EP1308562B1 - Net- or mesh- structure for erosion protection - Google Patents

Abstract

The ground erosion prevention grid has a mesh container (10) which is filled with stones on site. The container has lateral walls (11) and an upper cover <??>(13). The base (12) has an overhanging skirt (14) on at least one side. When the container is placed, the skirt is overlapped with the skirt of an adjacent container. <??>An Independent claim is also included for an erosion prevention method using the grid

Description

The present invention relates to a structure of mesh or lattice container for protection against erosion. The invention has been developed for the use of container structures, for example cages or gabions, in an underwater environment for protection against erosion of watercourses, and more particularly from bed and river banks, canals and the like, essentially as alternatives to traditional rockfill protection. The invention can also be adopted for the protection of batteries bridge in river, and for the protection of downstream riffles thresholds or dams and the like.

Structures have long been used parallelepipedic made of mesh mesh hexagonal metal double twist, in covers and as protective structures to prevent soil erosion, see for example US-A-5,161,917 or US-A-4,726,708. The container structures described in EP-A-0 735 198 and US-A-4,572,705 are of the replicable type. . The said structures used for aquatic applications are preferably consisting of multi-cell mesh cages Metallic divided into compartments by diaphragms of the same nature and filled with stones, pebbles and similar. Commonly called cell gabions multiple, they are placed side by side on the bottom of the bed of the river without any ligation or connection between them, when the laying operation is carried out under water. By therefore these multiple-cell gabions are at risk to be posed approximately in view of the difficulties underwater, to move slightly to any moment and thus offer them sufficient space to allow the current to erode the bottom parts that are no longer protected. These gabions do not offer a total guarantee of anti-erosive protection.

The objective of the present invention is therefore to solve the disadvantages of the known technique, providing an improved product preventing the said risks erosion between the elements. Another goal of the invention is to provide a product designed to meet this need while optimizing its implementation on the yard, often carried out under difficult. A final objective of the invention is guarantee a result guarantee for the protection against erosion while providing a reliable and sustainable in time, with the greatest simplicity of use and manufacture while guaranteeing high degrees of resistance and stability to the set protected area.

These objectives are achieved by means of a structure Container mesh or lattice for protection against erosion, where the structure will be filled with pebbles or with another construction material. This product includes a base or bottom, walls or side panels and an upper part or cover, and the base has an overhang or skirt on at least one side. The extension skirt extends over at least two adjacent sides of the base.

According to one aspect of the present invention, the skirt solidly attached to the base of the cage or gabion is preferably, but not exclusively, in wire mesh hexagonal double-twist, doubled on or under the face of a geotextile or a protective material preventing leakage of particles from soil in the event of exposure to hydraulic stresses. In this way the extension skirt is sufficiently rigid to be laid flat and fold-free on the bottom, everything is subsequently covered by the structure of the neighboring gabion to ensure effective bottom protection of the riverbed in the contact zone between two gabions.

The product according to the present invention is thus perfectly indicated and adapted for implementation in aquatic environment for the realization of anti-erosive protection to perform under water. This solution is easy to implement, and has the advantage of dispensing ligate and assemble the gabions together while at the same time ensuring good protection between gabions.

• la figure 1 est une vue en perspective d'un mode de réalisation d'un gabion à cellules multiples amélioré selon la présente invention,
• la figure 2 illustre un usage typique des deux gabions améliorés juxtaposés et en contact,
• la figure 3 illustre les deux gabions de la figure 2 en cas d'écartement, dû par example à un défaut de mise en oeuvre ou à un mouvement de la protection en cours de service.

Other characteristics and advantages will be better understood on reading which follows from an exemplary embodiment and with reference to the accompanying drawings given solely by way of example, in which:

• FIG. 1 is a perspective view of an embodiment of an improved multi-cell gabion according to the present invention,
• FIG. 2 illustrates a typical use of the two improved gabions juxtaposed and in contact,
• Figure 3 illustrates the two gabions of Figure 2 in case of separation, due for example to a lack of implementation or a movement of the protection during service.

We will now refer to the figures on which has been designated as a whole by 10 a structure of container or envelope according to the present invention, for example a gabion or a cage in mesh or lattice. This gabion 10 comprises a parallelepipedic structure, preferably made of wire mesh, with walls or side panels 11, a base or bottom 12 and a cover 13. The base 12 has an overhang (extension skirt) 14 on at least one side, and preferably at least two adjacent sides. The base 12 and its overflow 14 are of the same nature and are lined on the underside or covered with a geotextile or protective material preventing leakage of particles soil in case of exposure to the current. Gabion 10 is preferably divided into cells by walls intermediaries or diaphragms 16.

According to one embodiment of gabion 10, the base 12 and its overhang 14 are formed by a single sheet rectangular having a hexagonal mesh structure preferably formed by a double-twisted mesh in wire coated with a zinc alloy and aluminum, known under the trade name GALFAN®, and plasticized by example with a PVC coating or a material similar. The outer edge 14 forms one and the same piece with the base 12 of the gabion. When the overflow 14 extends over at least two adjacent sides of the gabion, it There are "right" overhangs and "left" overhangs in according to the construction provisions of the site. All the side walls 11 and intermediate 16 are preferably made of double twist wire mesh, and are assembled at the base 12 of the gabion, if they must to be, preferably in the factory.

We can also make gabion 10 at least partially by folding from a single layer of grid, constituting the base 12 with its overflow 14 and two of the opposite sides to the overhang 14. In this case, both side walls 11 contiguous to the overhang 14 are assembled in the factory by stapling or by a method of manufacture similar.

The lid 13, independent of the structure of the base 12 and side walls 11 and intermediate 16, is preferably made by a single layer of fence. It can, in the case of important sections rectilinear, be replaced by a roll of wire mesh having the same mesh and the same characteristics as the wire mesh constituting the base and walls of the gabion.

The geotextile 15 is placed entirely under the overhangs 14 and partly overflow under the base 12; this operation can be performed preferably in factory by mechanical stapling.

During the implementation, the gabions or cages 10 are completed according to the rules of art, so as to ensure homogeneous filling and minimize the empty. Multi-cell gabions can be shaped in different ways, thus allowing by folding, overlapping or juxtaposing curves.

Banks, embankments or river beds likely to be protected using gabions with overhangs according to the present invention are previously cleaned, reprofiled and regaled to be free of all depressions or asperities, branches, stumps or others. We will be able to where appropriate, localized reloading in areas that are too hollow to respect the regularity of ceilings.

For work in the presence of water, gabions 10 are mounted, filled and closed ashore on a prefabrication provided for this purpose. In a second step, gabions 10 are transported and handled for be installed in their final location. We will bring also a particular care to the flattening of overhangs 14 on the ground without damaging the geotextile 15 in under face. To avoid kidnapping and training fines under the gabions 10 due to the solicitations residual hydraulics, interposed between the soil and the gabion 10 a nonwoven geotextile filter of the known type or any other process with the same function. This geotextile is installed in the cage before filling, which is realized with the materials defined previously, followed a manual superficial finishing arrangement.

After completion of the filling of the gabions 10, the free edges of the lid are adjusted and positioned above the edges of the corresponding gabions. For the fastening the covers, we will first make the stapling edges of the perimeters (with special care for corners) and then diaphragms.

The gabions 10 are then transported to the place their implementation by appropriate means, which will have to be be designed in such a way that the handling of gabions does not cause or little deformation of the structure, and that every gabion is raised in several points without risk of injury to the wires, or work rate high in the metal wires. The filled structure may for example be moved using a rudder or other known handling means clinging to a lifting device such as straps or other distributed way the efforts in charge of the gabion.

The gabions 10 are then put in place and juxtaposed in underwater environment so that spaces between each gabion 10 are best limited in their final location. We must make sure to cover the overflow 14 of each gabion 10 through the gabion cage neighbor, as illustrated in Figure 2.

When a current will discard two gabions 10 neighbors, zone 17 discovered between them (see Figure 3) remains protected by overflow 14, while avoiding the erosion of bed of the river below the geotextiles 15. In this situation, the anti-erosive protection between Gabions is provided by the overflow.

Of course, various modifications and variants may be made by those skilled in the art to the device which has just been described as an example only limiting without departing from the scope of the invention as defined in the claims.

Claims (11)

1. A net or mesh container structure for use on a site, for protection against erosion, where the structure (10) will be filled with stones or some other building material, and comprising lateral walls (11), an upper part or lid (13), and in which the base (12) has an extension skirt (14), characterized in that the skirt (14) extends on at least two adjacent sides of the base (12).
2. A container structure according to claim 1, characterized in that the skirt is of the same nature as the container structure.
3. A container structure according to claim 1, characterized in that said structure is metallic or synthetic.
4. A container structure according to claim 1, characterized in that the lateral walls (11), the upper part (13) and the base (12), except for the skirt (14), form a parallelepiped or gabion cage.
5. A container structure according to any one of claims 1 to 4, characterized in that the internal volume of the structure is divided into cells by intermediate walls or diaphragms (16).
6. A container structure according to any one of claims 1 to 5, characterised by a lining material (15) beneath or on at least the skirt (14) for preventing the particles of soil protected underneath from being carried away in the event of exposure to current velocities.
7. A method for manufacturing a structural block on a site, characterized in that a container structure according to any one of claims 1 to 6 is brought onto the site when in the folded form, is set up on the site, and is filled with solid material.
8. A method according to claim 7, characterized in that the solid material is held in the structure by the meshwork of the net or mesh of the cage.
9. A method according to claim 7, characterized by the application of a lining material to the structure after it is set up on the site, the solid material being held in the structure by the lining material.
10. A method according to claim 7, characterised in that said filling material is selected from any one or any mixture of sand, rubble, aggregate, concrete, earth, stones, clay and the like.
11. A method according to claim 7, characterized in that after the filling of at least two separate structures (10), said at least two structures (10) are placed next to each other in the place where they are to be used, the skirt (14) of one of the two structures (10) in their final location being covered at least partially by at least part of the neighbouring structure (10).

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