FR3107287A1 - Method of supporting at least one wall of a land - Google Patents

Abstract

The invention relates to a method for supporting at least one wall, called a working face, of a site for the construction of a building infrastructure, said working face having at least one main surface extending substantially. vertically, in which: - at least one panel (1, 1 ', 21, 22, 23) is placed in contact with said working face (4), characterized in that the following steps are carried out: - prior to the establishment of each panel (1, 1 ', 21, 22, 23), there is at least one element, said element (6, 7, 30, 31) buttress, adapted to be able to present a compressive strength according to a direction orthogonal to the plane in which the said panel extends, the said buttress element extending at least partly in a direction orthogonal to the plane in which the said panel extends, - after having put in place the said buttress element (6, 7 , 30, 31), a jacking gantry (3) adapted to be able to move vertically ch aque panel (1, 1 ', 21, 22, 23) so as to put it in place in contact with said working face, - after having put in place said driving gantry (3), said panel is placed in contact with said face in size, said panel (1, 1 ', 21, 22, 23) being arranged so as to present at least one main face bearing against said abutment element (6, 7, 30, 31). Figure for the abstract: Fig. 1

Description

Method of supporting at least one wall of a ground

The invention relates to a method for supporting at least one wall, called a working face, of land, in particular for the construction of an infrastructure of a civil engineering work such as a building. Such a working face results in particular from the digging of an excavation in land intended to receive such a civil engineering work.

State of the art

There are currently several modes of earth retaining walls such as Berliner, Parisian, Lutecian or molded reinforced concrete walls for the most common. They can be of the self-stabilizing type, comprising tie rods or struts in order to be able to neutralize the thrust forces from the working face. Their implementation presents the risk of a decompression of the supported earth which can cause disorders on the adjoining structures.

The invention aims to overcome all of these drawbacks.

The aim of the invention is to propose a method for supporting a working face of a piece of land which makes it possible to simplify the installation of the panels in the ground without reducing the reliability and safety of the work.

The invention also aims to propose such a device making it possible to set up panels in the ground in conjunction with the progress of the earthworks.

Throughout the text, the terms "earthwork" or "terracing" usually refer to the operation by which the earth or materials present in a piece of land are excavated or moved in such a way as to modify the initial shape of the ground.

The excavation resulting from the establishment of the base of a civil engineering work can be either in disbursement comprising a single working face, or in collection with the creation of several working faces which are generally set up opposite. .

The invention relates to a method for supporting at least one wall, called a working face, of land for the construction of an infrastructure - in particular foundations - of a civil engineering work, said working face having at least least one major surface extending substantially vertically, wherein:
- at least one panel is placed in contact with said working face,
characterized in that the following steps are carried out:
- prior to the installation of each panel, at least one element, called abutting element, is arranged to be able to present a resistance to compression in a direction orthogonal to the plane in which said panel extends, said abutting element extending at least partly in a direction orthogonal to the plane in which said panel extends,
- after having put in place said buttressing element, a sinking gantry is put in place adapted to be able to move each panel vertically so as to put it in place in contact with said working face,
- After having set up said sinking gantry, said panel is placed in contact with said working face, said panel being arranged so as to present at least one main face resting against said buttressing element.

Each buttressing element is therefore adapted to be able to develop a reaction in a direction allowing it to neutralize the thrusts of the earth acting against said panel. According to certain embodiments, at least one buttressing element is adapted to be able to develop a reaction in longitudinal bending. In these embodiments, at least one buttressing element is suitable for supporting vertical stresses generated by the structure.

According to certain embodiments, a buttressing element is put in place comprising:
- at least one beam, called strut, extending in a main direction substantially orthogonal to the plane in which said panel extends,
- At least one beam, called a stringer, extending in a direction substantially parallel to the plane in which said panel extends and substantially orthogonal to the main direction of said strut, each stringer being fixed to a strut.

Each strut is in particular adapted to work in compression (in particular because it undergoes the forces of the working face substantially directed in a direction normal to said main surface of said working face) and in bending. Each girder is particularly suitable for working in bending.

In certain embodiments, a buttressing element is put in place, further comprising at least one post extending vertically, substantially parallel to, at a distance from and facing said working face. Each post extending vertically makes it possible in particular to constitute a support for taking up the vertical loads supported by said girders and said struts.

Nothing prevents that, in certain embodiments, at least one vertical post is a metal post having an H-shaped cross-section adapted to cooperate and hold at least one panel. In these embodiments, each H-shaped post makes it possible to constitute a support for taking up the vertical loads supported by said girders and said struts. Nothing prevents that, in certain embodiments, at least one vertical post is a metal post having a substantially circular cross section.

In some embodiments, there is nothing to prevent at least one buttressing element from comprising a metal profile forming an easel, held in an oblique position, one of the longitudinal ends of the metal profile cooperating with the metal post, the other of the longitudinal ends of the metal profile being embedded in a layer of resistant soil.

In certain embodiments, a counterbutting element is placed between two face faces facing each other, at least one strut of said counterbutting element extending between said face faces.

In some embodiments, a connector sheath is put in place so as to connect at least two struts together. In these embodiments, this connector sleeve is put in place so as to establish a connection between at least two struts, so as to allow said at least two struts to rest on the post and/or so as to allow the lateral fixing of said at least two studs on an intermediate post. Such a configuration can in particular be advantageous depending on the distance separating the facing faces.

In some embodiments, a buttressing element is put in place comprising a holding member, called a bar, extending vertically and in a secondary direction substantially orthogonal to the plane in which said panel extends so as to present at least one surface support substantially parallel to the plane in which said panel extends. In these embodiments, said bar is adapted to be able to be driven into the ground and hold said panel in place. In these embodiments, said bar is made of concrete.

In certain embodiments, when said panel is placed in contact with said working face, a viscous grout, in particular a thixotropic grout, is simultaneously injected between each panel and said working face.

The invention also relates to a method for supporting a wall characterized, in combination or not, by all or some of the characteristics mentioned above or below. Regardless of the formal presentation given, unless expressly indicated otherwise, the various characteristics mentioned above or below should not be considered as closely or inextricably linked to each other, the invention possibly relating to only one of them. these structural or functional characteristics, or only part of these structural or functional characteristics, or only part of one of these structural or functional characteristics, or any grouping, combination or juxtaposition of all or part of these structural or functional characteristics .

Brief description of figures

Other aims, characteristics and advantages of the invention will appear on reading the following detailed description of certain possible embodiments, given without limitation and which refers to the appended figures in which:

shows a sectional view along a substantially vertical plane of a support device used in a method according to a first variant embodiment of the invention;

shows a sectional view along a substantially horizontal plane of a support device used in a method according to a first variant embodiment of the invention;

shows a sectional view along a substantially vertical plane of a support device used in a method according to a second variant embodiment of the invention;

shows a sectional view along a substantially horizontal plane of a support device used in a method according to a second variant embodiment of the invention;

shows a view in section along a substantially horizontal plane of a bar of a support device used in a method according to a second variant embodiment of the invention;

shows a sectional view along a substantially vertical plane of a detail of a support device used in a method according to the invention.

Description of certain embodiments

In the illustrative figures of the invention, given solely by way of non-limiting, the proportions are not necessarily respected, and this solely for the purposes of clarity of the presentation.

In the case of a collection (figures 1 and 2) comprising at least two working faces facing each other, the buttressing element consists of a system of beams structuring the buried work. Such a beam system can be produced and installed simultaneously with the earthworks on the ground.

Figure 1, which is in the case of an excavation in collection, represents:
- on the one hand, the panel 1 during descent with sliding along the face of the excavation 4 and against the post 5 which is founded in the soil layer 18 resistant. The sinking gantry 3 is fixed on an element 6 of the beam constituting the structure,
– and, on the other hand, the panel 1 located in its final position, held at the head by the buttressing element 6 which rests on the posts 5 and which can be held at the feet depending on the height of the working face, either by an element buttressing or by an intermediate level of buttressed support combined at the base with a complementary buttressing element 19 belonging to a reinforced slab constituting the structure of the structure.

In the embodiment shown in Figures 1 and 2, the buttressing element comprises on the one hand, struts 6, 7 each extending in a main direction substantially orthogonal to a plane in which extends a panel 1, 1 ', and, on the other hand, girders 10, 11 each extending in a direction substantially parallel to a plane in which extends a panel 1, 1' and substantially orthogonal to the main direction of a strut 6, 7, each tie bar 10, 11 being fixed to a strut 6, 7.

The struts 6, 7 and the girders 10, 11 are part of a beam making it possible to neutralize the thrust forces of the ground against the panels 1, 1'.

FIG. 2 illustrates the pushing forces of the ground against the panels 1, 1' and in reaction the bearing forces mobilized by the struts 6, 7 belonging to the beam of a support device used in a method according to the invention .

The steps implemented in a method according to the invention as illustrated in Figures 1 and 2 are as follows:
- the struts 6, 7 and the girders 10, 11 are placed on the ground, then
- the gantry 3 for sinking the panels 1, 1' is put in place, then
- there is a panel 1, 1 'in contact with the face 4 of size, each panel being arranged so as to present at least one main face bearing against at least one of the buttressing elements among the struts 6, 7 and the girders 10, 11.

As can be seen in the various figures, each panel 1, 1' preferably has a tapered end 2, 2' making it easier to drive it into the ground using the gantry 3.

The gantry 3 comprises a metal beam covering the top end of the prefabricated panel 1 on which bears on each side, a sheave with its toothed pulley 53 carried by a connecting shaft 52. The metal beam also carries at each end at least one shoe 54 sliding along the body of the cylinder 50 in order to guide the panel. Each jack 50 pulls on a chain 57 driving the toothed pulley 53. Such a gantry has the following advantages: the thrust forces are centered on the panel, the thrust power of the cylinders is multiplied by two, the winding of each chain controlled by a connecting shaft ensures that the panel descends perfectly centered substantially vertically and the supporting reaction of the gantry is taken up by the integral elements of the foundation piles.

In the case of a disbursement (FIGS. 3 to 5) comprising a single working face or a working face without an opposite working face, the buttressing element preferably consists of a bar 30, 31 of concrete armed sealed in the resistant soil layer in order to support prefabricated panels 21, 22, 23 stressed by the thrust of the earth.

Figure 3 which is in the case of an excavation in disbursement, represents the prefabricated panel 21 pushed by the sinking gantry 3 and sliding along the bar 30, 31 counterbutting the support with its ends resting on at least one shoulder (or rebate) 36, 37 of a bar 30, 31 which is put in place before the start of the earthworks.

FIG. 4 shows the system for absorbing the thrust forces of a terrain 40 (illustrated by an arrow 26 going from left to right in FIG. 4) against the panels 21, each bar 30, 31 counteracting the support by reactions of support directed in the opposite direction of the arrow 26 and in the same direction.

Each bar extends in a main longitudinal direction representing its length (visible in FIG. 3) and of which at least one end is intended to be sealed in the ground, the bar extending longitudinally substantially vertically when it is in place. Each bar 30, 31 also extends at least in part in a direction orthogonal to the plane in which each panel 21, 22, 23 extends. In the embodiment represented in FIGS. 3 to 5, each bar 30, 31 has a T-shaped cross section as can be seen in Figures 4 and 5. Each bar 30, 31 thus has a base 35 and a tab 34 whose width is less than the width of the base 35 in order to provide the shoulders 36 , 37. In the embodiment shown in Figures 3 to 5, each bar 30, 31 has a cross section which does not vary along the longitudinal direction of each bar. However, it is also possible to provide for the shape of the cross section and/or the cross dimensions of each bar to vary. Each bar can for example have a length of between 1.5 m and 2.0 m, for example of the order of 2 m, the distance between the end of the tongue 34 and the end of the base 35 possibly be between 0.5 m and 1.0 m, for example of the order of 0.75 m.

Each bar 30, 31 can be sealed in the layer of resistant soil using a concrete base (not shown) cast in place.

The stability of each bar 30, 31 which can be the subject of a calculation note for its dimensioning, can be ensured for example by such a concrete base, in particular reinforced concrete, and/or, depending on the direction and the intensity of the forces coming from the ground, by one or more tie rods drilled from longitudinal sleeves integrated into the material forming each bar 30, 31.

Figure 5 shows in particular the bearing faces of the bearing shoulders of the bar 30, 31 which receive the ends of the panels 1.

There is nothing to prevent the use, as a buttressing element, of an easel made up of metal sections stuck in the layer of resistant ground to constitute a support piece capable of receiving the thrust of the panels guided by the wings of the metal sections. extending into a position close to verticality.

On the other hand, whether it is a collection or collection configuration, in the case of a working face made up of very frictional materials, such as very compact sands, it is advantageous to reduce the forces required to drive in each panel 1, 1', 21, 22, 23 by injecting a viscous grout between the inside face of each panel and the working face of the ground in place. This improves the sliding of each panel against the working face by injecting a film of viscous grout between these two elements.

Figure 6 illustrates a holding device in the earth mass during the installation of the prefabricated panel 1 making it possible to illustrate the tapered end 2, 2' of the panels 1, 1', 21, 22, 23.

It is particularly advantageous to provide that each prefabricated panel 1, 1', 21, 22, 23 ends at its base with such a pointed end, in particular bearing on its side face of the earth mass a steel blade of section 42 inclined relative to the vertical by a predetermined angle. In addition, the excavation of a leading edge below each panel can be carried out at a predetermined distance relative to the upper end of the cutting blade 42, this upper part of the cutting blade 42 being able to spare a space left free between the panel and the working face, a sliding film being able to be formed in this space by injecting a viscous grout - in particular a thixotropic grout - flowing through a pipe 48.

To obtain a good regularity of the working face 4, a carrying arm 45 of an excavator is equipped with a bucket 44 carrying a hydraulic cutter 43 whose position is adjusted by a cylinder 46.

To respect a predetermined distance between the upper end of the cutting blade 42 and the hydraulic milling cutter 43, it is possible to use a guidance system consisting of a generator 49 of laser beams fixed on the outer face of a panel to create a scan of rays in a plane parallel to the panel pointed at a mark 47 carried by the bucket 44.

The invention may be subject to numerous variants and applications other than those described above. In particular, it goes without saying that, unless otherwise indicated, the various structural and functional characteristics of each of the embodiments described above should not be considered as combined and/or closely and/or inextricably linked to each other, but to the opposite as mere juxtapositions. In addition, the structural and/or functional characteristics of the different embodiments described above may be the subject, in whole or in part, of any different juxtaposition or any different combination.

In particular, this description is given by way of illustrative example only. A person skilled in the art may make numerous modifications thereto, in addition to the variants mentioned during the description above, without departing from the scope of the invention.

Claims (8)

Method for supporting at least one wall, called a working face, of land for the construction of an infrastructure of a civil engineering work, said working face having at least one main surface extending substantially vertically, in which:
- at least one panel (1, 1', 21, 22, 23) is placed in contact with said working face (4),
characterized in that the following steps are carried out:
- prior to the positioning of each panel (1, 1', 21, 22, 23), at least one element, called counter-butting element (6, 7, 30, 31) is placed, adapted to be able to present resistance to the compression in a direction orthogonal to the plane in which said panel extends, said buttressing element extending at least partly in a direction orthogonal to the plane in which said panel extends,
- after having put in place said buttressing element (6, 7, 30, 31), a sinking gantry (3) adapted to be able to vertically move each panel (1, 1', 21, 22, 23) of so as to place it in contact with said working face,
- after having put in place said sinking gantry (3), said panel is placed in contact with said working face, said panel (1, 1', 21, 22, 23) being arranged so as to present at least one main face bearing against said buttressing element (6, 7, 30, 31). Method according to Claim 1, in which at least one buttressing element (6, 7, 30, 31) is adapted to be able to develop a reaction in longitudinal bending. Method according to one of Claims 1 or 2, in which a buttressing element is put in place comprising:
- at least one beam, called strut (6, 7), extending in a main direction substantially orthogonal to the plane in which said panel extends,
- at least one beam, called a girder (10, 11), extending in a direction substantially parallel to the plane in which said panel extends and substantially orthogonal to the main direction of said strut (6, 7), each girder being fixed to a button. Method according to claim 3, in which a buttressing element is put in place, further comprising at least one post (13, 14, 15, 16) extending vertically, substantially parallel to, at a distance from and facing said working face (4 ). Method according to one of Claims 3 or 4, in which a counterbutting element is placed between two facing face faces, at least one strut of said counterbutting element extending between said face faces. Method (1) according to one of Claims 3 to 5, in which a connector sheath is put in place so as to connect at least two struts together. Method (1) according to one of Claims 1 to 6, in which a buttressing element is put in place comprising a holding member, called a strip (30, 31), extending vertically and in a secondary direction substantially orthogonal to the plane in which said panel (21, 22, 23) extends so as to present at least one support surface substantially parallel to the plane in which said panel extends. Process according to one of Claims 1 to 7, in which, when the said panel is placed in contact with the said working face, a viscous grout is simultaneously injected between each panel and the said working face.