CH711908B1 - Self-supporting prefabricated reinforced concrete retaining wall. - Google Patents

Abstract

The invention relates to a self-supporting prefabricated reinforced concrete retaining wall (1), comprising: a wall portion (2) facing upwards and intended to retain an embankment, the wall portion (2) comprising a front face (20). ) intended to be free and a rear face (21) against which the backfill is intended to be pressed; and an anchor element (3) projecting from said rear face and intended to anchor the retaining wall in the embankment, the anchor element (3) comprising a bearing surface (313) parallel to said wall portion (2) and intended to rest against an edge of a foundation (6). This wall allows for reduced excavation compared to a traditional L-shaped retaining wall.

Description

Technical area

The present invention relates to the field of civil engineering and land development. It relates in particular to a self-supporting prefabricated reinforced concrete retaining wall.

State of the art

Each uneven surface (embankment, embankment, trench) tends to move downward under the influence of gravity. The shear resistance of the ground opposes this tendency to move. If the shear strength of the soil is insufficient, the soil gradually or suddenly slips.

[0003] In order to limit this risk, it is necessary to consolidate the embankments or the embankments whose slope is significant. For example, solutions are known for retaining an embankment by means of a retaining wall at the edge of a road or a railroad, for example.

[0004] It is important to ensure that the anchor wall itself remains stationary. To this end, FIG. 8 illustrates an example of a retaining wall 1 of the prior art which is retained in the embankment 61 by means of anchoring cables 64. This anchoring requires a large space behind the wall. The volume to be excavated to place these anchor cables, then to backfill afterwards, is therefore important. This solution is not available when the width available is insufficient to fix the anchor cables.

[0005] Consolidation walls are also known, the stability of which is ensured above all by the own weight of the wall. These walls are called gravity walls. An example is described in patent application FR2566814 which illustrates a prefabricated retaining element for embankments, banks, trenches, shafts, tunnels, etc.

[0006] A weight wall cast in place is necessarily heavy and therefore expensive and not very aesthetic. In this application, the wall is further maintained by means of anchoring reinforcements sealed in the ground. This wall therefore requires a firm ground to retain these anchors. This solution, however, is not suitable when it comes to retaining a backfill of loose earth or rubble in which it is impossible to anchor a reinforcement.

[0007] FIG. 9 illustrates a retaining wall 1 of the prior art with an L-shape. Stability is obtained by the own weight of the wall as well as by the weight of the backfill material on a foot 65 at the square wall 1. These walls have a lighter appearance than gravity walls, and require a reduced mass of concrete. Installation time is reduced by using prefabricated square elements. The width of the foundation required is however important, especially towards the rear, in order to position the foot 65. In addition, it is not possible to plant trees just above the foot of the wall. The angled walls additionally support at most a load of 5 kN for the backfill.

[0008] EP1228275 describes an assembly of concrete panels intended to cover a wall, for example a wall. The panels are retained by means of anchoring elements sealed in the face to be covered. This solution can only be implemented in the presence of a sufficiently strong wall to retain the anchoring elements and the panels.

Another example of a self-supporting prefabricated concrete retaining wall is described in patent US7001110, the content of which is incorporated by reference. Such a wall has an exposed face and a face against which rests an embankment that the wall aims to retain. In this patent, the retaining wall is linked to the portal frame of a tunnel.

The retaining wall is retained by the portico, by a reinforced concrete base, and by an anchoring element projecting from the rear face of the wall. This anchoring element is cantilevered in order to penetrate into the backfill behind the wall. The metal reinforcement of the concrete allows the anchoring element to be linked to the vertical portion of the wall.

[0011] This type of prefabricated retaining wall makes it possible to considerably reduce the implementation time compared to walls cast in place. The durability of the wall, however, remains insufficient for many applications. Sliding and tilting stability and prevention of shear breakage are not optimal. In addition, the risk of the wall degrading, or even collapsing under the weight of soil and water accumulated behind the rear face, increases after a few decades. For these reasons, such prefabricated retaining walls remain little used on the edges of roads or railways with heavy traffic. They are only suitable for applications in which at least one side of the wall is firmly attached to a tunnel frame or other rigid fulcrum. They are not suitable for long walls made up of many juxtaposed walls; the collapse of a wall leads by domino effect that of its neighbors.

[0012] Furthermore, the establishment of this type of wall is difficult, in particular in the case of walls made up of several juxtaposed retaining walls. In this case, it is necessary for the front faces of the different walls to be perfectly aligned in the same plane, for aesthetic reasons but also to avoid the risk of water or earth infiltration between two poorly aligned portions of walls. However, it is difficult to precisely align such walls which, due to their weight, have to be moved by lifting them with a crane. Even if the crane manages to place a wall in the precise location that is desired, the settlement of the soil in the days following installation, or the backfilling of the volume behind the wall, frequently causes displacements which require realignment. A crane must return for this purpose to lift the wall and move it a few inches. It is not uncommon for this new uplift to damage the wall, especially at the junction between the anchor and the retaining wall portion.

An object of the present invention is therefore to provide a prefabricated retaining wall which is easier to install and to align with other walls.

Another object of the present invention is to provide a prefabricated retaining wall of which the sliding stability, the resistance to the risk of ground shearing as well as the durability are improved.

An object of the present invention is also to provide a retaining wall of which the static resistance, the tilting resistance and the punching resistance are greatly improved.

Another goal is to achieve a self-supporting wall, that is to say a wall which must not be anchored to a wall, but which on the contrary makes it possible to retain a backfill in soft earth, rubble, sand or any non-freezing material accumulated behind one face of the wall.

An object of an embodiment of the present invention is also to provide a retaining wall more resistant to corrosion of the reinforcements.

Brief summary of the invention

In order to limit these problems and to achieve the goals of the invention, the self-supporting prefabricated reinforced concrete retaining wall comprises: <tb> <SEP> a wall portion facing upwards and intended to retain an embankment, said wall portion comprising a front face intended to be free and a rear face against which the embankment is intended to be pressed; <tb> <SEP> an anchoring element projecting from said rear face and intended to anchor the retaining wall in the backfill; <tb> <SEP> the anchoring element comprising a bearing surface parallel to said portion of wall and intended to bear against an edge of a foundation.

The support surface parallel to the wall portion allows to support and align the retaining wall against a foundation. This makes it easier to align several adjacent walls. This support also avoids the risk of the retaining wall sliding forward, since it is retained by this support surface against the foundation.

[0020] The bearing surface can be vertical. It is thus possible to rest it against the vertical edge of a foundation that is easy to build.

The bearing surface may be below the level of the bottom of the wall portion when the wall is in place. It is thus possible to rest it against a foundation entirely under the wall and below ground level.

The anchoring element may include a rod (or rod) in a plane oriented substantially vertically and substantially perpendicular to the wall portion; and at least one arm (or leg) extending perpendicular to the plane of the penis, in an upward direction, from the distal end of the penis.

[0023] The arm or arms allow the retaining wall to be anchored, which cannot move forward without having to drag the earth and the materials between the arm or arms and the wall portion.

[0024] The arm or arms can extend in an oblique plane with respect to the wall portion. In this case, the rod has two side faces parallel to each other, perpendicular to the portion of the wall, facing upwards, and in the form of a rectangular trapezoid.

At least one arm of the anchoring element can be curved so as to form an anchoring portion comprising two main faces oriented upwards and a bearing portion comprising two substantially horizontal main faces. The major faces of each portion are the largest faces of that portion. The bearing surface may be formed by one of the faces of this bearing portion, for example by a vertical face facing the wall portion.

[0026] The rod may include an upper edge and a lower edge, substantially horizontal when the retaining wall is in place.

The lower face of the bearing portion is preferably located below the lower face of the penis.

The support portion can be disposed entirely under the lower edge of the rod.

The bearing portion under the rod is preferably long enough to avoid forming an acute angle with the ground or with other elements of the retaining wall. The lower face of this support portion is preferably substantially horizontal and flat when the wall is in place. This reduces the risk of breaking this support portion when the crane sets down the wall.

[0030] In one embodiment, the retaining wall comprises a rod and two arms extending on each side of this rod.

The width of the wall portion can be between 200 and 300cm. Its height can be between 250 and 600 cm.

[0032] The wall is self-supporting; it holds stably even without being sealed, and can hold an earthen fill that leans against its rear face. Through the anchor element, the weight of the wall and the weight of the backfill both help prevent the wall from sliding forward, tipping and breaking of the soil.

[0033] According to one embodiment, the invention also starts from the observation that the problems of durability and stability of known retaining walls arise in particular from the corrosion of the concrete reinforcement.

Corrosion is in particular due to water infiltration through the concrete; these infiltrations originate in particular from microcracks through the concrete, in particular at the point of connection between the anchoring element and the wall portion. These microcracks are frequently caused during transport of the wall after its manufacture, during its installation and during the shrinkage linked to the hydration of the concrete. The anchoring element is then very stressed and stresses frequently appear at the connection with the wall.

At least one injection pipe may be provided near the junction between said portion of wall and said anchoring element in order to inject a microcement, a mortar and / or a resin to fill any cracks at this location. in concrete.

The wall may include self-adhesive sealing strips to seal the surface of the junction between the wall portion and the anchoring element. Thus, water cannot enter the cracks.

The frame of the wall can be made at least partially in stainless steel.

The concrete can be an ultra-high performance fiber-reinforced concrete (UHPC), which has the advantage of an almost perfect seal, and of great ductility reducing the risk of microcracks.

In order to reduce corrosion, the concrete may include an inhibitor of the calcium nitrate type, for example.

The reinforcing bars can be coated with epoxy, or covered with a protective coating.

The retaining wall may include a metal frame and a plurality of corrosion detectors of this frame. Thus, it is possible to detect corrosion quickly and to replace or repair a portion of wall before it collapses.

Corrosion detectors can be embedded in the thickness of the wall and provided with a radiofrequency interface.

Corrosion detectors can be humidity detectors.

Corrosion detectors can be based on an electrical or electrochemical measurement, a measurement of humidity, or of potential fields.

The retaining wall can be connected to other identical retaining walls, to support a portion of backfill longer than the width of a single wall. It is important to keep the adjacent walls together, so that a valid wall prevents a neighboring wall in poor condition from collapsing, and then dragging it down and down the embankment.

For this purpose, the wall portion may have two side sections facing upwards. At least one of these slices, but preferably both, have a profile which allows tenon-mortise-type retention with an adjacent wall.

The rear face of the wall can also be provided with rails for fixing a retaining plate with an adjacent wall. Rail mounting compensates for variability in clearance between two adjacent walls.

The rear face may include anchor points for fixing retaining cables with an adjacent wall.

We have seen that the microcracks between the wall portion and the anchoring element often occur during transport and the installation of the retaining wall. In order to reduce this risk, according to one aspect, the wall is provided with means allowing it to be lifted and moved without creating tensions or cracks in this zone.

To this end, the rear face of the retaining wall may include anchoring points for lifting the wall, for example by passing a cable through the anchoring point, or by screwing therein a piton allowing a cable to pass. .

At least one anchoring point can be provided on the anchoring element, for example on the upper edge of the anchoring element.

Advantageously, these anchor points make it possible to hold the wall in a balanced manner with the horizontal portion of the wall.

Advantageously, these anchoring points make it possible to hold the wall with the vertical portion of the wall, and a cable retaining the anchoring element.

In order to further reduce the risk of cracks during handling and transport of the wall, there are preferably fixing points on the rear face and on the anchoring element, which allow a frame to be attached to it. to hold the anchoring element during its transport, and to avoid any movement relative to the wall portion. The fixing points advantageously make it possible to fix a rectangular frame held at at least three points to the wall portion and to the anchoring element.

The wall reinforcement is designed so as to further reduce the risk of slits at the interface between the rear face of the wall and the anchoring element. This reinforcement also contributes to the support and the increase of the resistance of the wall. For this purpose, the wall portion preferably comprises a metal frame with elements facing upwards in the form of a U and in the form of an inverted U.

The anchoring element may comprise a metal frame with substantially horizontal elements in the form of a C and in the form of an inverted C.

The retaining wall can include both reinforcing elements in the wall portion and reinforcing elements in the anchoring element. These reinforcing elements can be crossed in order to further secure the portion of the wall and the anchoring element.

In one embodiment, the wall can include several anchoring elements, for example two anchors with, for each, a rod in a vertical plane and one or more arms.

The anchoring element may include a drainage hole. A drainage hole can be parallel to the plane of the wall portion. A drainage hole can pass through the wall portion.

[0060] Drainage can be provided at the rear of a foundation under the retaining wall.

[0061] Drainage can be provided at the rear of the wall portion.

The retaining wall may include a sill, that is to say a concrete beam, for example prefabricated, on the top of the wall. This sill improves the attachment of the retaining wall to the backfill and / or to the adjacent walls.

For the same purpose, the retaining wall may include a sill or a metal plate on the rear face.

Brief description of the figures

Examples of implementation of the invention are indicated in the description illustrated by the appended figures, which illustrate: <tb> <SEP> • Figure 1 a side view of a retaining wall according to one embodiment of the invention. <tb> <SEP> • Figure 2 a top view of a retaining wall according to one embodiment of the invention. <tb> <SEP> • Figure 3 is a top view of two retaining walls according to one embodiment of the invention, linked to one another. <tb> <SEP> • Figure 4 a side view of a retaining wall according to an embodiment of the invention, mounted on a concrete footing as a foundation, and provided with two stringers. <tb> <SEP> • Figure 5 a side view of a retaining wall according to an embodiment of the invention, mounted on a concrete footing as a foundation, and provided with a sill as well as drains. <tb> <SEP> • FIG. 6 is a side view of a retaining wall according to one embodiment of the invention, the reinforcement being shown in dashed lines. <tb> <SEP> • Figure 7 is a sectional view of a retaining wall according to one embodiment of the invention, after its installation. <tb> <SEP> • Figure 8 a sectional view of a retaining wall according to the prior art, after its installation. <tb> <SEP> • Figure 9 a sectional view of a retaining wall according to the prior art, after its installation.

Example (s) of embodiment of the invention

A precast concrete retaining wall 1 is illustrated in side view in Figure 1 and in top view in Figure 2. It generally comprises a wall portion 2 with a front face 20 and a rear face 21 The two faces 20, 21 are preferably mutually parallel and substantially vertical, or in any case oriented upwards, when the wall is installed.

The front face 20 is intended to be visible while the rear face 21 is intended to retain an embankment 61 pressed against this face, as illustrated schematically in Figure 7. This retaining wall 1 is for example intended to retain the earth or rubble from the embankment 61 to prevent them from running down a road 60 or a railway in front of the front face 20. One or more drainage openings 24 may be provided through the portion of wall 2, in order to allow water accumulated behind the wall to pass through the wall and reduce the water pressure on the rear face 21.

The retaining wall 1 is retained on the one hand by its own weight, and on the other hand by at least one anchoring element 3 on the rear face 21 of the wall. In one embodiment, the anchoring element 3 shown from above in Figure 2 has an anchor form with a shank (or rod) 30 and two arms (or legs) 31 which extend laterally on each side. from the distal end of this rod. The rod 30 has two side faces 32, 34 in the form of a rectangular trapezoid, substantially perpendicular to the rear face 21 of the wall, and substantially vertical when the retaining wall 1 is in place. The top slice of this yard is referenced with the number 302 and the bottom slice with the number 301.

The two arms 31 extend in an inclined plane perpendicular to the plane of the rod 30, and oblique. The lower end of these arms 31 forms a support portion 312 curved towards the wall portion 2, and extends partly under the lower edge 301 of the rod in the form of a trapezoid. The lower end 314 of the support portion 312 is therefore flat and linked by obtuse angles to the rest of the anchoring element, which limits the risk of breaking it during transport or when the wall is installed. support. The upper face 318 of the bearing portion 312 is also flat. The length of the bearing portion 312 also makes it possible to reduce the risk of breakage.

The support portion 312 of each arm 31 comprises a substantially vertical support surface 313 to support the wall directly against the vertical edge of a concrete sole as a foundation 6. This arrangement avoids the risk of the wall 1 sliding forward and positioning it precisely in relation to this foundation and in relation to the adjacent walls.

It is also possible to provide the rear face 21 of the wall portion 2 with several anchoring elements 3.

The rear face 21 of the wall portion 2 is further provided with anchor points 210 for lifting the retaining wall by means of a crane for example. The anchoring points allow the introduction of eyebolts, for example spherical or ring eyebolts, for lifting by means of cables or straps. In an advantageous embodiment, four anchoring points 210 are provided on the rear face 21, distributed so as to allow the wall to be lifted with the portion 2 horizontally and with a balanced tension on the four straps or cables. At least one additional anchor point 310 may be provided on the upper edge 302 of the shank or on the upper edge of the arms 31, in order to lift the wall vertically by means of cables or straps linked to the anchor points 210 upper and to this or these anchoring points of the anchoring element.

As illustrated in Figure 2, one or more injection pipes 36 are advantageously provided in order to be able to inject microcement, mortar and / or resin in order to fill any cracks at the level of the attachment between the anchoring element 3 and the rear face 21. One end of each pipe emerges on the rear face 21, or possibly on one of the side faces of the rod 30, in order to allow the injection of microcement, mortar and / or resin under high pressure, for example with a pressure greater than 50 bars, preferably greater than 100 bars. The injection pipe can be provided with perforations allowing the injected product to enter any microcracks in order to fill them.

As illustrated in Figure 2, the risk of introducing water into this area can be further reduced by means of a surface seal, for example by means of self-adhesive sealing strips 33 glued on each side of the rod 30, so as to cover the connection with the dorsal face 21. The width of these bands is advantageously between 15 and 30 centimeters.

The risks of corrosion can be further reduced by manufacturing the retaining wall with ultra-high performance fiber-reinforced concrete (UHPC). This concrete offers the advantage of an almost perfect seal, limiting the risk of water entering through the concrete. Its high ductility also reduces the risk of microcracks as well as the risk of fragile breaks.

Concrete can also be provided with an additive based on calcium nitrate (saltpeter) as a corrosion inhibitor.

For retaining walls 1 that are difficult to maintain or replace, a stainless steel concrete reinforcement will advantageously be used.

Corrosion detectors (not shown) can also be embedded in the concrete mass of the wall 1, in order to quickly detect the beginnings of corrosion of the reinforcement and to allow an intervention before the retaining wall risks s 'collapse. The detectors can be passive or active RFID detectors, that is to say with or without a battery. They can be powered by induction from an external reading device. They can include a humidity detector to detect the intrusion of water in the concrete. They can be fitted with voltage detectors and connected to the metal reinforcement of the wall, in order to detect voltage variations between two points, which can occur in the event of corrosion or reduction in the diameter of the reinforcement. They can also be based on an electrochemical measurement or a measurement of potential fields. Several detectors can be provided in the wall portion and / or in the anchoring element. The detectors advantageously allow reading from the front face 20 of the wall, which remains accessible.

The retaining wall 1 can be mounted next to other similar walls in order to retain a very long backfill. The width of each wall is advantageously between 2 and 3 meters, for optimal transport by truck. The height can be between 2.5 and 6 meters, depending on the needs.

It is important to keep the retaining walls 1 to each other in order on the one hand to ensure perfect alignment, and above all to prevent the possible collapse of a wall causing that of the adjacent walls as soon as the backfill falls through the opening thus created. The connection between adjacent retaining walls also makes it possible to retain a damaged wall by means of its valid neighbors.

In the embodiment of Figure 3, the maintenance between adjacent retaining walls is provided by a profile forming a connection of the type tenon 26 - mortise 27 on the side edge of the walls 1. A strip of foam 214 can be glued between the walls to improve waterproofing and protect the profile.

One or more metal retaining plates 213 can also be fixed to the rear face 21 of the walls 1, in order to connect two adjacent walls. The plates can be screwed into rails 212 making it possible to compensate for the variability of the clearance between two neighboring walls.

In a variant not shown, the adjacent walls are kept integral with each other by means of stainless steel cables linked to the rear face 21. Each cable can link two or more than two adjacent walls. Several cables can be provided between each pair of walls.

Figure 4 illustrates a variant in which adjacent retaining walls 1 are held by means of a sill 5A on the head of the walls, and / or one or more sills on the rear face 21.

Figure 5 illustrates an embodiment in which a drainage opening 24 is provided through the rod 30, in order to prevent the accumulation of water between the wall portion 2 and the arms 31 of the anchor element 3.

The durability of the wall also depends on the rigidity of the connection between the vertical wall portion 2 and the anchoring element 3. This rigidity is given in particular by the metal frame. For this purpose, the wall is advantageously produced in two stages.

In a first step, the anchoring element 3 is molded with the shank 30 horizontal around a frame comprising irons 70, 71 in the form of a C and in the form of an inverted C. These irons protrude at the end of the shank facing wall 2. The irons are shown in Figure 6.

In a second step, the anchoring element is mounted on the holding frame (not shown), then returned to a vertical position above a table intended to cast the wall portion 2. The frame of this wall portion is placed on the molding table. This frame advantageously comprises U-shaped and U-shaped elements 72, 73 turned upside down, oriented vertically in the normal position of the wall. These elements are inserted through the portion of reinforcement which protrudes from the anchoring element, and attached to this element. RFID sensors can be attached to the frame. Additional reinforcing elements, in bulk, can be added. The wall portion 2 is then cast around this reinforcement.

FIG. 7 illustrates a retaining wall 1 in place in front of an embankment 61, in order to protect a road 60. Tests have shown that such a wall manages to retain a load of 20 kN or greater.

Reference numbers used in figures

[0089] 1 Retaining wall 2 Wall portion facing upwards 20 Front face of the wall portion 21 Rear face of the wall portion 210 Anchor points 212 Fixing rails 213 Retaining plate 214 Foam strip 24 Drains 26 Tenon profile on the side edge of a wall 27 Mortise profile on the side edge of a wall 3 Anchoring element (or anchor) 30 Rod in a plane oriented substantially vertically 301 Lower edge of the rod 302 Upper edge shank 31 Arm of the anchor element 310 Anchor point 312 Support portion of the arms, extending under a part of the lower edge 301 313 Support surface 314 Bottom face of the support portion 315 Anchoring portion 316 First face of the anchoring portion 317 Second face of the anchoring portion 318 Upper face of the bearing portion 32 First vertical face of the rod 33 Self-adhesive sealing strips 34 Second vertical face of the verge 36 Injection pipes 5A Longr ine at the top of the wall portion 5B Stringer on the back face of the wall 6 Foundation 60 Route 61 Embankments 64 Anchor cables 65 Foot of an L-shaped wall 70.71 Horizontal C-shaped bars 72.73 Bars U-shaped vertical

Claims (18)

1. Self-supporting prefabricated reinforced concrete retaining wall (1), comprising: a wall portion (2) oriented upwards and intended to retain an embankment (61), the wall portion (2) comprising a front face (20) intended to be free and a rear face (21) against which the embankment is intended to be supported; and an anchoring element (3) projecting from said rear face and intended to anchor the retaining wall in the embankment (61), the anchoring element (3) comprising a bearing surface (313) parallel to said portion of wall (2) and intended to bear against an edge of a foundation (6). 2. Retaining wall according to claim 1, the anchoring element (3) comprising: a rod (30) in a plane oriented substantially vertically and substantially perpendicular to the wall portion (2); and at least one arm (31) extending in a plane perpendicular to the plane of the penis and oblique with respect to the wall portion (2), from the distal end of the penis (30). 3. Retaining wall according to claim 2, said at least one arm (31) being curved so as to include an anchoring portion (315) with two main faces (316, 317) inclined and a bearing portion (312). ) curved towards the wall portion (2) with two main faces (314, 318) substantially horizontal, said bearing surface (313) being formed by one of the faces of said bearing portion (312). 4. Retaining wall according to claim 3, said shank comprising an upper edge (302) and a lower edge (301), said support portion may be disposed under the lower edge (301). 5. Retaining wall according to one of claims 3 to 4, the lower face (314) of the bearing portion (312) being substantially flat and horizontal. 6. Retaining wall according to one of claims 4 to 5, the lower face (314) of the bearing portion (312) lying below the lower edge (301) of the rod (30). 7. Retaining wall according to one of claims 2 to 6, comprising a said rod (30) and two said arms (31) extending on each side of this rod (30). 8. Retaining wall according to one of claims 1 to 7, comprising at least one injection pipe (36) near the junction between said wall portion (2) and said anchoring element (3) and allowing '' inject microcement, mortar and / or resin to fill any cracks in the concrete. 9. Retaining wall according to one of claims 1 to 8, said wall portion (2) comprising two side sections facing upwards and at least one of which is provided with a profile (26; 27) allowing maintenance of tenon (26) - mortise (27) type with an adjacent retaining wall. 10. Retaining wall according to one of claims 1 to 9, said rear face (21) comprising rails (212) for fixing a retaining plate (213) with an adjacent wall. 11. Retaining wall according to one of claims 1 to 10, said rear face (21) comprising anchor points (210) for fixing retaining cables with an adjacent wall. 12. Retaining wall according to one of claims 1 to 11, said wall portion (2) comprising a metal frame with elements facing upwards in the form of a U and in the form of an inverted U, said anchoring element (3) comprising a metal frame with substantially horizontal C-shaped and inverted C-shaped elements (70, 71), the reinforcing elements in the wall portion (2) and in the anchoring element (3) being intersected. 13. Retaining wall according to one of claims 1 to 12, said anchoring element (3) comprising a drainage hole (24). 14. Retaining wall according to one of claims 1 to 12, the wall portion (2) comprising a drainage hole (24) between the front face (20) and the rear face (21). 15. Retaining wall according to one of claims 1 to 14, comprising a sill (5A) on the top of the wall or on said rear face. 16. An assembly comprising a retaining wall according to one of claims 1 to 15 and a foundation (6) on which rests said wall portion (2) and against which rests said bearing surface (313). 17. The assembly of claim 16, said foundation (6) comprising a drain. 18. Wall comprising a plurality of retaining walls according to one of claims 1 to 15, at least two adjacent walls being juxtaposed and rigidly linked together by at least one sill (5A, 5B).