STRUCTURE FOR PROTECTING SEA AND/OR RIVER CONSTRUCTION WORK, AND PROTECTIVE BLOCK USED

Abstract

The invention relates to a structure for protecting sea and/or river construction work, which uses blocks (1) including a central core (2) having an upper portion (4) and a lower portion (3). The central core (2) is surrounded, in the lower portion thereof (3), by a circular projection (5) including side surfaces (9) and is capable of abutting, by means of at least one of the side surfaces (9), at least one of the side surfaces of a circular projection of an adjacent block.

Description

The present invention relates to an armor layer of a protective structure for sea and/or river construction work against waves and currents comprising a plurality of artificial blocks.

Among the different components that make up a protective structure for sea and/or river construction work, the armor layer is the key element for ensuring the stability of the structure and is the main protective element in the structure against swells. The armor layer can be made of natural riprap or artificial blocks, usually made of concrete.

Numerous studies have been carried out to develop effective artificial blocks, with a view primarily to proposing optimized shapes resulting in high robustness, as well as high hydraulic stability, thereby reducing the amount of concrete required and consequently costs. However, it is generally recognized that increased robustness results in reduced stability, and vice versa.

Stability depends on the ability of the blocks not only to engage with the slopes beneath the construction work to be protected, but also and primarily to be assembled together using the specific form of the blocks, forming a protective armor layer that leaves sufficient empty spaces to absorb the hydraulic energy to which the construction work is subjected.

Robustness is the mechanical strength of the blocks against shocks, stresses and erosion, provided by the shape of the blocks. This shape also determines the interconnection properties of the blocks and the void ratio of the armor layer. This ratio must be high enough to disperse the energy of the waves and to reduce the action of uplift pressure.

In particular, the armor layer may settle over time and under the effects of the stresses caused by the swell and the current, and the blocks may begin to oscillate between two positions, which accelerates degradation of the armor layer.

Blocks that have a slender shape improve the individual stability of the elements and resistance against overtopping. However, such blocks provide low structural strength, which may lead to rapid degradation of the armor layer.

Blocks that have a less slender shape, i.e. larger blocks, with protuberances intended to increase interconnection with adjacent elements, generally provide high hydraulic performance. However, to guarantee the stability of the structure, such blocks usually have to be laid according to stringent layout rules, which makes the armor layer time-consuming and difficult to build. Such difficulty notably results in a relative variability in the performance of these blocks.

It is also known to use blocks with a square core and pointed protuberances at each corner, and a protuberance on each face of the square. However, these protuberances are fragile parts that are susceptible to damage, notably because they are points of contact or support between adjacent blocks.

One objective of the invention is to improve the performance of a protective structure, notably in terms of dissipation of swell energy, using blocks providing high structural strength that can be laid in an arrangement that is easy to build and provides uniform porosity.

For this purpose and according to a first aspect, an armor layer of a protective structure for sea and/or river construction work comprising a plurality of protective blocks is proposed. Each protective block has a central core having an upper portion and a lower portion. The lower portion of the central core is surrounded by a circular protuberance having lateral faces that is able to butt, via at least one of the lateral faces, against at least one of the lateral faces of a circular protuberance of an adjacent block.

The presence of the circular protuberance enables the blocks to be arranged easily together, notably making it possible to include a minimum distance between the central cores of two adjacent blocks, as well as making it easy to partially pave the underlying surface of the slope, making it possible to protect same and to encourage the flow of water over the top. Furthermore, the upper portion of the central core makes it possible to absorb a portion of the energy of the swell, encouraging dispersion of the water when the swell hits the block. The upper portion of the central core therefore acts as a dissipation element and the upper portions of the different blocks provide the armor layer with a rough envelope that limits the amplitude of the movements of the swell on the armor layer, in particular due to the spaces created about the upper portions of the cores by the circular protuberances. With an orderly or random layout plan, it is easy to obtain a uniform distribution of the blocks and of the upper portions of the blocks, and a uniform porosity in the armor layer. Furthermore, the shape of the circular protuberances permits arrangements having openings arranged regularly between adjacent blocks, which facilitates transverse flows that increase the stability of the blocks.

Preferably, the circular protuberance can provide partial paving of a surface with adjacent protective blocks in contact with one another via at least one of the adjacent surfaces of the circular protuberance. The partial paving may vary between 60% and 90% of the surface on which the blocks are laid, preferably between 70% and 85%.

The central core may have a lower base and an upper base, which are preferably flat, the lower base and the upper base being square or octagonal and joined by the lateral faces. The circular protuberance may be arranged about the lower portion of the lateral faces of the core, from the lower base of the central core.

The core is preferably a square- or octagonal-based right prism.

The circular protuberance may have an octagonal lateral contour. The circular protuberance may have a square lateral contour having a notch on at least one of the sides, the notch being able to cooperate with a vertex of the square lateral contour of a protuberance of an adjacent block. Thus, in the case of an octagonal lateral contour, adjacent blocks are in contact with one another by at least one of the lateral faces of the protuberance. In the case of a square lateral contour, adjacent blocks are in contact via the vertexes of the contour and the notches of the sides of the contour. In both cases, the contact surfaces improve the stability of the blocks between one another, and the geometry of the circular protuberance makes it easy to position the blocks in relation to one another.

The octagonal lateral contour may be a square lateral contour in which the vertexes are chamfered. In this case, the lateral contour is not a regular octagon, but every other lateral face has a smaller surface.

Preferably, the circular protuberance forms, with the lower base of the core, a preferably flat lower surface of the block. Said lower surface of the block is the surface on which the block rests on the underlying slope.

Preferably, the circular protuberance also has a circular surface that is inclined, for example to between 0° and 70° and preferably to between 5° and 65°, joining the upper extremity of the lateral contour of the circular protuberance to the lateral faces of the core. Such an inclined surface facilitates manufacture of the block, in particular by casting, and also makes it possible to obtain a more robust block.

The perimeter of the lateral contour of the circular protuberance may diminish in the vicinity of the lower surface of the block 1.

The height of the circular protuberance may constitute between 25% and 85%, preferably between 40% and 70%, of the total height of the block. The width, notably minimal, of the upper portion of the central core may constitute between 40% and 95%, preferably between 50% and 75%, of the total width of the block 1.

The circular protuberance may have vertical grooves on the lateral faces of same.

The protective block may have at least one vertical through-hole. It may also have at least one horizontal through-hole. These holes facilitate the flow of water within the armor layer, in particular the flow of water towards the sea or the ocean.

According to a second aspect, a protective structure for sea and/or river construction work comprising a plurality of blocks according to the first aspect is proposed. The structure may include a central element, at least one filter layer and one armor layer comprising a plurality of blocks according to the first aspect.

Preferably, the blocks form partial paving covering between 60% and 90%, and preferably between 70% and 85%, of the surface on which the blocks are laid.

The invention is further described with reference to four specific embodiments provided by way of nonlimiting examples and illustrated in the attached drawings, in which:

FIG. 1 is a three-dimensional view of a block according to a first embodiment of the invention;

FIG. 2 is a top view of an armor layer formed by blocks according to the first embodiment;

FIG. 3 is a three-dimensional view of a block according to a second embodiment of the invention;

FIG. 4 is a three-dimensional view of a block according to a third embodiment of the invention; and

FIG. 5 is a three-dimensional view of a block according to a fourth embodiment of the invention;

FIG. 1 shows a block 1 according to a first embodiment. In this embodiment, the block 1, made for example of concrete, has a central core 2 with a lower portion 3 and an upper portion 4, and a circular protuberance 5 arranged about the lower portion 3 of the central core 2.

The central core 2 has a lower base 6 (shown using a dotted line), an upper base 7 and lateral faces 8.

More specifically, the core 2 has two square bases 6, 7 forming the two main surfaces, which are preferably flat, that are joined by four lateral faces 8. The lateral faces 8 are free at the upper portion of same and covered by the circular protuberance 5 at the lower portion of same.

In the present case, the square bases, i.e. the bases 6 and 7, are considered to be identical and parallel. Furthermore, the lateral faces 8 are considered to be perpendicular to said bases 6, 7. Thus, the central core 2 of the block 1 is a square-based right prism.

The circular protuberance 5 has an octagonal lateral contour. In particular, the circular protuberance 5 has eight lateral faces 9. The octagonal contour of the circular protuberance 5 may be regular, i.e. have eight equal lateral faces 9, or irregular as shown in FIG. 1. In the latter case, the lateral faces 9 of the octagonal contour are identical pairs. More specifically, successive lateral faces of the circular protuberance 5 may have successive surfaces having two different values. Such an octagonal contour may in particular be obtained by chamfering the vertexes of the initial square contour. The lateral faces resulting from the edges of the square have the same surface area, which is greater than the surface area of the lateral faces formed by the chamfers. The lateral faces of the circular protuberance 5 then have equal pairs of surface areas.

The circular protuberance 5 may also have a circular surface 10 joining the lateral faces 9 of the circular protuberance 5 to the lateral faces 8 of the upper portion 4 of the central core 2. The circular surface 10 may thus have several faces 11 having angles from the horizontal of between 0° (in this case, the circular surface 10 is a shoulder) and 70°, for example between 5° and 65°.

In FIG. 1, the circular surface 10 has eight faces 11, each face 11 joining a lateral face 9 of the circular protuberance 5 to the upper portion 4 of the central core 2.

The lower portion of the circular protuberance 5 forms, with the lower base 6 of the central core 2, a preferably flat lower surface 12 of the block 1.

Advantageously, the lateral faces 9 of the circular protuberance 5 may be perpendicular to the bases 6, 7 of the central core 2. Alternatively, the lateral faces 9 of the circular protuberance 5 may be inclined, in the vicinity of the lower surface 12 of the block 1, towards the inside of the block in order to facilitate the flow of water between the blocks. In other words, the perimeter of the lateral contour of the circular protuberance 5 may diminish in the vicinity of the lower surface 12 of the block 1.

The height of the circular protuberance 5 constitutes 65% of the total height of the block 1, 50% of which corresponds to the lateral faces 9. The width, notably minimal, of the upper portion 4 of the central core 2 constitute 60% of the total width of the block 1. Each chamfer forming a lateral face 9 corresponds to the removal of 20% of the total width of the block 1.

FIG. 2 shows an armor layer 13 of a protective structure. The armor layer 13 comprises several blocks 1 (thirteen of which are shown in FIG. 2). The blocks 1 are arranged to butt up against one another. In particular, the lateral faces 9 of the circular protuberance 5 corresponding to the chamfers are arranged to butt up against the lateral faces 9 of the adjacent blocks. This makes it easy to arrange the different blocks 1 in the armor layer to obtain the desired spacing between the different blocks.

FIG. 3 shows a second embodiment of a protective block 1. The reference signs used in FIG. 3 are the same as those used for the first embodiment, and they refer to the same elements.

In FIG. 3, the circular surface 10 only has four faces 11, the lateral faces 9 of the circular protuberance 5 formed by the chamfers being taller than the other lateral faces.

FIG. 4 shows a third embodiment of a protective block 1. The reference signs used in FIG. 4 are the same as those used for the first embodiment, and they refer to the same elements.

In FIG. 4, the central core 2 has a lower base and an upper base 7 that are regular octagons. The upper portion 4 of the central core 2 therefore has eight identical lateral faces 8. Furthermore, the circular protuberance 5 also has a regular octagonal lateral contour, such that the upper portion 4 is a homothetic transformation of the circular protuberance 5. The inclined surface 10 also has eight identical faces 11.

According to this third embodiment, adjacent blocks 1 butt against the lateral faces 9. Since the eight lateral faces 9 of the circular protuberance 5 are identical, the blocks can be arranged more easily, with fewer orientation constraints.

FIG. 5 shows a fourth embodiment of a protective block 1. The reference signs used in FIG. 5 are the same as those used for the first embodiment, and they refer to the same elements.

In FIG. 5, the block 1 has a circular protuberance 5 with a square lateral contour. The circular protuberance 5 therefore has four identical lateral faces 9, and the vertexes of the lateral faces are not chamfered. However, the circular protuberance 5 has notches 14 to facilitate arrangement of the blocks together. The notches 14 are in the middle of the lateral faces 9. The notches 14 enable cooperation with the vertexes of the circular protuberance of the adjacent blocks, and form openings between the circular protuberances of adjacent blocks. In the case shown in FIG. 5, the notches 14 expose a fraction of the lower portion of the central core 2.

In each of the embodiments described above, the perimeter of the lateral contour of the circular protuberance 5 may diminish in the vicinity of the lower surface 12 of the block 1.

The circular protuberance may have vertical grooves on the lateral faces of same. Furthermore, the protective block 1 may also have at least one vertical through-hole and/or at least one horizontal through-hole to facilitate the flow of water in the armor layer.

A protective structure incorporating such an armor layer may also conventionally include a filter layer beneath the armor layer and a core carrying the filter layer and the armor layer and providing an overall shape to the assembly.

Claims

1. An armor layer of a protective structure for sea and/or river construction work comprising several protective blocks (1), each block having a central core (2) with an upper portion (4) and a lower portion (3), characterized in that the lower portion (3) of the central core (2) is surrounded by a circular protuberance (5) with lateral faces (9) and in that at least one of the lateral faces (9) can butt against at least one of the lateral faces of a circular protuberance of an adjacent block.

2. The armor layer as claimed in claim 1, characterized in that the circular protuberance (5) of each block can provide partial paving of a surface with adjacent protective blocks (1) in contact with one another via at least one of the adjacent faces of the circular protuberance (5).

3. The armor layer as claimed in claim 1, characterized in that the central core (2) of each block has a lower base (6) and an upper base (7), that are preferably flat, the lower base (6) and the upper base (7) being square or octagonal and joined by the lateral faces (8), and in that the circular protuberance (5) is arranged about the lower portion of the lateral faces (8) of the central core (2), from the lower base (6) of the central core (2).

4. The armor layer as claimed in claim 1, characterized in that the central core (2) of each block is a square- or octagonal-based right prism.

5. The armor layer as claimed in claim 1, characterized in that the circular protuberance (5) of each block includes an octagonal lateral contour or a square lateral contour having a notch (14) on at least one of the sides of same, the notch (14) being able to cooperate with a vertex of the square lateral contour of a circular protuberance of an adjacent block.

6. The armor layer as claimed in claim 5, characterized in that the octagonal lateral contour of the circular protuberance of each block corresponds to a square lateral contour in which the vertexes are chamfered.

7. The armor layer as claimed in claim 1, characterized in that the circular protuberance (5) of each block forms, with the lower base (6) of the core, a preferably flat lower surface (12) of the block (1).

8. The armor layer as claimed in claim 1, characterized in that the circular protuberance (5) of each block also has an inclined circular surface (10) joining the upper extremity of the lateral contour of the circular protuberance (5) to the lateral faces (8) of the central core (2).

9. The armor layer as claimed in claim 1, characterized in that the blocks (1) form partial paving covering between 60% and 90% of the surface on which the blocks are laid.

10. A protective block designed to be incorporated into an armor layer of a protective structure for sea and/or river construction work as claimed in claim 1.