Element and installation for stabilizing an underwater plot

Abstract

A stabilizing element for a plot that is at least partially underwater, at least at times, comprises a base (102) comprising several arms (103) angularly offset from each other around a central axis (X). Each arm (103) comprises a proximal portion (110) and an end (111) which extends this proximal portion (110). Notches (115) in the base (102) are located between the arms (103) and have a shape generally complementary to the ends (111) of the arms (103).

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to the field of combating coastal erosion, the effects of swell and other phenomena likely to act on, alter and / or modify seabeds and / or installations that are at least partially submerged permanently or at times, for example due to tides.

[0002] More specifically, the invention relates to a stabilizing element for a plot that is at least partially underwater at least at times, as well as an installation comprising several examples of this stabilizing element.

[0003] For example, the invention may be applied to the stabilization of a coastal beach, the stabilization of an underwater bottom such as a sandy bottom, the stabilization of a cliff foot and / or the stabilization of a seawall armour foot. STATE OF THE ART

[0004] Underwater dikes made of quarried stone blocks or geosynthetic tube systems, which are elongated bags filled with sand, have been proposed. Geosynthetic tubes are not a sustainable and therefore satisfactory solution, as they are very vulnerable due to their fragility to navigational incidents such as impacts from boats, boat anchors, and various floating objects.

[0005] The warming of the Earth's atmosphere is becoming increasingly a reality, with multiple consequences including rising sea and ocean levels and an increase in the frequency and severity of storms.

[0006] Such consequences of global warming on a terrestrial scale raise fears of a significant worsening of coastal erosion phenomena and changes in the nature and very functioning of these coastal erosion phenomena.

[0007] As a result, an old need is still relevant. This is the need to make progress in the fight against coastal erosion, the retreat of the coastline, the effects of swell and other phenomena likely to act on, alter and / or modify seabeds and / or installations that are at least partially submerged permanently or at times, for example due to tides. SUMMARY OF THE INVENTION

[0008] A patch of coastline that is alternately underwater and open air, with a repeating cycle of high tide and then low tide, is an example of a patch that is at least partially underwater at least at times. A seawall base is another example of a patch that is at least partially underwater at least at times.

[0009] A stabilizing element for a plot that is at least partially underwater at least at times comprises a base comprising several arms angularly offset from each other around a central axis. One end of each arm and notches in the base, between the arms, have generally complementary shapes, which allows neighboring stabilizing elements to be partially nested within each other. STATEMENT OF THE INVENTION

[0010] The invention aims at least to enable progress in the fight against coastal erosion, the effects of swell and other phenomena likely to act on, alter and / or modify seabeds and / or installations which are at least partially submerged permanently or at times, for example due to tides.

[0011] According to the invention, this aim is achieved by means of an element for stabilizing a plot that is at least partially underwater at least at times, which comprises a base comprising several arms angularly offset from each other around a central axis, each arm comprising a proximal part and an end which extends this proximal part, notches in the base being located between the arms and having a shape generally complementary to the ends of the arms.

[0012] By joining several examples of the stabilizing element according to the invention, it is possible to form a protective layer covering a plot to be stabilized. In this protective layer, two side-by-side examples of the stabilizing element may not be at exactly the same height and / or may not have the same inclination relative to the horizontal, depending on the topography of the plot to be stabilized, i.e. depending on possible spatial variations in relief at the level of this plot. The protective layer comprising stabilizing elements according to the invention is thus adaptable to possible spatial variations in relief in the plot to be stabilized.As if it were formed of scales articulated to each other, this protective layer is also adaptable to possible changes over time in the relief of the plot to be stabilized, compared to a concrete screed under which a hollow can form and grow over time.

[0013] Compared to conventional rockfill and known geosynthetic tubes, the invention allows a different arrangement and a different mode of action. The known rockfill and geosynthetic tube solutions are effective and / or possible in certain specific areas of use such as the reinforcement of dikes or the construction of breakwaters. The inventors of the present invention have found that it is possible to combat coastal erosion, the effects of swell and other phenomena capable of acting on, altering and / or modifying seabeds and / or installations that are at least partially submerged permanently or at times, for example due to tides, in a different and / or different way.

[0014] Due to the generally complementary notches at the end of each arm, two adjacent stabilizing elements according to the invention can be partially fitted into each other.

[0015] In embodiments, the stabilizing member includes a central portion to which the arms connect.

[0016] In embodiments, the central portion includes a protruding portion that projects upwardly relative to the arms.

[0017] A grouping of such upwardly projecting protruding portions effectively breaks waves and / or effectively slows currents in water. It can act in the manner of a reef, for example a coral reef, and promote the development of fauna and flora, and the settlement of certain aquatic life, in particular marine life, including for example sedentary algae, shells, crustaceans, starfish, sea anemones, fish, etc. Underwater dikes made of geosynthetic tubes of the prior art or quarried stone blocks act little or practically not in the manner of a reef promoting the development and settlement of certain aquatic life, in particular marine life.

[0018] In embodiments, the base comprises at least a portion of the central portion.

[0019] Thanks to these provisions, the base can cover a large area of ​​the plot to be stabilized.

[0020] In embodiments, the stabilizing element includes a central void space surrounded by the central portion.

[0021] Thanks to these provisions, the stabilizing element can be made lighter, which is advantageous for its transport and / or handling. In addition, less raw material can be used for its manufacture.

[0022] In embodiments, the protruding portion includes lateral conduits communicating the central void space with the exterior.

[0023] Thanks to these provisions, aquatic fauna can use such lateral conduits to enter and / or exit the central empty space used as a refuge.

[0024] In embodiments, the central void space opens upwardly into the top of the central portion.

[0025] Thanks to these arrangements, daylight can illuminate the central empty space used by aquatic fauna as a refuge.

[0026] In embodiments, the central void space opens downwardly into the underside of the base.

[0027] In embodiments, the central void space is a rising passageway that passes through by opening upwards into the top of the central portion and by opening downwards into the bottom of the base.

[0028] By virtue of these provisions, when the stabilizing element is lowered or lowers under its own weight into water, water can pass into the central void space, rather than braking and / or tipping the stabilizing element. In addition, daylight can illuminate the central void space used by marine wildlife as a refuge.

[0029] In embodiments, the rising passage has a lower end, a portion higher than the center of gravity of the stabilizing element, and a passage section larger at its lower end than at its portion higher than the center of gravity of the stabilizing element.

[0030] Thanks to these arrangements, when the stabilizing element 1 is lowered or descends under the effect of its own weight into water, water is caused to rush into the central empty space, through the lower end thereof, and to form a current passing through the stabilizing element, which tends to oppose a significant tilting or even a turning over of the stabilizing element.

[0031] In embodiments, the tip of each of the arms includes an edge having two sides that form a projecting angle between them pointing in the direction opposite the central portion.

[0032] Thanks to these provisions, the end has an edge capable of guiding its fitting into a complementary notch.

[0033] In embodiments, there are five arms.

[0034] Thanks to these arrangements, several copies of the stabilizing element can be arranged relative to each other on an underwater bed or other surface, in a regular and optimal manner.

[0035] By means of these arrangements, several copies of the stabilizing element can be arranged relative to each other in a regular and optimal manner, leaving little exposed surface between them, for example on a seabed or another submerged surface subject to erosion.

[0036] In embodiments, the arms are regularly distributed around the central axis.

[0037] In embodiments, the stabilizing element comprises a ground anchoring relief, this anchoring relief equipping the underside of the base.

[0038] Thanks to these provisions, the stabilizing element remains better in its place once installed.

[0039] In embodiments, the anchor relief comprises downwardly projecting pyramids.

[0040] In embodiments, the stabilizing element includes a molded portion that includes or defines the arms. In a first example, this molded portion is made of cast concrete. In a second example, the molded portion is a polymer shell. In embodiments, the stabilizing element is made of at least one material, which is concrete or a similar material.

[0041] The invention also relates to an installation for stabilizing a plot that is at least partially underwater at least at times, which comprises several stabilizing elements as defined above, the bases of the first and second stabilizing elements side by side among the stabilizing elements resting on the underwater plot, one end of one of the arms of the first stabilizing element being generally fitted into one of the notches of the second stabilizing element. BRIEF DESCRIPTION OF THE FIGURES

[0042] Other advantages and characteristics will emerge more clearly from the following description of a particular embodiment of the invention, given by way of non-limiting example and represented in the appended drawings, among which: There figure 1 is a perspective view of a stabilizing element according to one embodiment of the invention, in place on an underwater bed, The figure 2 is a top view of the stabilizing element visible on the figure 1 , There figure 3 is a bottom view of the stabilizing element visible on the figures 1 And 2 , There figure 4 is seen in axial section of the stabilizing element visible on the figures 1 à 3 , There figure 5 is side view on which the stabilizing element visible on the figures 1 à 4 is submerged and remains on an underwater bed, and The figure 6 is a schematic view, from above, on which a permanent stabilization installation on an underwater bed comprises a grouping of several attached copies of the stabilization element of the figures 1 à 5 . DESCRIPTION OF THE EMBODIMENTS

[0043] On the figure 1 , a stabilizing element 101 according to an embodiment of the invention rests on an underwater bed F to be stabilized, such as an underwater expanse of sand subject to intermittent sea currents.

[0044] A base 102 of the stabilizing element 101 comprises several generally identical arms 103, which connect to a central portion 104.

[0045] When the stabilizing element 101 is in place for example on an underwater bed F to be stabilized, its base 102 including the arms 103 rests on this underwater bed F, which is the case on the figure 1 .

[0046] In the following and in the appended claims, the terms "bottom", "top", "below", "above" and "side", as well as analogous terms, consider that the stabilizing element 101 is definitively installed and operational at its final destination location and that its base 102 rests on a substantially horizontal surface such as the seabed F. Of course, according to another possible use situation, the permanent stabilizing element 1 rests on an irregular and / or inclined surface of a plot to be stabilized.

[0047] The central portion 104 comprises a projecting portion 105, which projects upwards, relative to the arms 103.

[0048] The arms 103 are arranged in a star shape and angularly offset from each other around a central axis X.

[0049] As one can well see on the figures 2 et 3 , the arms 103 are radial arms, each of which extends along a radial axis R perpendicular to the central axis X.

[0050] The arms 103 are regularly distributed around the central axis X. In other words, the angle between the two arms 103 of a pair of consecutive arms 103 is generally the same, regardless of the considered pair of consecutive arms 103. The angle α between two consecutive arms 103 of any pair of consecutive arms 103 is generally equal to 360° divided by the number n of arms 103.

[0051] In the embodiment shown, the number n of arms 103 is five, and the angle α between two consecutive arms 103 of any pair of consecutive arms 103 is generally equal to 72°.

[0052] In the embodiment shown, the arms 103 are five in number and have the same length. According to a first alternative embodiment, the number n of arms 103 may be other than five. According to a second alternative embodiment, the arms 103 have different lengths from each other. According to a third alternative embodiment, the number n of arms 103 is other than five and the arms 103 have different lengths from each other.

[0053] Each arm 103 has a proximal portion 110 which connects to the central portion 104. Each arm 103 has a tip 111 which extends its proximal portion 110. Each tip 111 has an edge 112 having two sides 113 which form between them a salient angle pointing in the direction opposite to the central portion 104.

[0054] The base 102 comprises notches 115 that are identical to each other. Each notch 115 is located between two consecutive arms 103 that delimit it. Each notch 115 has a shape that is generally complementary to any end 111. Each notch 115 comprises an edge 116 having two sides 117 that form a re-entrant angle between them pointing towards the central portion 104. Each side 117 has generally the same length as each side 113.

[0055] As can be seen on the figures 3 And 4 , the underside 118 of the base 102 is provided with pyramids 119 which project downwards. The pyramids 119 form an anchoring relief of the stabilizing element 1 in the underwater bed F.

[0056] As we can clearly see on the figure 4 , the central portion 104 is hollow and crossed from one side to the other by a central empty space 120. This central empty passage 120 has the form of a rising passage which opens upwards, into the top of the projecting portion 105, and which opens downwards, into the bottom 118 of the base 102.

[0057] The central empty space 120 is flared so that its passage section decreases as one ascends. The passage section of the central empty space 120 is thus greater at the lower end thereof than at an upper part that this central empty space 120 comprises above the center of gravity G of the stabilizing element 1. When the stabilizing element 1 is lowered or descends under the effect of its own weight in water to the plot to be stabilized, water is thus caused to rush into the central empty space 120, through the lower end thereof, and to form a current passing through the stabilizing element 1, which tends to oppose a significant tilting or even a turning over of the stabilizing element 1.

[0058] The projecting portion 105 comprises lateral conduits 125 connecting the central empty space 120 with the space outside the stabilizing element 101.

[0059] When the stabilizing element 101 in place on the seabed F is submerged, the central empty space 120 filled with water forms a refuge for underwater fauna. This underwater fauna can use the lateral conduits 125 to enter and exit the central empty space 120.

[0060] On the figure 5 , the stabilizing element 101 is in place on the seabed F. Its base 102 covers a portion of this seabed F and thus protects this portion against the various currents which can occur in the seawater E. In the case where the stabilizing element 101 is only partly submerged, its base 102 also protects the covered portion against waves.

[0061] The stabilizing element 101 is made of concrete. This concrete is unreinforced or it is reinforced for example by fibers such as glass fibers, carbon fibers, polymer fibers and / or by other reinforcements that are chosen from those that do not swell in the presence of chlorides if the stabilizing element 1 is intended for a marine or oceanic environment.

[0062] According to a variant, the stabilizing element 101 comprises an envelope such as a shell or a lost formwork, this envelope containing concrete molded therein and / or one or more granular materials such as sand, gravel, stones, pebbles and / or a mixture of several of them.

[0063] Preferably, the stabilizing element 101 is manufactured at or near the location of the plot of land it will be used to stabilize. This avoids the need to transport large and heavy elements over long distances, which is not the case most of the time when building an underwater dike from quarried stone blocks.

[0064] On the figure 3 , an installation 130 for stabilizing a larger portion of the seabed F comprises two adjoining rows of stabilizing elements 101 themselves adjoining, which rest on this seabed F.

[0065] In each row, it is repeated that one end 111 of one of two consecutive stabilizing elements 101 is fitted into a notch 115 of the other stabilizing element 101 among these two consecutive stabilizing elements 101. In addition, one end 111 of each stabilizing element 101 of the row on the right on the figure 6 is fitted into a notch 115 of a stabilizing element 101 of the row on the left on the figure 6 .

[0066] Thanks to the end fittings 111 in notches 115, the stabilizing elements 101 of the stabilizing installation 130 lock each other against pivoting on themselves, while blocking each other in horizontal translation.

[0067] On the figure 6 , the stabilization installation 130 only comprises five stabilization elements 101 for the sake of clarity.

[0068] As can be seen on the figure 6, the majority of the plot where the stabilization installation 130 is located is covered by the stabilization elements 1. There are certainly uncovered areas 140 between the stabilization elements 101. However, these uncovered areas 140 are few in number and each have a small surface area. It is very difficult for a water current, or for breaking wave eddies, to reach them due to their small size and their depth relative to the tops of the arms 103. In addition, and depending on the nature of the supporting soil, an anti-scour mat can be laid beforehand, avoiding losses of supporting soil.

[0069] Two consecutive stabilization elements 1 of the stabilization installation 130 may not be at exactly the same height and / or may not have the same inclination relative to the horizontal, depending on the topography of the plot to be stabilized, that is to say depending on possible spatial variations in relief at the level of this plot. The stabilization installation 130 forms a protective shell which is thus adaptable to possible spatial variations in relief in the plot to be stabilized. As if it were formed of scales articulated to each other, this protective shell is also adaptable to possible changes over time in possible spatial variations in relief in the plot to be stabilized, compared to a concrete screed under which a hollow can form and expand over time.

[0070] The projecting portions 105 in the stabilization installation 130 act collectively against possible waves, which they effectively break. The projecting portions 105 in the stabilization installation 130 provide mutual protection of the stabilization elements 101 in the installation 130 against waves, in a manner comparable to the mutual protection that trees in a forest provide against winds. The projecting portions 105 in the stabilization installation 130 act collectively against water currents, which they effectively slow down. The projecting portions 105 in the stabilization installation 130 provide mutual protection of the stabilization elements 101 in the installation 130 against water currents, in a manner comparable to the mutual protection that trees in a forest provide against winds.

[0071] The protruding portions 105 in the stabilization facility 130 form a kind of reef in which marine fauna can develop. For example, in the stabilization facility 130, marine fauna can wander freely between the central empty spaces 120.

[0072] According to a first example of use, the stabilization installation 130 covers and stabilizes a sandy bottom. According to a second example of use, the stabilization installation 130 covers and stabilizes a beach or other coastal area. According to a third example of use, the stabilization installation 130 covers and stabilizes the toe of an armour of a seawall.

[0073] According to other examples of use, the stabilization installation 130 is installed in fresh water, for example at the banks of a river or stream.

Claims

1. Stabilization element of a plot at least partially underwater at least at times, characterized in thatit comprises a base (102) comprising several arms (103) angularly offset from each other around a central axis (X), each arm (103) comprising a proximal part (110) and an end (111) which extends this proximal part (110), notches (115) in the base (102) located between the arms (103) and having a shape generally complementary to the ends (111) of the arms (103), a central portion (104) to which the arms (103) connect, a central empty space (120) surrounded by the central portion (104), the central empty space (120) being a rising passage which is traversing by opening upwards, in the top of the central portion (104), and by opening downwards, in the bottom (118) of the base (102), the rising passage having a lower end,a part higher than the center of gravity (G) of the stabilizing element and a larger passage section at its lower end than at its part higher than the center of gravity (G) of the stabilizing element., 2. Stabilizing element according to claim 1, in which the central portion (104) comprises a projecting portion (105) which projects upwards, relative to the arms (103).

3. Stabilizing element according to claim 2, in which the projecting portion (105) comprises lateral conduits (125) putting the central empty space (120) into communication with the exterior.

4. Stabilizing element according to one of claims 1 to 3, in which the end (111) of each of the arms (103) comprises an edge (112) having two sides (113) which form between them a projecting angle pointing in the direction opposite to the central portion (104).

5. Stabilizing element according to one of claims 1 to 4, in which the arms (103) are five in number.

6. Stabilizing element according to one of claims 1 to 5, which comprises a relief (119) for anchoring to a ground, this anchoring relief (119) equipping the underside of the base (102).

7. Installation for stabilizing a plot that is at least partially underwater at least at times, characterized in that it comprises several stabilizing elements (101) according to one of claims 1 to 6, the bases (102) of first and second stabilizing elements (101) side by side among the stabilizing elements (101) resting on the underwater plot, an end (111) of one of the arms (103) of the first stabilizing element (101) being generally fitted into one of the notches (115) of the second stabilizing element (101).

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