EP0166656A2 - Prefabricated retaining elements for protecting, reinforcing and/or lining excavations, anchoring and connecting devices, and method for using these elements and devices - Google Patents

Abstract

In this slope facing process, facing elements (4) are assembled in situ, their edges having means of jointing with adjacent elements; drainage (D) is provided over the whole height of the face (1) of an excavation between this face and the facing (R) of elements (4) behind which a void-filling material (B) is injected, consisting for example of lean mortar or a swelling material.

Description

The invention relates to a process for coating and / or supporting the walls of natural or artificial excavations such as embankments, banks, trenches, wells, tunnels, etc., according to which anchoring reinforcements are sealed in the floor and covering and / or retaining elements are hung on the sealed reinforcement.

Such a method relates, in particular, to the protection, reinforcement, or stabilization of land.

Various solutions have been proposed to date which, generally, after installation of the covering elements require additional operations such as operations of spraying concrete onto the elements, for example in welded mesh.

The object of the invention is, above all, to provide a method of coating and / or supporting excavation walls which meets better than hitherto the various requirements of the practice and which, in particular, makes it possible to obtain with a minimum of coating operations. It is further desirable that such a process leads to a coating having good soundproofing and sealing qualities and which is aesthetic.

According to the invention, a method of coating and / or supporting excavation walls, of the kind defined above, is characterized in that the coating elements are prefabricated elements which comprise, on their edges, connecting means with the adjacent elements, which these covering elements are assembled "in situ", that there are, over the entire height of the excavation wall, drainage means between this excavation wall and the covering, and finally we put in place a packing behind the assembled prefabricated elements.

Preferably, the prefabricated elements are essentially full, that is to say that the total area of the openings possibly formed in these elements is less than 30% of the total area of the element.

The system of prefabricated elements thus assembled is freestanding under the action of loads (dead weight) and overloads or external stresses (ground pressure, water under pressure, any external forces).

Thanks in particular to this stability, the number of prefabricated elements fixed to reinforcements sealed in the ground (and therefore the number of reinforcements sealed in the ground) can be at most equal to half the number of prefabricated elements.

In the case of prefabricated elements having a hexagonal or circular shape, the number of sealing reinforcements, and therefore the number of prefabricated elements fixed to these reinforcements is equal to one third of the total number of prefabricated elements.

The jam may consist of a lean mortar or a swelling product.

The prefabricated elements can be identical; they can be placed alternately on the front and back.

The connection means between the prefabricated elements can be constituted either by assembly means of the "dry" type such as grooves or notches male and female conjugate, or by assembly means involving a sealant of the mortar type, resin or other, the edges of the prefabricated elements being provided with grooves intended to receive the sealant.

The blocking of the prefabricated elements on the frameworks sealed in the ground is generally carried out after the injection of the tamping.

The invention also relates to prefabricated cladding and / or support elements, in particular for the implementation of a process as defined above, these prefabricated elements being characterized in that, preferably, they are essentially solid, (that is to say that the surface of any openings they can comprise is less than 30% of the total surface of the prefabricated element), and that they comprise, on their edges, means of connection with adjacent elements.

The prefabricated elements, intended to be fixed to sealing reinforcements, may include a reinforced zone provided with a hole for passage of the sealing reinforcement, this reinforced zone being provided in particular in the central region of said element.

The prefabricated elements can have a hexagonal or circular shape. They can be made of concrete, binders or composite materials.

The invention consists, apart from the arrangements set out above, of certain other arrangements which will be more explicitly discussed below in connection with particular embodiments described with reference to the attached drawings, but which are in no way limiting. .

• Figure 1 of these drawings is a schematic cross section of an excavation whose wall is equipped with a coating according to the method of the invention.
• Figures 2 to 7 show, in elevation, various shapes and possible arrangements of the prefabricated coating elements used in a process according to the invention.
• Figures 8 to 14 schematically illustrate various types of connecting means provided on the edges of the prefabricated elements.
• Figures 15 and 16 are diagrams of anchoring devices with self-locking head.
• Figure 17, finally, illustrates another alternative embodiment.

Referring to the drawings, in particular to the figure 1, we can see an excavation E made in the ground S in place and limited by an inclined wall 1. Anchoring frames 2 are sealed in the ground S and protrude from the wall 1, by parts 3 provided at their outer ends s with fastening elements such as a thread capable of cooperating with an appropriate nut Q. Generally , the frames 2 are driven into the ground S with a percussion / vibration machine (not shown); alternatively, a hole can be drilled in the ground, and the reinforcement is introduced into this hole. The frame can be sealed in the ground, which remains in place, with a cement grout or similar product.

Covering elements 4 are hung on the sealed frames 2.

These covering elements 4 are constituted by prefabricated elements which are essentially solid, that is to say that if openings are provided inside the contour of each element 4, the surface of the openings is less than 30% of the total surface of element 4. Preferably, when one or more openings are provided in element 4, each opening has an area less than 1/20 of the total surface of element 4. By way of indication, and in no way limitative , element 4 can have an area of the order of one square meter.

The elements 4 have, on their edges, connecting means L with adjacent elements.

The elements 4 can be flat or curved, for example partially cylindrical.

According to the diagram of FIG. 1, the edges 5 of the elements have, at mid-thickness, a recess 6 so that an edge 7 having a thickness substantially equal to half the thickness of the element, extends beyond the entire outline of the element. With identical elements 4, arranged alternately on both sides, the projecting edges 7 will come to bear against each other as shown in FIG. 10, which will ensure a connection of the elements or panels with each other.

These connecting means L of the "dry" type, essentially formed by an assembly of ribs and grooves, may have shapes different from those shown in FIGS. 1 and 10. For example, protruding elements such as 8 could be provided. (FIG. 8) in the form of a "dovetail" intended to cooperate with corresponding recesses such as 9.

Figure 9 shows another variant of connecting means which can be provided on the edge of the elements 4, and which is constituted by a sort of tongue 10 of circular shape, which is connected by a portion 11 narrowed at the edge of the panel. This tongue 10 is intended to cooperate with a corresponding recess, in the manner of the connecting means provided between the pieces of a puzzle.

According to the variant of FIG. 11, fairly close to that of FIG. 10, the part 7a projecting over the entire periphery of the covering element is limited by a convex-concave surface 12 suitable for cooperating with the convex-concave surface. of the adjacent element arranged upside down.

FIG. 12 represents connection means L of the tenon type 13 provided on the edge of an element and mortise 14 provided on the edge of the adjacent element.

Other embodiments are possible for “dry” type connection means; for example, the edges of adjacent elements could be arranged at right angles to the overall surface of the element, so as to come to cling to the edges of the adjacent element which would have been turned over with respect to the element considered.

Finally, it can be said that in the case of connecting means of the "dry" type, provision is made for combined male and female elements (grooves or notches) either in the plane of the covering element (solution of FIGS. 8 and 9) either in section (solution of Figures 10 to 12).

According to another possibility (Figures 13 and 14), the connecting means L involve a keying by sealant M, of the mortar, resin or other type, between the elements 4a, 4h which have, on their edges, grooves or grooves g, _X intended to receive this sealant. In addition, a strong inclusion such as steel bars, fibers, or the like can be provided in the sealant.

The covering elements 4 or 4a, 4b are assembled "in situ" and are fixed to the end parts 3 of the sealed frames.

The elements 4, 4a, 4b are put in place as the excavation E progresses. As visible from FIG. 1, the elements 4, 4a, 4b are put in place top to bottom.

Because the elements 4 are assembled to each other by means of the connecting means L provided on their edges, the assembled system is self-stable. Advantageously, the number of elements 4 that are fixed on the reinforcements 2 and therefore the number of sealed reinforcements 2, is at most equal to half of the total number of prefabricated elements.

For example, as visible in FIG. 6, in the case of elements 4 formed by panels 15 in the form of regular hexagons, only one panel in three is fixed to a sealed frame 2; the number of frames 2 is therefore equal to 1/3 of the total number of elements 15. The reduction in the number of frames 2 contributes to making the process of the invention economical.

Drainage means D are arranged over the entire height of the excavation wall 1, between this wall 1 and the covering R.

These drainage means D may be constituted, for example, by a draining curtain such as a sheet 16 of fibers, in particular a geotextile sheet unwound along the wall 1. A channel 17 provided with a drain 18 is provided at the bottom of this wall to collect drainage water.

According to another possibility, the drainage means D can be constituted by strainers (not shown) formed by plastic pipes provided with holes in their wall and arranged against the wall 1 while being inclined downwards.

After the installation of the drainage means D, behind the covering R, that is to say in the space 19 between this covering and the wall 1, is injected a stuffing B. This stuffing can be formed by a thin mortar or by a swelling product, or even by sand.

The stuffing B is put in place using holes existing in the elements (either anchoring holes or specific stuffing holes).

When stuffing B has been produced, and after any hardening of this stuffing, blocking is carried out on the sealed frames 2 of the covering elements 4 associated with these frames, this blocking being ensured by relatively moderate tightening of the screwed nuts on the threaded ends of parts 3 of the armatures. When this blocking has been achieved, the heads of the reinforcements and the nuts can be covered by a cover, for example made of concrete, so that the coating R has its finished appearance.

Figures 15 and 16 show anchoring devices with a head in particular self-locking between adjacent elements. According to FIG. 15, the edges 7 of the adjacent elements 4 are inclined substantially at 60 ^{* -} 70 ^* relative to the mean plane of the element. The frame 2 passes between two adjacent edges. A self-blocking head T, made of resistant material (metal, concrete, hard plastic), in the shape of a trunk of a pyramid or a truncated cone, whose wall matches that of the edges, acts like a wedge under the action of the anchoring force, this head T being retained by the nut d. According to FIG. 16, the head T1 is formed by a sort of plate with projecting edges u engaged in the notches provided on the adjacent elements, with possibly self-locking effect.

During assembly, the frames 2 can be provided with an adjustable internal stop w (for example plate metal) (Figures 15, 16), allowing correct positioning of the prefabricated elements.

Advantageously, the elements such as 15 (FIG. 6) intended to be fixed to the sealing reinforcements 2 comprise a reinforced zone 20, of greater thickness, in particular provided in the central region of said element and provided with a through hole for the frame 2. The prefabricated elements 4 can be identical or complementary.

In the case of Figures 2, 3 and 4, the coating R involves different coating elements.

In the case of FIG. 2, there are elements 21 in the form of regular octagons fixed on the frames 2. These elements 21, arranged in a manner similar to the head T1 of FIG. 16, ensure the maintenance of elements of form elongated rectangular 22, 23 oriented in the two orthogonal directions X and Y. The spaces 24 delimited by a contour formed by elements 21 and elements 22, 23 can be open or, possibly, provided with other elements or with own means to retain stuffing B, in the case where the space 24 has a large surface.

According to the example of Figure 3, we find the octagonal elements 21 fixed on the frames 2. These elements ensure the maintenance of prefabricated elements 25 of substantially square or rectangular shape filling all the space between the centers of four elements 21 located at the vertices of a square or rectangle.

FIG. 4 shows a variant according to which the elements 21 of octagonal shape, anchored on the frames 2, ensure the maintenance of other elements 26 of square shape of which one diagonal is substantially vertical and the other diagonal substantially horizontal. These prefabricated elements, of two different types, are coupled to each other in a determined order.

FIG. 5 shows a coating obtained using identical elements 27 substantially of square shape but whose angles have been cut. An element 27, fixed on a frame 2 is arranged "front" while other elements 27 &, adjacent to this element 27 are arranged "back" (in a manner similar to that shown in FIG. 1) to allow the attachment of the connecting means L, of the type shown in FIGS. 10 and 11, provided on the edges of these elements.

FIG. 7 shows an embodiment in which the prefabricated elements 28 have a circular shape. One element in three, as in the case of FIG. 6, is fixed on a connecting frame 2, the distribution of the fixed elements among all the other elements being regular, as in the case of FIG. 6.

The method of the invention allows a rapid coating of natural or artificial excavation walls, having interesting properties on the phonic level, in particular because of the nature of the surface, and on the aesthetic level.

In certain applications, it may be advantageous to place, between the drainage and the packing, a sealing veil.

FIG. 17 shows a variant in which longitudinal elements 4f (vertical, horizontal, oblique) are fixed at several points, on several anchors 2, these longitudinal elements 4f serving to maintain transverse elements 4g ensuring the coating.

Claims (10)

1. Method for coating and / or supporting walls (1) of natural or artificial excavations, such as embankments, banks, trenches, wells, tunnels, etc., according to which anchoring reinforcements (2) are sealed in the ground (S) and covering and / or supporting elements (4) are hung on the sealed reinforcements, characterized in that the covering elements (4) are prefabricated elements which have, on their edges, connecting means (L) with adjacent elements, that these covering elements are assembled "in situ", that there are drainage means (D) over the entire height of the excavation wall (1 ) between this wall and the covering, and that a packing (B) is put in place behind the covering. 2. Method according to claim 1, characterized in that the number of prefabricated elements (4) fixed to the frames (2), and therefore the number of sealed frames (2), is at most equal to half the total number of prefabricated elements. 3. Method according to claim 2, characterized in that the prefabricated elements have a hexagonal (15) or circular (28) shape and that the number of prefabricated elements fixed to the frames (and therefore the number of frames) is equal 1/3 of the total number of prefabricated elements. 4. Method according to any one of the preceding claims, characterized in that the drainage means (D) comprise a draining curtain (16) in particular made of geotextile. 5. Method according to any one of the preceding claims, characterized in that the prefabricated elements are identical and are placed alternately front, back. 6. Method according to any one of claims 1 to 4, characterized in that at least two types different prefabricated elements (21, 25 or 26) are used and are coupled to each other in a determined order. 7. Method according to any one of the preceding claims, characterized in that the connecting means (L) between the prefabricated elements are provided by "dry" assembly means of the male or female grooves or notches type. 8. Method according to any one of claims 1 to 6, characterized in that the connecting means (L) between the prefabricated elements comprise keying by sealing product (M) of the mortar, resin or other product type, the edges of the prefabricated elements being provided with grooves (g, r) intended to receive the sealant (M). 9. Prefabricated elements for coating and / or supporting excavation walls, for implementing a method according to any one of claims 1 to 8, characterized in that they are essentially full (c that is to say that if openings are provided in these elements, the overall surface of the openings is less than 30% of the total surface of the element) and that they comprise, on their edges, connecting means ( L) with adjacent elements. 10. Anchoring device for adjacent elements, for implementing a method according to any one of claims 1 to 8, characterized in that it comprises a head (T, T1), in particular self-locking, retained by a nut (d) on a frame (2) passing between two adjacent edges of the elements.

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