a column comprising a first portion 21 intended to be driven into the ground and a second portion 22 projecting above the ground and intended to retain the ground 5 over a height equivalent to the difference in altitude between the upstream 502 and downstream 501 levels. The intermediate panels 3 are not driven, or only over a small depth.

[0034] The section of pile 2 allows it to be inserted into a circular borehole 6 ( Fig. 9 ) carried out in the ground. The borehole can be cased, that is to say that a tube not shown can be temporarily housed in the borehole in order to retain the ground before the introduction of pile 2.

[0035] Returning to the Figures 1 and 2, the pile 2 consists of a main body of reinforced concrete 201, ensuring structural safety, crossed from top to bottom by a longitudinal opening 26. Transverse openings 27, almost horizontal or possibly oblique, are distributed regularly and radially in the main body 201. They ensure the circulation 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 drainage ring 202 can surround the main body 201.

[0036] The section of the main reinforced concrete body 201 is prefabricated monolithically and does not require re-concreting. The absence of re-concreting makes it possible to avoid weak points at which the reinforcement is particularly exposed to the risk of corrosion. This configuration makes it possible to ensure the long-term structural safety of the retaining wall 1. Re-concreting may, however, be provided for specific executions within the framework of the invention.

[0037] In the embodiment of the figure 2, the section of the main body in reinforced concrete 201 is provided on its two lateral faces 205 with corbels 25 on which the intermediate panels 3 rest. The term "corbel" refers to a projecting part, forming a rim on the front face of the pile 2, and preferably extending continuously from the top to the bottom of the pile. In an embodiment not illustrated, the corbels could extend only over a portion of the height of the pile, for example only over the first projecting portion 21, or over one or more segments of this first portion 21.

[0038] The support of the intermediate panels 3 on the corbels 25 is achieved exclusively by compressed contact of concrete to concrete on the support surface 251 of the corbels 25 and does not require any connecting reinforcement. This configuration is therefore optimal from the point of view of durability.

[0039] A waterproof membrane 252 can be inserted into the concrete of the main reinforced concrete body 201 so as to extend vertically between the corbel 25 and the intermediate panels 3. This waterproof membrane 252 has the function of preventing any seepage of water at the bearing surface 251 between the corbels 25 of the main body 201 and the intermediate panels 3.

[0040] The slanted shape of the bearing surfaces 251 on the upstream face of the corbels 25 facilitates the projection of the concrete forming the intermediate panels 3.

[0041] In the case of secant piles ( Fig. 1 ), the corbels 25 can be removed and the section of the main reinforced concrete body 201 is adapted. The corbels 25 are replaced by an extension of the drainage crown 202. This configuration allows the creation of secant piles without drilling into the structural concrete of the main body 201.

[0042] The draining ring 202 is made of draining material, for example permeable concrete. It ensures the drainage of water around the pile towards the openings 27 and then towards the longitudinal hole acting as a collector. Even if a portion, for example the bottom of the draining ring, becomes blocked with sediment, the water still penetrates through the numerous transverse openings 27 towards the longitudinal opening 26 of relatively large diameter and therefore unlikely to become blocked.

[0043] This draining material can be fixed to the main body 201 of the pile during prefabrication, i.e. before installation in block with the main body of the pile 201. In another embodiment, this draining material is installed after positioning the main body 201 in the borehole 6, for example after removal of the casing.

[0044] The water flows through the sections of draining material around the piles, before entering through the lateral drainage openings 27 into the longitudinal opening 26 which thus serves as a collector for the water coming from the drainage crown 202. The longitudinal opening 26 preferably has a diameter of between 10 and 30 cm, which reduces the risk of obstruction by sediment.

[0045] The longitudinal opening 26 also allows cleaning (for example with air or pressurized water, or using a cleaning tool) throughout the entire period of use of the pile.

[0046] The longitudinal opening 26 allows for inspection control, for example visual, throughout the entire period of use of the pile, thus ensuring safety and durability of the structure.

[0047] The longitudinal opening 26 also allows the collected water to be pumped out, when the wall is being installed or later.

[0048] The longitudinal opening 26 can also serve as a template for the precise positioning and centering of piles in boreholes. The shape of the longitudinal opening can be circular, square, oval or polygonal.

[0049] At the final stage, the longitudinal opening 26 is provided with a removable closing cover 261 in order to prevent water or earth infiltration into the pile, while durably guaranteeing an access window 260 in its upper part.

[0050] The radial transverse openings 27 between the drainage ring and the longitudinal opening 26 may have a circular, oval, square or polygonal cross-section, 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 and 20. This relatively large number ensures redundancy and makes it possible to guarantee drainage even if one or more openings are blocked.

[0051] The radial transverse openings 27 are distributed along the entire length of the pile ( Fig. 3 And 5 ). In the case of piles injected into the portion embedded in the ground 22, the radial transverse openings 27 are only positioned 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 in order to avoid the discharge of water onto the front of the wall. In a variant, openings 27 are also provided in the inserted portion 21 of the downstream face.

[0052] In the case of a drainage ring 202 manufactured in the factory with drainage material, it is possible to improve the drainage system by covering the drainage ring with a geotextile-type jacket, in the factory or just before the pile is inserted into the borehole. This geotextile-type jacket 207 makes it possible to prevent any penetration of fine soil elements into the drainage ring 202. Such a configuration makes it possible to limit the risk of clogging of the drainage ring 202 and to reduce the cleaning work of the longitudinal opening 26 during the service life.

[0053] Referring to the Figure 5 , the draining piles 2 of the invention make it possible to permanently eliminate 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, located between the upstream level of the ground 502 and the temporary water level 263 inside the longitudinal opening 26, to be naturally infiltrated into the ground in the infiltration zone 265, located between the temporary water level in the longitudinal opening 263 and the level of the water table 266.

[0054] An opening 28 may be provided on the downstream face of the pile 2 in order to act as an overflow in the event of very significant water inflows. 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.

[0055] If fine elements of the ground 5 were to enter the drainage ring 202, they would be transported by the flow of water to the longitudinal opening 26 and would sediment at the bottom of the latter, without disturbing the drainage system.

[0056] This configuration of the drainage system makes it possible to avoid any weep holes (local drilling of the supports on the projecting height 22 to eliminate the hydrostatic pressure which acts on the support). In addition to being less effective than the pile of the invention, the weep holes are a source of unsightly drips creating a proliferation of vegetation and moss on the visible face of the wall. These water drips also lead to permanent humidity of the concrete increasing the risks of damage from freezing of the concrete in winter conditions, or of formation of icicles on the front face or ice on the roadway.

[0057] In the embodiment of the figure 2, the infill panels 3 are made of shotcrete or cast-in-place concrete, or prefabricated concrete elements. Depending on the quality of the ground, the panels may be made of unreinforced concrete, fiber-reinforced concrete or reinforced concrete. The infill panels 3 may have a slightly arched, vault-shaped section or a flat downstream surface.

[0058] The intermediate panels 3 are put in place or made, after the positioning of the piles 2, as the excavation progresses. The ground 5 must be self-stable during the short period of time between the excavation of a portion of the slope and the construction of the panel which supports this portion. This temporary stability of the ground 5 depends mainly on the mechanical properties of the ground 5, any water ingress, the spacing of the piles 206 and the height of the excavation stage. The last two parameters are therefore chosen and adjusted from case to case according to the mechanical properties of the ground 5.

[0059] The risks of water ingress are greatly reduced by the presence of the drainage collector crossing piles 2 (drainage crown 202, radial transverse openings 27 and longitudinal opening 26), already effective during the construction of panels 3.

[0060] The draining retaining wall 1 can operate without anchors. However, as illustrated in the figures 5 And 6 , in the case of very poor quality ground 5, or significant vertical loads acting on the upstream level of the ground 502, it is possible to connect the pile heads by a horizontal beam 7 made of reinforced concrete cast in place. This beam can, as an option, be fitted with anchor rods 8.

[0061] Such a stringer 7 can also be considered without anchor rods 8. It makes it possible to increase the static redundancy of the system and to ensure structural safety even in the event of failure of a pile 2.

[0062] In the case of a support located downstream of a traffic lane, the beam 7 can also serve as a foundation and diffusion of impact forces in a vehicle restraint system, for example for safety barriers.

[0063] The prefabrication of the piles 2 guarantees high quality and better regularity of the concrete, more precise positioning of the reinforcement and allows a complete visual inspection of each pile and its longitudinal opening 26 as a drainage collector, before its implementation. Any defective piles can thus be eliminated even before their transport to the construction site.

[0064] The length of the pile, equivalent to the sum of the length of the projecting portion 22 and the fixed portion 21, is preferably between 4 meters and 12 meters. The diameter of the pile 23 is preferably between 40 and 150 cm.

[0065] The pile preferably has a substantially identical cross-section 24 along the two portions 21, 22.

[0066] The inserted portion 21 of the pile is of a length equal to or less than the projecting portion 22; in a preferred embodiment, the length of the inserted portion represents between 20 and 50% of the total length of the pile, preferably between 30 and 50%, preferably at least two meters.

[0067] Pile 2 is configured to work in bending. Its T-shaped or mushroom-shaped cross-section is optimal from a structural point of view because it has a larger concrete cross-section in the compressed zone. In addition, the horizontal stirrups are optimally positioned, perpendicular to the facing of the retaining wall. They are therefore more efficient than the stirrups of circular piles.

[0068] This configuration not only allows vertical loads and transverse loads directed towards the edges to be taken up, but it also allows two vertical support surfaces 251 to be available, when the pile is retained in a borehole in the ground, for the retention of the ends of two adjacent panels.

[0069] The downstream face 204 of the pile 2 can integrate a fixing system 40 of facings 4 described below.

[0070] The retaining wall 1 may comprise a prefabricated concrete facing 4, linked to the front of the piles 204 for example by a fixing 40, as illustrated by the Figures 1 and 2 . The facing can be used for aesthetic purposes, especially when the wall runs along traffic routes or is located in urban areas. The shape of the facing 4 is free. It can be rectilinear, polygonal or rounded.

[0071] Alternatively or additionally, the facing 4 may be used functionally. For example, the facing 4 may incorporate public lighting, be planted, include photovoltaic or solar thermal panels, or even works of art or advertising panels.

[0072] Retaining wall 1 is not only suitable for long-term use along busy roadsides or railways, but also allows for rapid implementation and is suitable for many applications.

[0073] Depending on the quality of the ground 5 and the permissible deformations of the Retaining Wall 1, the section of the pile 2 can be equipped with injection pipes 10. These pipes make it possible to inject, from the top of the pile and through the latter, a grout or a fine mortar 101 which emerges on the external surface of the first portion 21, in order to at least partially fill the void left by the removal of the temporary casing of the borehole ( figures 7 to 9 ). This helps to stabilize the base of the pile, particularly in the case of stable ground which does not close around the embedded portion of the pile.

[0074] In such a case, the section of the pile can be adapted in the fixed portion 21 by replacing the draining crown 202 (which would in any case be filled by the grout) with structural concrete from the central body 201 ( Fig. 9 ). The cross-section of the projecting part 22 of the piles remaining practically identical ( Fig. 8 ) to the basic variant.

[0075] The injection pipes 10 may be arranged in the main body section 201 or in the longitudinal opening 26.

[0076] In the case of the variant with injection pipes, the longitudinal opening 26 is filled in the embedded portion of the pile 21 and the water is evacuated exclusively through the downstream water evacuation opening 28.

[0077] The method of assembling the retaining wall comprises drilling at least two boreholes 6 in the ground 5. The boreholes are either intersecting or spaced apart from each other in the variant comprising intermediate panels 3. The boreholes may be cased.

[0078] In the case of wet ground, the boreholes 6 fill with water up to the level of the water table.

[0079] The drainage piles 2 are then inserted into these boreholes. Water enters the longitudinal opening 26 through the transverse openings 27. If necessary, it can be pumped from the top of the opening 26, in order to dry out the borehole and the surrounding ground.

[0080] In the case of cased drilling, the tube is removed.

[0081] The free space around the pile is possibly filled with a draining material, or with a grout injected through the openings 10.

[0082] Once the piles have been inserted and the ground possibly dried out, an intermediate panel can be made or placed between these piles, in the variant of the figure 2 This panel can be made on site by spraying concrete, by pouring, or by placing a concrete structure. It is based in particular on the vertical support surfaces of the piles.

[0083] Once the panel has been completed, the implementation of the retaining wall can continue by drilling a new borehole adjacent to one of the piles. Once the borehole has been completed, a new pile 2 can be inserted into this borehole so as to allow the construction of a panel between this new pile and the adjacent pile.

[0084] The longitudinal opening 26 can be used after the pile 2 has been installed and throughout the entire operating life of the wall, for example for the following purposes: pumping water to dry the ground, for example continuously or intermittently; inspecting the longitudinal openings 26 to check that they are not obstructed, for example using a camera; in the event of obstruction, cleaning the longitudinal opening 26 and the transverse openings 27, for example using compressed air or water. Reference numbers used in the figures

[0085] 1Drainage retaining wall 2Precast concrete drainage pile 201Main body in reinforced concrete 202Drainage crown 203Rear of the pile 204Front face of the pile 205Side face of the pile 206Pile spacing 207Geotextile sleeve 21Portion of the pile driven into the ground (first portion) 22Protruding portion of the pile retaining the ground (second portion) 23Pile diameter 25Corbel 251Support surface 252Waterproof membrane 26Longitudinal opening 260Access window to the longitudinal opening 261Closing cover of the longitudinal opening 262Water level range in the longitudinal opening 263Temporary water level in the longitudinal opening 264Drainage zone 265Infiltration zone 266Water table level 27Near-horizontal radial transverse openings 28Downstream water drainage opening 29Water collector pipe 3Inserted panel 4Facing 40Facing fixing means 5Ground 501Definitive downstream level of the ground 502Upstream levelfinal ground 6Drilling 7Sill 8Anchor rod 10Injection pipe 101Grout or fine mortar to fill the void left by the removal of the temporary casing of the borehole 11Filling of the longitudinal opening

Claims

1. Retaining wall (1) comprising: a plurality of prefabricated concrete piles (2) of at least 4 meters in length, formed monolithically without any casting joint, each pile (2) being composed of a main body (201) and comprising a first portion (21) embedded in a borehole (50) in a soil (5) and a second protruding portion (22) intended to retain the upstream soil (5), the diameter (23) of said piles preferably ranging from 40 to 150 cm, at least one pile further comprising substantially horizontal or optionally oblique transverse openings (27) radially distributed in the main body (210), intended for draining water from the upstream side of the wall and located between the rear side (201) of at least one pile and a longitudinal opening (26) intended to collect the water drained through the transverse openings (27), characterized in that the longitudinal opening (26) passes entirely through said at least one pile (2) from top to bottom.

2. Retaining wall according to claim 1, wherein the number of transverse openings (27) is comprised between 1 and 100 per linear meter of pile (2).

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

4. Retaining wall according to claim 3, wherein the piles comprise vertical projections on each of their two opposite lateral sides, so as to form a bearing surface (251) for retaining said intercalary panels (3).

5. Retaining wall according to any one of claims 1 to 4, wherein at least one said pile (2) comprises at least one transverse opening (27) extending between at least one lateral face (202) of the pile and the longitudinal opening, intended for water flow.

6. Retaining wall according to any one of claims 1 to 5, wherein said at least one pile (2) is free of transverse openings on its front face.

7. Retaining wall according to any one of claims 1 to 5, wherein said at least one pile (2) is free of transverse openings on its front face, except for at least one overflow opening (28) on the first portion (21).

8. Retaining wall according to any one of claims 1 to 7, comprising a drainage ring (202) partially surrounding at least one pile (2), such that the transverse openings (27) enable bidirectional water flow between the drainage ring (202) and the longitudinal opening (26), which serves as a collector.

9. Retaining wall according to claim 8, wherein the drainage ring (202) is fixed to the pile (2).

10. Retaining wall according to any one of claims 1 to 9, comprising a geotextile sleeve (207) around the first portion (21) of said piles within said boreholes.

11. Retaining wall according to any one of claims 1 to 9, wherein at least one said pile comprises injection holes (10) for injecting grout or mortar around the pile.

12. Retaining wall according to any one of claims 1 to 11, wherein at least one said pile (2) comprises a waterproof membrane (252) inserted into one of the lateral sides of the pile.

13. Retaining wall according to claims 3 and 4, wherein said intercalary panels (3) are cast or sprayed on site.

14. Retaining wall according to any one of claims 1 to 13, comprising a prefabricated facing (4) connected to said piles.

15. Retaining wall according to any one of claims 3, 4 and 14, wherein said intercalary panel or said facing comprises lighting, a photovoltaic panel, a vegetated surface, and / or an advertising or artistic surface.

16. Retaining wall according to any one of claims 1 to 14, comprising a capping beam (7) positioned above the piles and enabling the connection of several piles together.

17. Method for assembling a retaining wall (1) according to any one of claims 1 to 16, comprising the following steps: drilling at least two boreholes (50); inserting a bored pile (2) into each said borehole (50); pumping water through said longitudinal opening (26) in order to drain the soil; producing or installing intercalary panels between the piles (2).