FR2767847A1 - Retaining wall for waste collection site - Google Patents

Abstract

The wall is made up of panels (13, 15) joined together so that they apply alternate traction and compression forces. The lower edges of the panels are connected to the edges (19) of slabs (7) forming platforms for bins of separated waste. The prefabricated wall panels are erected on concrete foundations (25) and joined together by their reinforcing members, after which concrete is cast in the gaps between them to make a continuous wall. The slabs are then cast in situ, forming a lower level for the separate waste bins, e.g. for glass, plastics, cardboard, scrap iron and garden waste, while the upper level above the wall, which is back-filled with rubble, can be used by light vehicles and trailers dumping waste.

Description

 Retaining wall, in particular for recycling center, and method of constructing such a wall.

 The field of the invention is that of civil engineering. More specifically, the invention relates to a retaining wall, in particular for recycling centers, and to its construction method.

 Such retaining walls are intended to separate two areas placed at two different altitudes, one being for example at ground level and the other about 2 m to 2.50 m higher. The lower area is intended to receive different containers allowing the sorting of waste according to their nature (glass, plastic, cardboard, scrap, garden waste, etc.). These containers are moved using trucks.

 The lower area must therefore be wide enough to allow an easy approach of these trucks which generally maneuver in reverse to hang the containers. This area must also support the weight of the trucks. The upper area is a parking area for light cars, possibly towing a trailer, but never generally exceeding 3.5 tonnes laden. The driver of the car transporting the waste parks near the chosen container and unloads the waste by throwing it in the container below.

To facilitate the parking of light cars and the movement of trucks,
The organization of the recycling center follows a so-called "spike" (or "sloping") layout, in which the successive sections of the retaining wall are arranged at right angles, in order to create boxes for receiving the containers, as shown in Figure 1 attached.

 More generally, the invention also relates to any retaining wall intended to contain an embankment and having a spike shape. One can for example use such a wall for the realization of a parking lot on which cars are parked on the cob, this parking lot being located below a layer of earth which must be contained, in order to prevent it from becoming pours into the parking lot.

 Retaining walls are already known, illustrated for example by patent document FR 2 702 502. According to this document, a retaining wall made of prefabricated elements, intended for recycling centers, is made up, alternately, of a flat panel and on the other hand at least a portion of the wall working as a console, as is always the case.

 Each portion of the wall working in a console has an L shape and is made up of a vertical veil and a sole. The purpose of the sole is to compensate for the moment of overturning of said portion of wall, this moment being due to the thrust of the earth being contained by this wall.

 This type of construction has many drawbacks. First of all, it is necessary to use a large amount of concrete and therefore reinforcement for the realization of the sole of the part, which works in console.

 Furthermore, the moment of the wall overturning induces very strong pressures of the sole on the ground, which means that this sole has to be founded on resistant soil which is sometimes found only at relatively great depths. Consequently, it is necessary to carry out an expensive earthwork.

 Finally, each portion of L-shaped wall is not easy to transport and move because of its heavy weight and its shape which occupies a lot of space in a truck tipper and prevents any overlapping of two pieces.

 The invention particularly aims to overcome these various drawbacks of known techniques.

 More specifically, an objective of the invention is to provide a retaining wall, and a corresponding construction method, which is more economical than known techniques, for at least equivalent strength and reliability.

 Thus, the object of the invention is in particular to provide such a wall, which does not require significant earthworks, up to deep resistant soils.

 Another objective of the invention is to provide such a wall, the constituent elements of which require less material (concrete and reinforcement). The invention also aims to provide a rapid, simple and inexpensive construction process, requiring less raw materials than known techniques.

 The invention also aims to provide such a wall, the elements of which are easy to transport and compact.

These objectives are achieved by means of a retaining wall formed by a series of wall sections defining a spike profile, said wall sections being assembled so as to alternately form inward right angles and outgoing right angles, each of said wall sections, with the exception of the end wall sections, being maintained:
- on the one hand at the foot of the wall;
- and on the other hand at the head of the wall, by joining each of its sections of
neighboring wall, one of said neighboring wall sections exerting a force of
traction, and the other of said neighboring sections of wall exerting a force of
compression.

 In other words, the invention is based on a completely new, and not obvious, approach to the construction of a retaining wall. Instead of making the sections of the wall work in a console, by providing a sole to avoid any overturning, the invention proposes to create load transfers on sails which are an extension of the efforts. The wall by itself resists pushing (due to the earth and overloads) thanks to the stiffness of the bottom of the wall and the top of the wall.

 The charges being thus transmitted, it is then possible to take them back at the foot of the wall.

 Advantageously, the support at the foot of the wall is ensured by a spade of paving and / or by friction on a shaped bottom.

 Preferably, each of said wall sections comprises a substantially horizontal upper beam and provided with means for hooking to a similar beam of a neighboring wall section.

 Thus, at one of its ends, the beam abuts on the perpendicular wall. At the other end, the wall retains, "by pulling", the beam. Each section of wall therefore has a beam which requests a perpendicular wall. The beams of the end spans can be taken up by a final transition wall.

 Thanks to these features of the invention, the sole of the prior art can be omitted. As a result, the quantity of concrete used to manufacture the panels is reduced by 40% and the quantity of reinforcing steel by 50%.

 In addition, the necessary earthworks are greatly reduced, especially in the case of deep resistant soils.

 Advantageously, said attachment means comprise means for keying in the metal reinforcements of said upper beams.

 Preferably, concrete is poured between two neighboring sections of wall.

 According to an advantageous embodiment of the invention, the upper part of at least some of said wall sections is extended by a stop forming a wheel guard.

 According to a particular application of the invention, the wall is installed in a recycling center, the platform then constitutes a parking area for vehicles coming to unload waste and the spikes are intended to receive containers for storing said waste. In addition, the upper beam of each support panel constitutes a stop for the wheels of vehicles coming to unload waste, so as to prevent it from falling into the herringbone boxes.

 The invention also relates to prefabricated wall sections, in themselves, intended to be used for the production of a retaining wall as described above.

The invention also relates to a method of constructing the wall according to the invention comprising the following steps:
- installation of wall sections defining a herringbone profile, said wall sections being
assembled so as to form alternating right angles and
outgoing right angles;
- assembly of the high beams fitted to each of said sections of wall, in
outgoing angles, then in re-entering angles;
- pouring of a spade of paving.

More specifically, this method can include the steps belonging to the group comprising the following steps:
- pouring a level clean concrete,
- laying of at least two retaining sections and securing these
last provisionally,
- keying, at the angle exiting between two neighboring sides, of these
two sides over their entire height, and their two respective beams,
- keying, at the angle returning between two neighboring sections, of their
two respective beams,
- pouring of paving spades,
- pouring of a slab at the base of said retaining sections,
- placement and compaction of backfill behind the retaining sections.

 This process is simple and quick to implement. The various operations, such as pouring concrete on site, are reduced.

 Consequently, this wall and its construction method make it possible to reduce construction costs. This advantage is particularly advantageous at present for the local communities which have the obligation to equip themselves with recycling centers to respect the European standards.

 The invention will be better understood on reading the following description of an embodiment of the invention, given by way of illustrative and nonlimiting example, this description being made with reference to the accompanying drawings in which: Figure 1 is a diagram representing the retaining wall according to the invention, installed in a recycling center, - Figure 2 is a schematic section illustrating the forces exerted on the retaining wall according to the invention, - Figure 3 is a top view of the retaining wall according to the invention, - Figure 4 is a sectional plan view of the retaining wall according to the invention, - Figures SA and 5B illustrate the principle of keying the wall sections according to the invention , respectively for the outgoing and returning angles, - Figure 6 is a flowchart representing the different stages of the manufacturing process of said wall according to the invention, and - Figure 7 illustrates another mode of implantation of a thimble chetterie, top view, also compatible with the technique of the invention.

 FIG. 1 shows a retaining wall installed in a recycling center.

This wall is intended to contain an embankment 1 constituting a platform 3, located at an altitude above ground level 5. The passenger cars in which the users of the recycling center transport their waste are parked on said platform 3.

 The wall consists of successive retaining panels (or sections of wall) arranged perpendicular to each other, so as to form boxes "spike" 7, intended to receive dumpsters. The wall therefore has a succession of inward angles 9 and outgoing angles 11 and longitudinal 13 and transverse support panels 15.

 When the invention is used in a recycling center, the longitudinal panel 13 has for example a length of 5 to 6 meters and the transverse panel 15, a length of approximately 3 meters. However, in another alternative embodiment, the panels 13 and 15 could be of identical length.

 FIG. 2 illustrates the forces exerted on a support panel 13 (they are identical for the panel 15), by the embankment 1. More precisely, the arrow R indicates the result of the thrust forces exerted on the panel 13. This result is breaks down into a horizontal component RH and a vertical component RV compensated by the ground 5.

In the prior art described in document FR 2 702 502, the horizontal component RH is compensated for by the sole forming an inseparable assembly with the vertical wall veil and exerting a restoring force. The invention consisted in eliminating this sole and in considering a different structure of the wall to compensate for the horizontal RH and vertical RV components. As illustrated in Figure 2, the component
RH is broken down into an RHl component acting on the upper part of the panel 13 and an RH2 component acting on the lower part of it.

 According to the invention, the action of the RH2 component is compensated for by the presence of a concrete slab 17. This slab 17 itself resists the thrust of RH2 by friction on the ground 5 and thanks to the presence of a slab spade 19 provided at the periphery of said slab 17. Furthermore, as the various successive panels are assembled the to each other, the upper part of the panel undergoing the RHl component urges the two adjacent perpendicular panels, one in tension, the other in compression (see the respective arrows T and C in FIG. 3). The panels 13, 15 being also linked to the slab 17, cannot be lifted, because the weight of the slab counteracts this action.

 According to an advantageous alternative embodiment of the invention, as illustrated in FIG. 2, each support panel 13, 15 has in its upper part a beam 21 forming a substantially horizontal return towards the embankment 1. Each beam 21 of a retaining panel 13,15 is linked to the beam of the next panel 15, 13 and also exerts a tensile force and a compressive force respectively on the two adjacent beams.

 This beam 21 advantageously also serves as a wheel stop to prevent passenger cars parked on the platform 3 from tipping over in a box 7 or in a bucket.

 The assembly of two successive support panels 13, 15 will now be described with reference to FIG. 3.

 In an outgoing angle 11, the assembly is carried out by keying over the entire height of the panels 13, 15, by means of a rod introduced vertically into the steel frames protruding from said panels and over the height of the beams 21 of the same way. In a re-entrant angle 9, the panels 13, 15 are simply fitted one inside the other over their entire height, because the forces exerted by the embankment 1 tend to bring the two panels closer together. The upper beams 21 are assembled by keying as described for the outgoing angle. In addition, in the two aforementioned cases, concrete 23 is poured over the entire height between two neighboring panels to form the angle.

More precisely, the keying is carried out as follows:
- outgoing angle (figure SA):
- on the height of panels P1 and P2 via steels
waiting beyond the panels (triangle abc);
- on the height of the flat beams by means of steels
waiting beyond the beams (square cdef);
- re-entrant angle (Figure 5B):
- on the height of the flat beams by means of steels
waiting beyond the beams (ghij square).

 The invention also relates to the method of construction of this retaining wall which will now be described with reference to Figures 1, 4 and 6.

 Preliminary work is carried out by an earthmoving company in order to establish a platform with the necessary and sufficient bearing qualities for the seating of panels 13, 15 and slab 17. These criteria must be met for the passage trucks collecting containers. The floor must have a Westergaard lift coefficient greater than or equal to 60 M.Pa/m. This work was already carried out in the prior art and the invention therefore does not require additional work.

The process then includes the following steps:
- Pouring of cleanliness concrete 25 level, in order to be able to adjust the retaining panels 13, 15;
- Installation of support panels 13, 15, checking the squareness and the plumb of these;
- Temporary joining of the panels using a holding bar 27 in order to prevent their fall;
- Assembly by keying of the panels 13, 15 in the outgoing angle 11, over the entire height of the panels and the beams 21 and pouring of the concrete 23;
- assembly by keying of the panels in the re-entrant angle 9, at the level of the beams 21 and pouring of the concrete 23;
- shoring of the panels, in particular the longitudinal panels 13;
- pouring of the spades 19 of the slab then of the slab 17 by taking up the waiting frames at the bottom of the support panels, as illustrated in FIG. 4;
- keying of high beams;
- Laying of a drainage pipe 29 behind the panels 13, 15 and a drainage fabric covering it to protect it from the fill in the fill;
- backfilling behind the panels 13, 15 as an "all-round" backfill and compaction thereof, without thereby requesting said panels;
- Installation of a termination panel 31 at each end of the assembly of several successive support panels.

 Although the present description presents the construction of a recycling center, it is clear that the retaining wall can be applied in any other field where such a wall may be necessary (parking lots, gardens, etc.).

 Furthermore, other locations, such as that illustrated in FIG. 7, can be used. In the case of this figure 7, the wall 71 should be considered as an end wall.

Claims (10)

 compression (C).  traction (T), and the other (13) of said neighboring sections of wall exerting a force  neighboring wall, one (15) of said neighboring wall sections exerting a force of  - and on the other hand at the head of the wall, by joining each of its sections of  - on the one hand at the foot of the wall;  CLAIMS 1. Retaining wall formed by a series of wall sections (13,15) defining a spike profile, said wall sections (13,15) being assembled so as to alternately form re-entrant right angles (9) and outgoing right angles (11), characterized in that each of said wall sections (13,15), with the exception of the end wall sections (31), is maintained: 2. Retaining wall according to claim 1, characterized in that the maintenance at the foot of the wall is ensured by a spade (19) of paving and / or by friction on a shaped bottom. 3. Retaining wall according to any one of claims 1 and 2, characterized in that each of said wall sections (13,15) comprises a substantially horizontal upper beam (21) and provided with attachment means to a similar beam of a neighboring wall. 4. Retaining wall according to claim 3, characterized in that said attachment means comprise means for keying the metal frames of said upper beams (21). 5. Retaining wall according to any one of claims 1 to 4, characterized in that a concrete pour (23) is provided between two adjacent sections of wall. 6. Retaining wall according to any one of claims 1 to 5, characterized in that the upper part of at least some of said wall sections (13,15) is extended by a stop forming wheel guard. 7. Pan of prefabricated wall of a retaining wall according to any one of claims 1 to 6. 8. Application of a retaining wall according to any one of claims 1 to 6 to the realization of a recycling center. 9. A method of constructing a retaining wall, characterized in that it comprises the following stages:  - laying of wall sections defining a spike profile, said wall sections (13,  15) being assembled so as to form alternating right angles  re-entrant (9) and outgoing right angles (11)  - assembly of high beams (21) fitted to each of said wall sections,  in the outgoing angles (11), then in the inward angles (9);  - pouring of a spade (19) of paving. 10. A method of constructing a retaining wall according to claim 9, characterized in that it comprises the steps belonging to the group comprising the following steps:  - pouring concrete (25) of level cleanliness,  - installation of at least two retaining sections (13, 15) and securing of  these temporarily,  - keying, at the outgoing angle (11) between two neighboring faces, of these  two sides over their entire height, and their two respective beams (21),  - keying, at the re-entrant angle (9) between two neighboring sides, of  their two respective beams (21),  - pouring spades of paving (19),  - pouring of a slab (17) at the base of said retaining sections (13, 15),  - placement and compaction of backfill (1) behind the sides of  support (13, 15).