FR2788798A1 - Stabilizer for sandy-bedded coast for naval architecture has walls, forming inverted V, extended with lateral vertical walls securing structure to coast bottom - Google Patents

Abstract

Stabilizer (1) is made with reinforced concrete and has two upper inclined walls (10, 11) forming inverted V-shaped area. Wall (10) is placed parallel to bottom of coast. Walls are extended with lateral vertical walls (12, 13) sunk in sand (sa) to secure stabilizer to bottom of coast.

Description

SIDE STABILIZING ELEMENTS AND ENGINEERING WORK

MARITIME CONSISTS OF SUCH ELEMENTS

  The present invention relates to a stabilizing element

  rib, especially a sandy coast or

made of similar material.

  The invention also relates to an engineering structure

  maritime based on such elements.

  It is well known that certain coasts, subjected to the force of the waves breaking on them and to more or less violent currents, degrade. These degradations are often very significant and rapid when the material of which they are composed is essentially based on sand or the like. There is therefore a real need to stabilize this type of coast. In addition, marine engineering structures must resist waves (slap effect). They must therefore be made of very solid materials, to avoid rapid degradation and erosion, but also to resist

  pressure forces tending to tip them.

  The invention aims to fulfill this need and proposes modular elements which, when assembled, will allow the

  construction of a stabilizing structure.

  More precisely, the invention sets itself the aim, simultaneously: - of stopping the waves arriving from the open sea and of tranquilizing the water in an area close to the beach; - allow the deposit of sand on this beach or near it;

  - and to slow down and / or stop the coastal transit.

  To do this, the invention provides hollow modular elements comprising two inclined upper walls, extended by two vertical walls. One of the inclined walls faces outwards, the other is

  substantially parallel to the coast line.

  According to a first important characteristic of the invention, the vertical walls are intended to be driven into the material making up the sea floor, so as to obtain an anchorage ensuring good stability and to remain insensitive to variations in this background, or for the

  less sensitive to these variations.

  Preferably, an internal horizontal longitudinal slab is also provided, arranged at the junction of the inclined wall parallel to the coast line and the vertical wall extending it. This horizontal slab is intended to be placed on the bottom of the sea

  and contributes to the good stability of the whole.

  According to another important characteristic of the invention, slots or openings are provided in one of the inclined walls, more precisely in the inclined wall facing outwards. These slots facilitate the hydrostatic balance between the exterior and

  inside the stabilizing element.

  The stabilizing elements also include interlocking members in each other, so as to place them side by side to build a work of engineering

maritime coast stabilization.

  Preferably, this structure consists of solid sections comprising several elements according to the invention, separated by empty zones. The relative lengths of the sections and the empty zones, as well as the distance separating the structure from the low water line of the coast are such that they allow deposits of sand, or other similar materials, overlapping behind the obstacle, which authorizes the reconstruction of the beach

after construction of the structure.

  The subject of the invention is therefore a stabilizing element for a rib exposed to water turbulence, the material forming the bottom of said rib being sand or a similar material which can be moved by said ribs.

  turbulence, characterized in that said stabilizing element

  tor comprises two inclined upper walls, so as to form an inverted "Vee", one of the walls, called the rear, being intended to be arranged parallel to said rib and the other being said before, and in that said upper walls inclined are each extended by a vertical side wall intended to be embedded in said material, so as to anchor said stabilizing element

on the bottom of the said coast.

  The subject of the invention is also a maritime engineering structure for the stabilization of a sandy coast or composed of similar materials, consisting of at least one

assembly of such elements.

  The invention will be better understood and other characteristics.

  ristics and advantages will appear on reading the

  description which follows with reference to the appended figures,

  among which: FIGS. 1A and 1B illustrate an example of a stabilizing element according to a preferred embodiment of the invention, in perspective and in side view, respectively; - Figure 2 illustrates, in perspective, an assembly of several elements according to Figures 1A and 1B; - And Figures 3A and 3B illustrate a complete maritime engineering work comprising several assemblies of stabilizing elements. We will now describe in detail an example of stabilizing element 1, according to a preferred embodiment of the invention, with reference to

Figures lA and lB.

  It will be assumed in what follows that the coast, to be protected and stabilized, is essentially composed of

sand, referenced Sa.

  The element 1 has two inclined upper walls, 10 and 11. The wall 11, or front wall, intended to be turned facing offshore, advantageously has a

  slope more gentle than the slope of the rear wall, 10.

  The stabilizing element 1 also has vertical walls, 12 and 13, extending, downwards, the walls

  inclined, 11 and 12 respectively.

  Advantageously, an internal horizontal slab 14 is provided, running substantially over the entire length of the element 1. This slab 14, of small width compared to the total width of the element 1, is arranged on the rear of element 1, substantially at the intersection

walls 10 and 13.

  According to a first important characteristic of the invention, the vertical walls, front 12 and rear 13, are driven into the sand Sa. The friction of the walls offers resistance to tilting. The slab 14 lies flat on the bottom of the sea. These provisions provide good stability and allow to be insensitive, in

  large proportions, varying from the bottom of the sea.

  According to another important characteristic of the invention, slots 110 are also provided in the inclined wall 11, that is to say the one intended to

  be turned towards the open sea.

  It is clear that a complete structure does not in practice include only one stabilizing element. Such a structure, as will be shown below, consists of several elements joined together. Also, it is advantageous to provide cutouts, 111 and 112, on the right and left edges of the wall 11. These cutouts have the same length as the slots 110, but a width substantially equal to half the width iF of those -this. Therefore, once two elements 1 are arranged

  side by side, the slit, which will be called composite, 111-

  112, joining these two elements, will have the same width

than the central slots 110.

  The central slots 110 (or the composite slots 111-112) facilitate a hydrostatic balance between the exterior of the element 1, when it is inserted in the sand and immersed in water, and the interior of the latter. . Indeed, there remains an enclosure of substantially triangular section delimited by the internal faces of the walls.

  upper, 10 and 12, and the Sa sand (sea bottom).

  Finally, to facilitate the assembly side by side of the elements 1, provision is made for interlocking members of complementary shapes. These elements are arranged along the rear inclined wall 10. In the example described, there is provided a rebate 100 laterally extending the wall 10, on its left, and a lateral groove 101 dug in this

  same wall, but on its right side.

  Figure 2 illustrates an assembly of four elements arranged side by side and joined to each other by the aforementioned complementary members. The elements common to the previous figures have the same references and will only be described again as necessary. The references are only supplemented by indices, a to d, each associated with one of the four stabilizing elements,

  the to ld. In addition to the assembly and nesting possibilities

  ment (0l1a-10Ob to 101c-100d) of the various stabilizing elements, la to ld, Figure 2 clearly illustrates the constitution of the composite slots, for example llla-112b, which are inserted regularly between two series of

  central slots, for example 110a and 110b.

= i T -

  The dimensions and nature of the modular stabilization elements naturally depend on the application

  precise envisaged, i.e. essentially of the envi-

  ronnement, and in particular the swell taken into account offshore, the peak-to-peak speed of the waves, the slap effect, the currents, the hydrostatic force and the rocking force exerted on the element. These data are

obtained by experimentation.

  To fix ideas and without this being limiting in any way of the scope of the invention, we will

  specify a practical example below.

  Element 1 is made of reinforced concrete and the walls are 25 cm thick. The overall length (outer face of the two vertical walls, 12 and 13) is 7.50 m, the projections on a horizontal surface of the upper walls, 10 and 11, being equal to 1.5 m and 6 m, respectively, their respective inclinations being approximately 60 and 30 degrees. The height of the vertical walls, 12 and 13, is 2 m, and their width 2.5 m. The slots, or 111-112, cover almost the entire wall 11 and

  have a length of 5.4 m, for a width of 20 cm.

  Naturally the notches 111 and 112 have an individual width of 10 cm. In the example described, the groove 101 has a depth of 10 cm. Similarly, the rebate 100 laterally protrudes from the wall 10 over this same distance, to

authorize embedding.

  From the modular elements that have just been

  described, we will be able to build stabilized structures

  coast guardians. To do this, the stabilizing elements 1 are assembled in one or more rows, arranged

parallel to the beach.

  Such a work is illustrated by FIGS. 3A and

  3B, in side and top views, respectively.

  In the example described, it is assumed that the stabilizing structure 3 comprises two rows, 3a and 3b, of stabilizing elements 1, assembled in line, side by side joined together. These two rows, 3a and 3b, form obstacles to the currents and the movements of the waves, and are separated by an empty zone Zv. This breach gives free passage to the water, but also authorizes the arrival and deposit of sand on the beach or in the immediate vicinity of it. This sand is deposited in areas located behind the rows of stabilizing elements 3a and 3b, so-called tranquilized areas. Preferably, the rows 3a and 3b are implanted substantially parallel to what will be called the coastline TC, that is to say the top of the range. The distance d separating the structure 3 from the low water line 1BE, the length lzv of the empty zone ZV separating two successive rows, 3a and 3b, of stabilizing elements 1, as well as the lengths, la and lb, of obstacles individual formed by these rows, are determined so that the materials are deposited in two deposition zones, Zda and Zdb, with a large overlap. This arrangement makes it possible to obtain a deposition strip of relatively uniform width. Assuming that there are significant variations in sea level due to the tides, it is also arranged for the mean level of the waters Nmoy to be substantially exposed at the top of the stabilizing elements 1, as shown

  more particularly FIG. 3A.

  The waves, and possibly entrained sand, slide on the front inclined walls (Figures 1A and 1B: 11), gently sloping, and the materials entrained, whatever the mode (by the breach formed by the empty zone ZV or at - above obstacles, 3a and 3b), are retained in the tranquilized zones, behind the stabilizing elements 1. A reflux of the waves is made more difficult by the steeper slope of the rear walls (FIGS. 1A and 1B: 11). The gentle slope of the front walls 11 of the stabilizing elements 1 also makes it possible to break the waves and

  transform turbulence into laminar flow.

  Although the numerical values characterizing such a structure depend essentially on the configuration of the coastline to be equipped: slope of the beach, etc., and, as indicated, local maritime conditions: amplitude of the tides, etc., typical values are as follows: distance separating the structure from the low water line: d = 80 m; lengths of individual obstacles: la = lb = 80 to m;

  - width of the empty area: lzv = 70 m approximately.

  The stabilizing structure 3 consists of stabilizing elements 1, the dimensions of which were previously

specified as an example.

  On reading the above, we can easily see

  that the invention does achieve the goals it has set for itself.

  It should be clear, however, that the invention is not limited only to the examples of embodiments explicitly described, in particular in relation to FIGS. 1A to 3B. In particular, the numerical values have been specified only to fix ideas. They essentially depend on the precise application targeted. Likewise, the number of slots made on the inclined upper wall facing the sea is not limited. We could, for example provide three slots on each element, and no slots at the junctions, so-called composite slots. The slots were assumed to be perpendicular to the edge between the inclined upper walls, which has the advantage of allowing passageways between the exterior and

  inside the stabilizer even when

  it is not fully submerged. On the other hand if it is permanently submerged, there is nothing to prevent the slots

are horizontal.

  The materials that can be used are essentially linked to the specific application envisaged and participate in a

  simple technological choice within the reach of those skilled in the art.

  It should also be clear that, although particularly

  Lely adapted to the protection and stabilization of a sandy coastline, exposed to sea swell, the invention cannot be confined to this only type of application. It applies equally well to the protection of the banks of a lake or an inland sea. Sand is not the only material that can be moved by movement

waves or currents.

Claims (8)

  1. Stabilizing element of a rib exposed to water turbulence, the material forming the bottom of said rib being sand (sa) or a similar material which can be displaced by said turbulence, characterized in that said stabilizing element (1 ) comprises two inclined upper walls (10, 11), so as to form an inverted L "Vé", one of the walls (10), called rear, being intended to be arranged parallel to said rib and the other being said front, and in that said inclined upper walls (10, 11) are each extended by a vertical side wall (12, 13) intended to be pressed into said material (sa), so as to anchor said stabilizing element (1) on the bottom of the said coast. 2. stabilizing element according to claim 1, characterized in that said front upper wall (11) is provided with at least one opening (110, 111-112), so as to ensure a hydrostatic balance between   the exterior and interior of said stabilizing element (1).   3. stabilizing element according to claim 2, characterized in that the slope of said front inclined wall (11) is less steep than that of said wall rear (10).   4. Stabilizing element according to any one of   previous claims, characterized in that it is   provided with a horizontal slab (14) of small width, disposed near the junction between said rear inclined upper wall (10) and said vertical wall (13) extending it, and in that this slab (14) runs along said vertical wall (13) and is intended to lie flat on said bottom, when said vertical walls   (12, 13) are embedded in said material.   5. Stabilizing element according to any one of   previous claims, characterized in that said   rear inclined upper wall (10) is provided with means   side fitting of complementary shapes (10Oa-   lOla à lOOd-10ld), so as to assemble and nest, two by two, said elements (la to ld), by placing them side by side, to achieve linear arrangements   adjoining stabilizing elements (1).   6. Maritime engineering structure for the stabilization of a coast, characterized in that it comprises at least one row (3a, 3b) of stabilizing elements (1) according to one   any of the preceding claims, forming a   obstacle to said turbulence, said elements (1) being placed contiguously, contiguously, in line substantially parallel to said rib, and in that said vertical side walls (12, 13) are embedded in said material (Sa), so as to anchor said elements stabilizers (1).   7. marine engineering structure according to claim 6, characterized in that, said stabilizing elements (1) being immersed in a body of water whose level is variable, these are arranged at a distance (d) from the line marking a so-called low water level (1BE) such as the average level (Nmoy) of said   variations outcrop at the top of said "Vé".   8. A marine engineering structure according to claim 7, characterized in that it comprises several rows (3a, 3b) of stabilizing elements (1) forming obstacles to said turbulence and separated by zones (ZV) empty of stabilizing elements. , so as to allow the penetration of water transporting said material and its deposition behind said rows (3a, 3b), in so-called tranquilized zones, and in that the relative lengths (la, lb) of said rows (3a, 3b ), empty zones (ZV) and said distance (d) separating the stabilizing elements (1) from said line marking the low water level (1BE) are determined to obtain a recovery of said deposits (Zda, Zdb) for two consecutive rows (3a, 3b), so as to create a band of deposits of said material at the edge of the rib of substantially uniform width. -TT rnr