FR2755985A1 - Coastal defence structure, designed to combat erosion - Google Patents

Abstract

The structure consists of at least one vertical barrier (1) with anchors made from spiked posts, equipped with a supporting platform (4) for weights (6), e.g. in the form of blocks of stone or concrete. The structure can have a single barrier and a lateral stabiliser for the platform, or two vertical barriers (1, 7) situated on either side of the weight platform. The barriers are made from lengthwise planks fastened to the anchoring posts, and the whole structure is made up in the workshop and transported to the required site for erection, which can be carried out with the aid of lifting machines or floats.

Description

COASTAL PROTECTION
The present invention relates to a coastal protection structure and more particularly an elongated structure arranged perpendicularly to the coast or to the edge which it is sought to protect against erosion caused by the sea or by the river or the river.

 This erosion, which results from a scouring of the edges by currents and eddies, is often artificially attenuated by protections put in place to try to reduce or cancel the current.

 Coastal protections are carried out using blocks of stone or concrete dumped by whole trucks in the place to be protected. The works are relatively expensive and do not have a long service life on certain coasts and more especially on muddy coasts covered with sand.

 Other protections have been implemented by means of old boats stranded and sunk on the place to be protected; these defenses disappear fairly quickly in the mud due to their weight. There are also protections of the spike type, arranged perpendicular to the edge to be protected.

These cobs are made up of piles driven into the ground, between which is placed a more or less high cladding. This type of protection is more generally used when one also wants to fatten the place to be protected; it requires good anchoring and therefore is not suitable for muddy ribs.

 The present invention aims to remedy these drawbacks. It offers a stable coastal protection structure in the sense that it does not sink through the layer of sand and then disappears into the mud. The structure is placed and floats on the sand.

 Another object of the invention is to simplify the production and implementation of this type of structure. According to the invention, the structure is prefabricated in the workshop, its implementation on the site requires a minimum of time and resources. In addition, this implementation is simplified by the possibility of adding a temporary float intended to maintain the structure on the water for its installation.

 According to the invention, the coastal protection structure is arranged perpendicular to the coast; it comprises at least one vertical barrier provided with anchoring means, which barrier surmounts a load floor, and it is maintained substantially vertical by at least one stabilizer projecting laterally from said floor.

 According to a preferred arrangement of the invention, the structure comprises two vertical barriers arranged on either side of the load floor; these barriers have slightly different heights and consist of horizontal laths assembled on the anchoring means consisting of posts. These posts are connected transversely to each other by crosspieces which support the floor of loads, which loads consist of blocks of stone or concrete placed between the barriers, on said floor.

 According to another arrangement of the invention, the vertical stability of the barrier (s) is obtained by the crosspieces and it is supplemented by stringers fixed on either side of the floor, and at a good distance, at the ends of said crosspieces. The floor and sill assembly thus ensures low pressure on the ground and offers good horizontal stability.

 The invention will be better understood with the aid of the description and of the appended drawing given for information.

 The structure shown in the appended figure is placed perpendicular to a curb bordered by the sea at high tide. Like the shoreline, this type of pavement is sensitive to scour at the edge caused by the current. Protection is achieved by a first barrier 1 consisting of horizontal wooden planks 2 fixed on posts 3 sunk into the ground. Behind this first barrier, a wooden floor 4 is also placed, placed on crosspieces 5. These crosspieces are assembled on the posts 3 and extend widely on each side of the floor. Loads 6 made up of blocks of stone or concrete are placed on the floor, sandwiched between the first barrier 1 and a second barrier 7, lower than the first. This second barrier 7 is made up of horizontal planks 8 fixed on posts 9 anchored in the ground. These posts 9 are integral with the same crosspieces 5 as the posts 3. The struts 10 are disposed between the posts 3 or 9 and the crosspieces 5. The end of the floor, opposite the edge of the shore, is closed by planks 11 for retaining, if necessary, the loads disposed on said floor; these boards are fixed to the end posts. The horizontal stability of the floor, and thereby the vertical stability of the barriers, are produced by the crosspieces 5 which extend on either side of the floor over a length substantially equal to or greater than the height of the first barrier. This stability is supplemented by stringers 12 arranged parallel to the floor, on each side, on the ends of the crosspieces 5.

These sills 12 are wooden planks arranged and fixed flat under the sleepers.

 The installation of these works can be carried out by conventional lifting devices. The location will be slightly prepared if necessary so that the floor is horizontal on the floor. The establishment may also be carried out when the sea is not completely withdrawn, by means of floats and more particularly of a float provisionally fixed under the opposite end to that which will remain at the edge so that the structure is pushed from the roadway in its final position; the float is then removed and the loads are placed on the floor.

 The invention is in no way limited to the specially indicated embodiments, but it also covers all the possible variants provided that these are not in contradiction with the subject of each of the claims annexed to this description. Thus, the barriers which, as shown, comprise respectively three boards for one and two boards for the other, can be higher with a greater number of boards.

 We can also plan to raise the barrier, on the side of the edge to be protected, with one or two additional planks that will follow the natural slope of the ground.

Claims (6)

- CLAIMS  1.- Coastal protection structure, arranged perpendicular to the edge to be protected, characterized in that it comprises at least one vertical barrier (1) provided with anchoring means, which barrier overcomes a floor (4) of loads (6 ), and it is kept substantially vertical by at least one stabilizer projecting laterally from said floor.  2.- coastal protection structure according to claim 1, characterized in that it comprises two vertical barriers (1 and 7), arranged on either side of the floor (4) of loads.  3.- coastal protection structure according to any one of claims 1 or 2, characterized in that the barriers consist of boards (2) fixed horizontally on the anchoring means consisting of posts driven into the ground.  4.- coastal protection structure according to claim 3, characterized in that the posts are integral with the crosspieces (5) horizontal projecting from each side of the floor (4) which they support.  5.- coastal protection structure according to claim 4, characterized in that it comprises sills (12) disposed on each side of the floor (4) and fixed to the ends of the sleepers (5).  6.- coastal protection structure according to any one of claims 1 to 5, characterized in that the end of the floor (4) is closed.