EP0429379B1 - Retaining structure and method of construction of a retaining structure - Google Patents

Abstract

Building element for the construction of a retaining structure, characterised in that it comprises: . a facade panel (1) having a transverse plane of symmetry (P2) perpendicular to the direction of its face (5), . and a rib beam (7) extending in the plane of symmetry from the upstream face (3) of the panel, possessing a base (9) at least locally coplanar with that of the panel and having at least locally a height (h) generally smaller than that (H) of the panel. <IMAGE>

Description

The present invention relates to the field of support or retention of natural or artificial mass of more or less movable materials, likely to experience, by erosion, vibration, cracking, cleavage, landslides harmful to themselves or the environment.

Although many implementations can be envisaged, a preferred application of the invention relates to the support of a working face in cut or fill in relation to a site to be protected, such as a built-up area, road, railway, railway, etc. .

To solve the above problem, various technical proposals have been made based on the idea that it was advisable to erect a screen assuming a function of retention of the mass of materials behind their upstream facing.

We quickly realized that such screens had to withstand horizontal constraints from the retained land.

To meet this requirement, a proposal was made to make the screens in the form of wall-weights by analogy with the design developed for the constitution of hydraulic dams. According to such a concept, the self-weight of the wall is the only element of resistance vis-à-vis the thrust to support.

If such walls are able to meet the objective to be achieved, on the other hand, they are of a heavy and expensive execution.

It was then envisaged to involve the materials in the resistance which the screen must present to the thrust of such materials. To this end, many proposals have been made which consist in making the screen in the form of a thin veil, vertical or inclined, rising from a sole having an upstream part, called heel, buried in the material. to support. Generally, buttresses are provided on the upstream face of the web to contribute to its mechanical strength.

Such structures can be produced in a more practical and less costly manner, but do not make it possible to respond optimally to the requirements of high height support and the constitution of vegetable facings to improve the aesthetic appearance of the erected construction.

A different technique has been proposed, notably by document FR-A-2406700 for constructing retaining screens from prefabricated stackable modules. Each module comprises a front plate extended from its upstream face, by a beam-rib, extending in a plane of symmetry of the plate. Such modules make it possible to partially meet the requirement for vegetable facings, but do not allow control of the forces exerted on the prefabricated modules stacked and, therefore, a real justification for stability.

The known techniques therefore still do not make it possible to solve the problem thus posed overall, and the need is always felt to be able to have light, inexpensive and easy to implement means, to constitute a support structure which can be established on a great height, without risk of disorder or ruin over time, while presenting a facade of siding easily vegetable in a sustainable manner over time, to improve the aesthetic appearance.

• préparer le sol à partir duquel l'ouvrage doit s'ériger,
• poser sur ce sol une première rangée d'éléments disposés successivement à côté l'un de l'autre sans contact mutuel en ménageant un intervalle entre les bords latéraux et de telle manière que les plaques définissent la façade de l'ouvrage et que les poutres-nervures soient dirigées vers le massif à soutenir,
• placer, entre les bords latéraux espacés des plaques successives, des filtres appliqués et maintenus contre les faces amont des plaques de façade,
• combler les alvéoles définis par les poutres-nervures avec un matériau de remblai compacté, pour que son niveau s'établisse au moins dans le plan des bords supérieurs des plaques,
• poser sur ce niveau, et comme dit précédemment, une deuxième rangée d'éléments, en faisant en sorte qu'il n'existe pas de contact entre les plaques et poutres-nervures des éléments d'une rangée à l'autre,
• combler les alvéoles de la deuxième rangée, comme dit précédemment,
• et procéder de même, pour autant de rangées nécessaires, pour atteindre la hauteur devant être conférée à l'ouvrage.

To achieve the above objectives, the invention relates to a method of constituting a retaining structure, from construction elements of the same type, each comprising a facade plate having two edges respectively upper and lower and two lateral edges and extended from its upstream face, by a beam-rib, extending in the plane of symmetry of the plate. The process is characterized in that it consists in:

• prepare the soil from which the structure is to be erected,
• place on this floor a first row of elements arranged successively next to each other without mutual contact, leaving a gap between the lateral edges and in such a way that the plates define the facade of the structure and that the beams - ribs are directed towards the massif to be supported,
• place, between the spaced lateral edges of the successive plates, filters applied and held against the upstream faces of the facade plates,
• fill the cells defined by the beams-ribs with a compacted backfill material, so that its level is established at least in the plane of the upper edges of the plates,
• place a second row of elements on this level, and as said above, ensuring that there is no contact between the plates and beams of the elements from one row to another,
• fill the cells in the second row, as mentioned above,
• and do the same, for as many rows as necessary, to reach the height to be given to the structure.

• une première rangée de base, posée sur le sol et constituée d'éléments de construction disposés successivement l'un à côté de l'autre sans contact mutuel, en ménageant entre leurs bords latéraux des intervalles munis de filtres, de telle sorte que les plaques définissent la façade de l'ouvrage et que les poutres-nervures s'étendent en direction du massif à soutenir,
• une couche de matériau de remblai compactée, remplissant les alvéoles délimitées entre les poutres-nervures et s'établissant à un niveau au moins égal à celui des bords supérieurs des plaques de façade,
• n rangées superposées d'éléments (I) associés aux couches de remblai correspondantes et dans chacune desquelles les plaques (1) des éléments sont disposées sans contact avec soit les plaques, soit les poutres-nervures de la rangée immédiatement inférieure.

The subject of the invention is also, as a new product, a retaining structure produced from construction elements of the same type, comprising a facade plate having two edges respectively upper and lower and two lateral edges, said plate being extended, from its upstream face, by a beam-rib extending in the plane of symmetry of the plate, characterized in that it comprises:

• a first base row, placed on the ground and consisting of construction elements arranged successively one next to the other without mutual contact, providing between their lateral edges intervals provided with filters, so that the plates define the facade of the structure and that the beams-ribs extend in the direction of the solid to be supported,
• a layer of compacted backfill material, filling the cells delimited between the ribbed beams and establishing themselves at a level at least equal to that of the upper edges of the facade plates,
• n superimposed rows of elements (I) associated with the corresponding backfill layers and in each of which the plates (1) of the elements are arranged without contact with either the plates or the ribbed beams of the immediately lower row.

Various other characteristics will emerge from the description given below with reference to the appended drawings which show, by way of nonlimiting examples, embodiments and implementation of the subject of the invention.

Fig. 1 is a perspective of the building element according to the invention.

Fig. 2 is a side view corresponding to FIG. 1 .

Fig. 3 is a top view corresponding to FIG. 1 .

Fig. 4 is a schematic view showing the implementation of the method for the constitution of a retaining structure.

Fig. 5 is a front view taken along the line VV of FIG. 4 .

Fig. 6 is a schematic plan view corresponding to the line VI-VI of FIG. 5 .

Fig. 7 is a perspective similar to FIG. 1 illustrating an alternative embodiment of the building element.

Fig. 8 is a side view showing, parallel to FIG. 4 , the implementation of the element according to FIG. 7 for the construction of a retaining structure with vertical facing or at low inclination.

The building element according to Figs. 1 and 2 is formed in the form of a one-piece assembly made of any suitable material. In the preferred field of application of the object of the invention, such a construction element is produced in a prefabricated monolithic manner, in reinforced concrete according to the manufacturing techniques known to those skilled in the art.

The building element, designated as a whole by the reference I , comprises a front plate 1 which can be flat or curved, while being convex or concave. In all cases, it can be considered that the front plate 1 is defined or materialized by a general plane P.

The front plate 1 has a so-called downstream face 2, a so-called upstream face 3 , two lateral edges 4 , preferably but not necessarily parallel to each other and rising from a base 5 extending in a reference plane P₁ . The plate 1 is also defined by an upper edge 6 which is preferably but not necessarily parallel to the base 5 .

The construction element I further comprises a beam-rib 7 forming an integral part of the plate 1 extending from the upstream face 3 of the latter. The beam-rib 7 is arranged on edge to be placed in a plane P₂ of transverse symmetry of the plate 1 and of the element I , such a plane P₂ being perpendicular to the reference plane P₁ . The rib-beam 7 extends from the upstream face 3 to which it is connected, preferably, by two lateral fillets 8 . The beam-rib 7 has a base 9 which is, in the example illustrated, coplanar with the base 5 of the plate 1 . The beam-rib 7 has a height h which is generally less than the height H of the plate 1 as shown in the drawings.

Fig. 1 shows that the beam-rib 7 is delimited at its free end by a vertical face 11 which can, optionally, be provided with anchoring means 12 , as is apparent from what follows. The means 12 may consist of a heel 13 extending laterally on either side of the beam-rib 7 or also by a means 14 for anchoring or fixing a cable, rope or strip whose function can be considered analogous to the anchoring principle known in soil reinforcement techniques.

The beam-rib 7 has two lateral faces 15 which can be supported substantially at the level of the base 9 . A such shouldered conformation can result from a state of convergence of the lateral faces 15 from the base 9 or even from the presence of two flanges 16 projecting from the base 9 to be connected to the walls 15. Shoulders 17 and 18 respectively may be provided in a similar manner as regards the base 5 of the plate 2 and the base 19 of the heel 13 .

In a generally preferred embodiment, the beam-rib 7 extends perpendicular to the reference plane P₁, while the plate 1 is formed so that its overall plane P is perpendicular to the plane P₁ , as illustrated in particular in FIG. 2 . It can, however, be envisaged to produce the element I so that the plane P of the plate 1 makes an angle α different from 90 ^o relative to the reference plane P₁ . Fig. 2 shows, by way of example, an embodiment in which the plane P is inclined by a measure α opposite the beam-rib 7. An inclination of opposite direction could also be envisaged.

The lateral faces 15 of the rib-beam 7 , whether or not provided with the shoulders 16, can be smooth according to FIGS. 1 and 2 or, again, provided with local conformations 20 and 21 successively in hollow and in relief, so as to create, in the plane of each of the lateral faces, zones in which, in the event of a slip, shear occurs of site material. The example of conformation illustrated in fig. 3 is given only without implied limitation to illustrate a possible prefabrication embodiment.

It can be envisaged to give the beam-rib 7 a constant overall width from the upstream face 3 to the rear end portion or a width increasing in the same direction. This last embodiment has the advantage, in the event of a tendency to slide downstream of the element, to increase the friction by increasing the compaction by the wedge effect.

The construction element described above is used in the following manner to construct a retaining structure II in relation to a face of size 25 such as shown schematically in fig. 4 .

The ground S preceding the cutting face 25 is prepared in accordance with the usual regulations in this area in order to have a coherent base surface, defining a stable support plane. The preparation can therefore consist of a simple leveling or even the constitution of a support sole.

On the ground S, there is a first row R₁ of identical building elements I which are all arranged successively one next to the other without, however, that contact occurs between the vertical edges 4 of the plates 1 . In other words, the elements I are arranged side by side with a gap 26 between the edges 4 . The elements I of the row R₁ are arranged so that the plates 1 define the facade of the structure to be erected and so that the beams-ribs 7 extend in the direction of the block M to be supported ( fig. 5 and 6 ). The elements I can be of simple type or, on the contrary, provided with any one of the anchoring means 13 or 14 described above. In the latter case, the means 14 is then provided with a slender member intended to improve the anchoring.

When all the elements I of the row R₁ have been arranged as said above, the intervals 26 are provided, by application and holding against the upstream faces 3 , of filters 27 consisting, generally, of a strip, plate or panel of openwork material of which the mesh opening is chosen according to the granulometry of the materials of the solid mass M or of backfill materials. The application and temporary maintenance of the filters 27 can be ensured in any suitable manner chosen according to the nature of the materials present.

Another step of the process then consists in constituting a layer of backfill material m ₁ behind the various plates 1 so as to fill the successive cells which are delimited by the beams-ribs 7 . The backfill material is chosen according to the usual criteria in the matter and is compacted according to the also usual prescriptions, so as to be established at a level n ₁ passing at most in the plane from the upper edge 6 of the plates 1 , occupying a plane parallel to the reference plane P₁ .

Another step of the method then consists in establishing, by pressing on the level n ₁ , a second row R₂ of elements 1 which are arranged as said above while being placed relatively so that the plates 1 are arranged, preferably but not exclusively, in apparatus in staggered relation to those of the constituent elements of the row R₁ .

According to the method of the invention, the elements I of the row R₂ are placed on the level n ₁ , so that no contact takes place between the bases 5 and 9 of the elements of the row R₂ with the upper edges of the constituent elements I of row R₁ . Compliance with such a requirement is, for example, achieved by shifting the elements I of the row R₂ so that the plates 1 of these elements are moved upstream relative to the plates 1 of the elements I of the row R₁ .

The row R₂ is completed by the constitution of the layer of backfill material m ₂ compacted as said previously with regard to the layer m ₁ , so as to define a level of laying n ₂ .

This is followed immediately for the constitution of as many rows R₃, R₄, R n as it is necessary to superimpose so as to give, to the structure II , the retaining height desired to retain and consolidate the massif M , as illustrated in fig. 4 .

As is apparent from the examination of the drawings and the preceding description, the construction element and the implementation method according to the invention make it possible to constitute a retaining structure II from successive rows of elements of construction, juxtaposed without contact and delimiting cells filled with a compacted fill material.

Such a retaining structure II can be built on variable heights from prefabricated building elements which are, moreover, of small bulk and relatively low mass. It thus becomes possible to have advantageous construction materials that can be easily handled on site without requiring the use of heavy and bulky lifting installations.

In addition, the retaining structure II is erected from building elements which do not have contact with each other, so that a configuration easily adaptable to the local profile can be easily conferred, in particular as regards the facade of book II .

Furthermore, it should be noted that the retaining structure II does not contain any material whose long-term behavior is poorly known or is the subject of uncertainty as regards the durability of the mechanical characteristics over time.

Furthermore, the absence of contact between the construction elements, either in the same row, or between two superimposed rows, eliminates the fundamental drawbacks involved in punching in structures constructed from modular elements in permanent contact.

The construction by juxtaposition of the contactless elements I moreover gives the structure II a certain flexibility allowing it to absorb differential settlements without the appearance of disorder likely to harm its retention and support function.

Furthermore, it should be noted, in particular, by examining FIGS. 4 and 6 , that the upstream offset of the plates of each row from the bottom makes it possible to release, for each plate, a significant mass of soil from successive levels n thus offering the possibility of planting plants. Such an advantage is particularly noticeable in the case where the production of each construction element I involves the choice of a curved plate 1 , convex with regard to its downstream face II .

It should be noted that the choice of the production of the plate 1, in its form, its structure or its composition, can easily be retained to take account of absorption properties. phonic by reflection or absorption.

In the example according to fig. 4, the structure II is then completed by the addition of a mass of materials m ′ possibly not compacted, added and spread over the level n _n to perfect the massif, with a view to providing it with a particular shape and a possibility of revegetation.

Fig. 7 shows an alternative embodiment in which the beam-rib 7 is produced so as to have, in its part close to the plate 1 , a base 9₁ coplanar with the base 5 of the plate 1 and, beyond this part, a base 9₂ extending beyond the reference plane P₁ . Such an embodiment allows, as illustrated in FIG. 8, to have, between the base 5 of the plate 1 and the base 9₂ , a clearance 30 allowing the elements of the successive rows to be placed in exact superposition as illustrated in FIG. 8 , while respecting the requirement of no point or total contact between the construction elements of two superimposed rows. Such an embodiment makes it possible to erect a structure II , the facade of which consists of plates 1 having no relative offset between them between them.

The invention is not limited to the examples described and shown, since various modifications can be made thereto without departing from its scope as defined by the appended claims.

Claims (12)

1. A method of making a supporting structure from structural members (I) of the same type, comprising a frontage plate (1) which includes two edges, respectively upper and lower, and two side edges (4) and which is extended from its uphill surface (3) by a reinforcement beam (7) extending in the plane of symmetry of the plate,
      characterised in that it comprises:

   - preparing the ground (S) on which the structure is to be erected,

   - positioning on the ground a first row (R₁) of members arranged successively side by side without mutual contact, by forming a gap (26) between the side edges (4) and in such a way that the plates define the frontage of the structure and the reinforcement beams are directed towards the body to be supported,

   - placing between the spaced side edges of the successive plates, filters (27) which are applied to and held against the uphill surfaces (3) of the frontage plates,

   - filling the cells defined by the reinforcement beams with a compacted embankment material (m₁), so that its level (n₁) is established at least in the plane of the upper edges of the plates,

   - positioning a second row of members (R₂) on said level as previously stated, ensuring that there is no contact between the plates and reinforcement beams of the members from one row to another,

   - filling the cells of the second row as previously stated, and

   - proceeding in the same way for as many rows as are necessary to reach the height which the structure (II) is to be given.
2. A method according to claim 1, characterised in that, to ensure that there is no contact between the plates and reinforcement beams of the members from one row to another, it comprises positioning the structural members in such a way that the plates are offset from one row to another in an uphill direction from the base of the structure.
3. A method according to claim 1, characterised in that, to ensure that there is no contact between the plates and reinforcement beams of the members from one row to another, it comprises superposing the structural members, which are arranged so that each has a clearance (30) provided between the base (5) of the plate (1) and the base (9₂) of the reinforcement beam.
4. A supporting structure made from structural members (I) of the same type, comprising a frontage plate (1) which includes two edges, respectively upper and lower, and two side edges, said plate being extended from its uphill surface (3) by a reinforcement beam (7) extending in the plane of symmetry of the plate, characterised in that it comprises:

   - a first, base row (R₁) positioned on the ground and comprising structural members (I) arranged successively side by side without mutual contact by having gaps (26) provided with filters (27) between their side edges (4), in such a way that the plates (1) define the frontage of the structure and that the reinforcement beams (7) are directed towards the body (M) to be supported,

   - a compacted layer (m₁) of embankment material, filling the cells demarcated between the reinforcement beams and being established at a level (n₁) at least equal to that of the upper edges of the frontage plates,

   - n superposed rows of members (I) associated with the corresponding embankment layers, in each of which rows the plates (1) of the members are arranged without any contact with either the plates or the reinforcement beams of the row immediately below.
5. A supporting structure according to claim 4, characterised in that the members (I) are arranged so that the plates (1) are offset from one row to another in an uphill direction from the base.
6. A supporting structure according to claim 4, characterised in that the members (I) are arranged so that the plates (1) are superposed, the members (I) each having a clearance (30) between the base (5) of the plate (1) and the base (9₂) of the reinforcement beam such that there is no contact between the plates and reinforcement beams of the members from one row to another.
7. A supporting structure according to claim 4, characterised in that the members (I) each have a reinforcement beam (7), the width of which increases from the uphill surface of the frontage plate (1) towards the rear part.
8. A supporting structure according to claim 4, characterised in that the members (I) each have a frontage plate of which the downhill surface (2), defined by a plane (P), forms an angle (α) other than an angle of 90° with a plane perpendicular to the plane passing through the base.
9. A supporting structure according to claim 4, characterised in that the members (I) each have a reinforcement beam (7) provided on its two side surfaces (15) with local conformations (20, 21) which are successively protruding and recessed.
10. A supporting structure according to claim 4 or 9, characterised in that the members (I) each comprise a reinforcement beam (7) which has anchoring means (12) at its end opposite the plate (1).
11. A supporting structure according to claim 4 or 8, characterised in that the members (I) each comprise a frontage plate (1) connected to the reinforcement beam (7) by fillets (8).
12. A supporting structure according to any of claims 1, 4 or 7, characterised in that the members (I) each comprise a frontage plate (1) and a reinforcement beam (7) which has a shouldered base (16, 17).

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