EP1520933B1 - Civil engineering structure - Google Patents

Abstract

The barrier (13) has its face (16) exposed to impacts of moving masses made from individual blocks (1) that can be degraded by impacts and are filled with a material (6) capable of plastic/elastic deformation, e.g. shredded tires, plastic, earth, sand, gravel, stones or crushed concrete.

Description

The present invention relates to a civil engineering structure providing protection against impacts of moving masses, projectiles, especially stones.

State of the art

In mountain areas, as well as in all steep areas, roads, railways, and housing areas are often threatened by falling rocks, landslides, and landslides from cliffs or cliffs. overhanging slopes. Thus, despite regular purges of the cliffs, it is expected in addition infrastructure interposing between the area to be protected and sources of projectiles.

To ensure this protection, we use different types of equipment, including reinforced concrete walls or nets and grids able to retain the stones. There are also works known as "merlons", made for example from gabions or embankments. These merlons are arranged between the cliff and the area to protect, thus defining a ditch in which accumulate stones falling from the cliff. In the case of strong impacts, the exposed side of the merlons may be deformed and damaged. It has been found that these merlons are only very rarely repaired even if they have undergone severe damage.

It is also known from the document FR-2,835,266 the use of used tires coming superadd on the facing of a structure made of concrete. Another solution is known from the document US-A-5,636,938 . All these solutions have disadvantages.

Thus, existing concrete structures have the disadvantage of cracking or being destroyed in the event of impacts by moving masses having a significant kinetic energy. In addition, these infrastructures have much larger dimensions compared to real protection needs. Indeed, it is extremely difficult to diagnose a degraded merlon. This usually leads to over-sizing of the merlon to ensure that it fulfills its protective role after one or more significant impacts.

In the case of a merlon having tires on the exposed face, a repair of such a work requires the complete renovation of the facing and the rear armed merlon in the impacted area. This renovation is a heavy operation, which must be carried out in particularly dangerous sites subject to falling rocks. In addition, the addition of elements with an appearance of waste gives the works an aesthetic that is not necessarily acceptable.

Presentation of the invention

A main problem to be solved by the invention is to provide a civil engineering work that can easily be repaired. A second problem is that of designing a structure with mechanical properties such that it does not require oversizing to perform its protective functions. A third problem is that of improving the aesthetic and ecological aspect of the works while maintaining their functional aspect. A fourth problem is to develop an individual element of construction capable of limiting the damage of the entire civil engineering works with which it is associated. A fifth problem is to achieve an element that can be prefabricated outside hazardous areas, that is to say subject to falling rocks. A sixth problem is that of implementing a method for reinforcing a pre-existing protective structure.

The invention therefore relates to a civil engineering structure, intended to provide protection against moving mass impacts and having a face exposed to moving mass impacts as defined in claim 1.

The structure is characterized in that it comprises, at the level of the face exposed to the impacts of moving masses, a set of individual construction elements joined to each other, completely or partially filled with at least one material having a capacity to be deformed elastoplastically, the individual elements of construction susceptible to be degraded by impacts of moving masses being able to be individually replaced by similar individual elements of construction.

In other words, by directly producing a protective structure comprising individual elements on the exposed facing, the master of work can subsequently extract from the facing individual elements damaged by stone impacts. And it can easily replace them with individual elements undamaged and without breaking the body of the book. Moreover, with the presence of these individual elements facing a cliff, the entire structure will benefit from energy absorption and protection properties. By elastoplastic deformation of a material is meant a deformation of the material associated with its ability to recover its initial shape, up to a threshold beyond which the deformation will be final.

These individual building elements may or may not be associated with various types of structures constituting the body of the overall structure. Thus, according to a first embodiment, the structure may comprise gabions filled with pebbles or fine materials insulated by a geotextile and a set of individual building elements arranged on the face exposed to the moving mass impacts of the structure. .

According to a second embodiment, the structure may comprise an embankment reinforced with geotextile plies, or geosynthetic plies, or double twisted grid plies, or welded mesh or reinforcing steel bars and a set of elements. individual construction arranged on the face exposed to the impacts of moving masses of the structure, and which are connected or not to the reinforcements.

The material having an ability to be deformed may be selected, alone or in a mixture, from the group which may comprise shredded tire pieces, tire cut pellets, pieces of polystyrene, earth materials, sands, gravel, pebbles, recycled crushed concrete, etc. The individual building elements have a first volume of a first material having a capacity to be deformed elastoplastically and a second volume of a second movable material.

The second movable material is intended for example to aesthetically dress the outer face and also to absorb some of the energy. The separation between the two volumes is oriented in a plane substantially perpendicular to the mean direction of arrival of the moving masses, to optimize the energy absorption. during impacts. By soft materials, we mean materials that are deformed and that take a given configuration by splitting or rearranging.

Each individual building element, which forms a container defined by an outer envelope, has a first volume of a first material having a capacity to be deformed elastoplastically and a second volume of a second movable material, the separation between the two volumes being oriented in a plane substantially perpendicular to the mean direction of arrival of the moving masses.

In other words, the individual building and protection element is in two parts or two volumes, each having distinct mechanical properties. The first volume exhibits impact properties of elastoplasticity and the second volume exhibits absorption properties of part of the impact energy. The moving masses arrive on the structure with a preferential direction of arrival and impact. The mean statistical direction of arrival of these moving masses is taken into account, while knowing that rebounds and random trajectories of moving masses can occur. In many cases, the separation plan between the two volumes is substantially vertical.

The first material having an ability to be deformed may be chosen, alone or in a mixture, in the group that may comprise pieces of shredded tires, cut pellets of tires, pieces of polystyrene, earth materials, sands, gravel, pebbles, crushed recycled concrete, etc. The second material, furniture, may be chosen, alone or in a mixture, in the group may include topsoil, sands, gravel, pebbles, blocks of rock, crushed concrete, etc.

The outer casing may be constituted by a cage of a metal gabion, the cage may be, if necessary, covered internally with a geotextile material. The separation between the volume of the material having an ability to be deformed and the volume of loose material can be achieved by a wall of a geotextile material, or mesh, or wire mesh, etc.

The individual building element may also comprise a multiplicity of volumes, successively a volume of a loose material and a volume of one first material having an ability to be deformed elastoplastically. The separation between the volumes can be respectively oriented in a plane substantially perpendicular to the mean direction of arrival of the moving masses.

The civil engineering structure, intended to provide protection against moving mass impacts, and having a face exposed to the impacts of moving masses, is characterized in that it comprises at least two elements as described above.

Thanks to the invention, any impact against the face will affect one or more individual elements of construction, without compromising the structural integrity of the structure.

Brief description of the figures

• les Figures 1 à 4 représentent des vues en perspective de quatre formes de réalisation différentes pour un élément individuel ;
• la Figure 5 représente une vue en perspective d'un ouvrage de protection réalisé à partir d'éléments individuels ; et
• les Figures 6 à 14 représentent des vues en coupe transversales de neuf formes de réalisation différentes pour des ouvrages de protection.

The invention will be better understood and its various advantages and different characteristics will become more apparent in the following description, of the nonlimiting exemplary embodiment, with reference to the appended diagrammatic drawings, in which:

• the Figures 1 to 4 represent perspective views of four different embodiments for an individual element;
• the Figure 5 represents a perspective view of a protective structure made from individual elements; and
• the Figures 6 to 14 represent cross-sectional views of nine different embodiments for protective works.

Detailed description of the invention

As illustrated by Figure 1 an individual building element (1) may be in the form of a substantially parallelepiped gabion. The gabion comprises an outer metal cage (2) made for example, double twist wire mesh or welded mesh. The cage (2) can be closed by a lid (3). Gabions are used to make protective works or to reinforce existing structures.

According to one aspect of the invention, and in a first embodiment (see Figure 1 ), the cage (2) has two distinct volumes (4 and 6). A first volume (6) is located at the front of the cage (2) relative to the closing hinge of the lid (3). A second volume (4) is located at the rear of the cage (2) relative to the closing hinge cover (3).

The first volume at the front (6) contains loose materials, for example pebbles, sands, gravels or topsoil. The second volume located at the rear (4), contains materials with elastoplastic properties, such as pellets or pellets based shredded tires. The first volume at the front (6) is oriented on the protective structure on the side of the face exposed to impacts.

It will be possible to use tire granules obtained by means of the process described in the document FR-2804061 . For example, the pellets used may have dimensions of the order of one centimeter. The shredded tires are maintained using an envelope (7) made, for example, of a geotextile material. A temporary geonatte can also make the separation between loose and elastoplastic materials.

In a second embodiment (see Figure 2 ), the cage (2) also has the same two separate volumes (4 and 6). However, the front face (5) exposed to impacts has an inclination for example substantially equal to 45 ° relative to the horizontal. Such inclined front face (5) will allow a much easier plant implantation, thus giving the cage (2) and all of the work obtained with this type of cages (2) an aesthetic and ecological aspect much more attractive.

In a third embodiment not forming part of the invention (see Figure 3 ), the cage (2) has a single volume (8). This single volume (8) contains materials with elastoplastic properties, such as shredded tires, which are preserved by an envelope (7) made for example of a geotextile material.

In a fourth embodiment (see Figure 4 ), the cage (2) has three distinct volumes (9, 11 and 12). A first volume (9) is located at the front of the cage (2), in this case with respect to the closing hinge of the lid (3). A second volume (11) is located at the rear of the cage (2), in this case with respect to the closing hinge of the lid (3). A third volume (12) is interposed centrally between the first volume at the front (9) and the second volume at the rear (11). The first volume at the front (9) and the second volume at the rear (11) contain loose materials, for example pebbles, sand, gravel or topsoil. The third central volume (12) contains materials with elastoplastic properties, such as shredded tires, which are preserved by an envelope (7) made for example of a geotextile material.

The Figure 5 illustrates a protective structure (13) which is formed of a first stack of metal gabions (14) joined together. These gabions (14) are filled with materials such stones, rocks. The structure (13) is oriented so as to have a vertical or inclined face which is more particularly exposed to falls of stones and other landslides. This structure (13) protects a road (17) and / or dwellings located at the base of the other side of the structure (13), on the opposite side to the exposed face.

According to one aspect of the invention, the structure (13) comprises a cladding (16) made from individual removable structural elements. In this example, gabions inclined front face (1), according to the second embodiment of the Figure 2 , are used. These gabions (1) are arranged relative to each other and with respect to the traditional gabions of the stack (14), so as to present their second volume of soft material (4) exposed front face and to present their first volume elastoplastic material (6) at the rear and against the gabions of the stack (14).

• déterminer le ou les éléments individuels de construction, remplis avec un matériau présentant une capacité à être déformé de manière élastoplastique, qui sont dégradés par des impacts de masses mobiles et devant être réparés ou remplacés (100) ;
• vider ce ou ces éléments individuels de construction (100).
  Pour les éléments individuels de construction à réparer, c'est-à-dire ayant subi un impact local en face avant, sur une faible surface,
• extraire la face avant du grillage qui est détériorée en la découpant ;
• remplacer cette face avant, par ligature ou agrafage, par une face avant intacte, en ayant pris soin de compléter, s'il y a lieu, les matériaux de remplissage.
  Pour les éléments individuels de construction à remplacer, c'est-à-dire ayant subi un impact très important ayant par exemple endommagé la totalité de la face avant,
• extraire (Flèche E en Figure 5) de l'ouvrage de génie civil (13) ces éléments individuels de construction dégradés (100) sans contacts avec les autres éléments individuels de construction non dégradés (1) ;
• ajouter (Flèche A en Figure 5) des éléments individuels de construction intacts (1) à la place des éléments individuels de construction dégradés (100).

According to another aspect of the invention, the gabions of the facing (1) are easily removable and can be replaced if they are damaged. Thus, the method of repairing a civil engineering work (13) may comprise the steps of:

• determining the individual building element or elements, filled with a material having a capacity to be elastoplastically deformed, which are degraded by moving mass impacts and to be repaired or replaced (100);
• empty this or these individual building elements (100).
  For the individual building elements to be repaired, that is to say having undergone a local impact on the front face, on a small surface,
• extract the front face of the screen which is damaged by cutting it;
• replace this front, by ligation or stapling, with an intact front, taking care to supplement, if necessary, the filling materials.
  For the individual elements of construction to be replaced, that is to say having undergone a very important impact having for example damaged the entire front face,
• extract (Arrow E in Figure 5 ) of the civil engineering works (13) these individual elements of degraded construction (100) without contact with the other non-degraded individual building elements (1);
• add (Arrow A in Figure 5 ) intact individual building elements (1) in place of the individual degraded construction elements (100).

Different methods of protective assembly can be implemented on structures. Thus, in a first embodiment (see Figure 6 ), a structure (18) with a stack of gabions (14) comprises a protective covering (19) which is made with gabions according to the first embodiment of the Figure 1 . The structure (18) has a face exposed to falling rocks (21) substantially vertical.

In a second embodiment (see Figures 5 and 7 ), the structure (22) includes a massive structure formed of a stack of gabions (14). It further comprises a protective covering (19) which is made with gabions conforming to the second embodiment of the Figure 2 . The structure (22) has an inclined face (16) which is exposed to rock falls (21) and which can be vegetated.

In a third embodiment (see Figure 8 ) not forming part of the invention, the structure (23) includes a stack of gabions (14) and comprises a central protection core (24) which is made with gabions according to the third embodiment of the invention. Figure 3 . The conventional gabion stack (14), filled with materials usually chosen for a structure according to the state of the art, are located on either side of the stack of protective gabions (24).

In a fourth embodiment (see Figure 9 ), the structure (2) includes a stack of gabions according to the first embodiment of the Figure 1 and according to the fourth embodiment of the Figure 4 .

In a fifth embodiment (see Figure 10 ), the structure (26) has a massive structure formed by an embankment (27), for example made of earth, uniformly reinforced over its entire height by reinforcing layers of geotextile (28) or geosynthetic or lattice or wire mesh . The reinforcing ply (28) extends only over a portion of the thickness of the embankment (27). An inclined protection cladding (29), secured or not to the main structure of the structure, is formed by several longitudinal elements in one piece, which are in accordance with the first embodiment of the invention. Figure 1 . The outer portion (30) of the cladding (29) may be pebbles or top soil or a mixture of earth-pebbles and then vegetated.

In a sixth embodiment (see Figure 11 ), the structure (31) also comprises an embankment (27), for example earth, reinforced evenly over its entire height by reinforcing plies geotextile (28) or geosynthetic or mesh or wire mesh. The reinforcing plies (28) extend in this case over the entire thickness of the embankment (27). The stability of both faces is ensured. An inclined protective face (32) is formed by several longitudinal elements in one piece not forming part of the invention. The outer portion of the facing (32) may be pebbles or top soil or a pebble mixture (33) and then planted.

In a seventh embodiment (see Figure 12 ), the structure (34) is an embankment (27), for example of earth, reinforced in a regular manner over its entire height by geotextile (28) or geosynthetic reinforcement plies or lattice or wire mesh, which extend only on a part of the thickness of the embankment (27), so as to ensure the stability of the slope. The local stability of one of the faces is provided by means of gabions (14) filled with materials usually chosen for a structure according to the state of the art. A protective covering (37) is made with gabions (1) according to the first embodiment of the invention. Figure 1 .

In an eighth embodiment (see Figure 13 ), the structure (38) consists of a vertical stack of gabions (14), filled with materials usually chosen for a structure according to the state of the art, attached to a backfill (27) reinforced by reinforcement plies made of geotextile (28) or geosynthetic or lattice or wire mesh, extending over the entire thickness of the embankment (27), so as to ensure, on both sides, stability of the slope. A substantially vertical protective cladding (39) is made with gabions according to the first embodiment of the invention. Figure 1 .

In a ninth embodiment (see Figure 14 ), the structure (40) consists of a vertical stack of gabions (14) attached to an embankment (27) reinforced by layers of geotextile (28) or geosynthetic or lattice or wire mesh, extending over the whole of the thickness of the embankment (27), so as to ensure, on both sides, the stability of the slope. An inclined protective cladding (41), substantially similar to the facings of the fifth and sixth embodiments of structures (see Figures 10 and 11 ), is formed by a plurality of longitudinal integral elements, which are in accordance with the first embodiment of the Figure 1 .

The present invention is not limited to the embodiments described and illustrated. Many modifications can be made, without departing from the scope defined by the scope of the set of claims.

The dimensions of the protection gabions can be very variable, depending on the desired protection structure. Other applications may be considered, such as protective works in the military field or canal bank reinforcement works, rivers, rivers and seasides, where the masses mobiles are the objects carried by the watercourse, or even traffic lanes, to protect vehicle impacts.

Claims (7)

1. Civil engineering structure, intended for ensuring protection against impacts of moveable masses (21), and having a face exposed to the impacts of moveable masses (21), comprising, in the region of the face exposed to the impacts of moveable masses, a set of individual construction elements, each forming a content delimited by an outer casing (2), characterized in that each individual construction elements as a first volume (6) of a first material having a capacity for being deformed elastoplastically, and the second volume (4) of a second, loose material, the second volume being oriented on the structure, on the same side as the face exposed to the impacts of moveable masses (21), the separation between the two volumes (4, 6) being oriented in a plane substantially perpendicular to the mean arrival direction of the moveable masses (21).
2. Structure according to Claim 1, characterized in that the first material having a capacity for being deformed elastoplastically is selected, alone or in a mixture, from the group comprising pieces of shredded tyres pellets cuts from tyres, pieces of polystyrene.
3. Structure according to Claim 1 or 2, characterized in that the second loose material, is selected, alone or in a mixture, from the group comprising topsoil, sands, gravels, pebbles, rock blocks, crushed concrete.
4. Structure according to any one of claims 1 to 3, characterized in that the outer casing consists of a cage (2) of a metal sheet-pile cell, if appropriate the cage being covered internally with a geotextile material (7).
5. Structure according to any one of claims 1 to 4, characterized in that the separation between the first volume (6) of a first material having a capacity for being deformed and the second volume of a second loose material (4), is implemented by means of a wall consisting of a geotextile material, or of gridwork or of metal latticework.
6. Structure according to any of one of claims 1 to 5, characterized in it comprises a multiplicity of volume, in succession of volume (9, 11) of loose material and a volume (12) of a first material having a capacity for being deformed elastoplastically, the separation between the volume (9, 11, 12) being oriented respectively in a plane substantially perpendicular to the mean arrival direction of the moveable masses (21).
7. Structure (13) according to claim 1, characterized in that the individual construction elements (100) layable to be in damage by impacts of moveable masses (21) are capable of being replaced (EA) individually by similar individual construction elements (1).

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