FR3068676A1 - DEAD BODY MODULE FOR ANCHORING A FLOATING STRUCTURE - Google Patents

Abstract

Module for dead body intended to be immersed and to carry out the anchoring of a floating structure, the module (24) comprising: - a hollow cylindrical drum (26), and - two closing elements (28, 30) adapted to respectively closing opposite ends of the barrel, the barrel and the shutter elements being precast concrete, the module being intended to be mechanically secured to at least one other module of the dead body to form said dead body.

Description

Dead body module for anchoring a floating structure

The field of the invention relates to the anchoring of floating structures, and in particular to the dead bodies used for this purpose.

Several approaches are used for anchoring floating structures, such as, for example, oil exploitation structures or even electrical energy production of the wind type.

One of these approaches is based on the use of cables fixed to a seabed by means of one or more suction anchors fixed to this seabed. These suction anchors are typically in the form of a cylindrical tube anchored by friction in the seabed and whose installation is done by applying vacuum between the ground and the inside of a bell delimited in the upper part of the tube through the ceiling of it.

In certain configurations, in particular when it is necessary that the average vertical level of the anchored structure does not vary as a function of the level of the swell, retaining cables are used stretched between the anchoring point situated at the level of the seabed and the floating structure.

In this type of configuration of use, it sometimes happens that it is not possible to use the approach of anchoring by suction above, or that such an approach is very expensive.

It is then known to use a dead body arranged at the seabed as an anchor of the floating structure, which then remains fixed under the effect of its weight for the vertical part of the retaining forces, under the effect of the forces of friction and abutment on the seabed for the horizontal part of these retaining efforts.

Due to the efforts involved, in order to remain fixed without being attached to the seabed, such dead bodies are generally massive structures, which have a generally complex design and a high cost.

The invention aims to improve the situation.

To this end, the invention relates to a module for dead body intended to be submerged and to anchor a floating structure, the module comprising:

- a hollow cylindrical barrel, and

- two closure elements adapted to respectively seal opposite ends of the barrel, the barrel and the closure elements being of precast concrete, the module being intended to be mechanically integral with at least one other module of the dead body to form said dead body.

According to one aspect of the invention, the module further comprises at least one prestressing element extending in the wall of the barrel and having ends respectively anchored in one and the other of the obturation elements.

According to one aspect of the invention, at least one obturation element has at least one interface region intended to be fixed to said other module for the formation of the dead body.

According to one aspect of the invention, at least one closure element has a polygonal outline.

According to one aspect of the invention, the interface region corresponds to one of the slices of the polygonal outline of the at least one obturation element.

According to one aspect of the invention, the barrel comprises a plurality of superimposed barrel segments.

According to one aspect of the invention, each obturation element receives at least one prestressing element arranged in the thickness of the obturation element substantially parallel to a plane of the obturation element.

According to one aspect of the invention, the module comprises a ballasting device suitable for the controlled filling of the barrel with water.

According to one aspect of the invention, the module comprises a pressurization device suitable for regulating a pressure prevailing in an interior volume delimited by the barrel by injection of gas into the interior volume.

According to one aspect of the invention, the closure elements are in the form of tiles of general configuration of a flat plate.

The invention further relates to a dead body configured for anchoring a floating structure, the dead body being intended to be immersed, the dead body comprising a plurality of modules according to any one of the preceding claims mechanically secured to each other.

According to one aspect of the invention, two adjacent modules are mechanically secured to one another by fixing at least one of the closure elements of one of the two adjacent modules with at least one of the shutter elements of the other of the two adjacent modules.

According to one aspect of the invention, sections of two respective closure elements of two adjacent modules are fixed to each other at least by a joint.

According to one aspect of the invention, the dead body comprises at least one prestressing element received simultaneously in the respective closure elements of a plurality of said modules and exerting a force maintaining the closure elements of the corresponding modules secured to each other other.

According to one aspect of the invention, at least one prestressing element received in the closure elements crosses said joint.

The invention further relates to a method of building a dead body for anchoring a floating structure, the method comprising:

- prefabricate, from concrete, hollow cylindrical drums and respective closure elements of a plurality of modules each comprising a barrel and two closure elements respectively closing opposite ends of the barrel,

- from the drums and obturation elements, form an assembly mechanically secured to a plurality of said modules to form the dead body, and

- arrange the dead body on a seabed.

According to one aspect of the invention, arranging the dead body on a seabed comprises regulating the pressure in a barrel volume of at least part of the modules during the descent of the dead body to the seabed by injection of gas into the barrels in order to maintain a level of flexion of the sealing elements of the corresponding modules below a predetermined level.

According to one aspect of the invention, the drums of the dead body modules are at least partially filled with water for their placement on the seabed.

According to one aspect of the invention, the method further comprises removing the dead body from the seabed, said removal comprising at least partial emptying of the barrel of all or part of the water modules which the barrel contains to increase the buoyancy corresponding modules.

The invention will be better understood on reading the detailed description which follows, given solely by way of example and made with reference to the appended Figures, in which:

Figure 1 illustrates a floating structure anchored by means of a dead body according to the invention; Figures 2a to 2c illustrate different views of a module of a dead body according to the invention; Figure 3 illustrates a sectional view of a part of a dead body according to the invention;

Figure 4 illustrates an assembly of modules to form a dead body according to the invention; Figures 5a to 5f illustrate different configurations of dead body according to the invention;

Figure 6 illustrates the steps of a process for building a dead body according to the invention.

Figure 1 illustrates a floating structure 10 anchored to the seabed 11 by means of at least one dead body 12 according to the invention arranged at the seabed 11. The anchoring is carried out via retaining cables 14 extending between the floating structure 10 and the dead bodies 12.

In the context of the invention, advantageously, the floating structure 10 is an installation for producing electrical energy from the wind.

The floating structure 10 comprises a floating base 16, and a wind turbine 18 fixed to the base 16.

The base 16 is for example of known invoice. For example, it is formed from a plurality of reinforcements connected together. The base 16 is for example immersed, as illustrated in Figure 1.

The wind turbine 18 comprises a mast 20 fixed on the base 16, and a nacelle 22 supported by the mast 20 and comprising a rotor provided with blades for the generation of electricity by rotation of the blades under the effect of the wind.

It is noted that although such a wind structure is a context of privileged use of the invention, the invention applies to any type of floating structure 10.

The retaining cables 14 are for example of known invoice. The retaining cables 14 each extend between the structure 10 and a dead body 12.

Advantageously, in the context of the invention, the retaining cables 14 are stretched between the base 16 of the structure 10 and the corresponding dead body 12, and this advantageously so as to contain the variations in the vertical level of the structure 10 at swell at a predetermined range. This range is for example chosen as forming an acceptable range for one or more constraints applying to the floating structure 10.

Each dead body 12 is intended to be immersed. Each dead body 12 is configured to form a stationary anchorage of the floating structure 10 to the seabed 11. More specifically, each dead body 12 is configured to remain stationary under the effect of its weight and the friction and the abutment which exert between the dead body 12 and the seabed 11. In other words, each dead body 12 is simply placed on the seabed and remains fixed in particular because of its dimensioned weight to mobilize friction and abutment forces between the dead body 12 and the seabed 11 preventing the displacement of the dead body under the effect of the forces of the floating structure 10 taken up by the dead body 12.

Each dead body 12 includes a plurality of modules, or boxes, 24 according to the invention.

The modules 24 of a dead body 12 are mechanically secured to each other. The modules 24 are thus integral in movement, all of them being displaced in the event of displacement of the dead body 12.

The modules 24 of a given dead body 12 jointly form the main element of the dead body

12, the dead body 12 being essentially defined as a monolithic assembly of the modules 24 which it comprises.

With reference to Figures 2a and 2b, each module 24 comprises a barrel 26 and two shutter elements 28, 30 configured to close the ends of the barrel 26.

In the context of the invention, the barrel and the closure elements 28, 30 are precast concrete elements.

The concrete used for their production is qualified for underwater use.

The barrel 26 is cylindrical and hollow, and internally delimits a volume 32.

The barrel 26 is closed at each of its ends by one of the closing elements 28, 30. The closing element located lower relative to the barrel according to the orientation of the Figures bears the reference 28, and forms the element said bottom shutter 28, and the shutter element 30 forms the so-called top reference shutter element 30.

Advantageously, the cylindrical shape of the barrel 26 is straight.

In addition, advantageously, in this configuration, the barrel 26 is of circular section. This arrangement is advantageous because it offers good resistance to the surrounding hydrostatic pressure during the immersion of the module. However, this circularity is optional, the section can be arbitrary. Advantageously, this section is convex. In a given configuration, this section is polygonal.

Preferably, in the context of the invention, the barrel 26 comprises one or more conduits 34 arranged in the wall of the barrel 26 each receiving at least one element, or armature, of prestressing 36. The conduits 34 extend from one end longitudinal to another of the bole 26.

The conduits 34 are for example regularly distributed around the longitudinal axis of the barrel 26.

Advantageously, the conduits 34 are straight. The conduits 34 extend parallel to the longitudinal axis of the barrel 26.

Alternatively, the conduits 34 are formed of rectilinear portions parallel to each other and to the axis of the barrel. These portions are for example spatially offset and / or not parallel to each other. For example, in such a configuration, they are joined two by two by a connection portion.

The prestressing elements 36 are configured to compress the drum 26 longitudinally.

Advantageously, they are also configured to contribute at least partially to secure the barrel 26 and the obturation elements 28, 30.

The prestressing element or elements 36 are for example cables or bars. Note that the cables have any structure, for example single strand or multiple strands, these strands being or not strands.

Each prestressing element 36 is advantageously anchored in the closure elements 28, 30 at its ends. Due to this configuration, the elements 36 tend to bring the elements 28, 30 closer to the barrel and thus contribute to securing the elements of the module 24 considered.

To this end, each closure element comprises, for each conduit 34, a passage portion 35 which extends the corresponding conduit 34 and an anchoring region 37 into which the passage portion 35 opens. This anchoring region 37 is for example arranged at an external face of the closure elements and comprises for example a recess arranged in this face itself.

Advantageously, each duct 34 receives a sheath in which the corresponding preload element (s) 36 is received. This sheath is for example embedded in the concrete of the barrel 26 at the time of the manufacture of the barrel to form the conduit 34.

Advantageously, each conduit 34 is injected with a material after tensioning of the elements 36 to fill the voids between them and the walls of the conduit 34 (of the sheath if necessary).

The material in question is configured to constitute a protective barrier against corrosion.

In a first configuration, the material is configured to adhere the element or elements 36 received in the conduit 34 and the walls of the conduit 34. This allows a lasting transfer of the prestressing forces resulting from the presence of the elements 36 in the barrel.

For example, the material is a cement grout.

In another configuration, each prestressing element is coated with a corrosion protection material and individually sheathed. In the latter case, the prestressing elements transfer their forces to the barrel essentially by their end anchorages. In particular, the prestressing elements 36 are then not designed to adhere to the walls of the duct 34.

Advantageously, the barrel 26 includes a plurality of segments 38 superimposed to form the barrel 26, as illustrated in Figures 2a and 2b.

Each segment 38 has a general cylindrical configuration of the same section as the barrel 36 relative to the longitudinal axis of the barrel.

In other words, each segment corresponds to a vertical portion of the barrel, as illustrated in the Figures.

In the embodiments with conduits 34, each segment 38 includes, for each conduit 34, a portion of the conduit considered.

In these embodiments, the prestressing elements 36 contribute to securing the segments 38 to each other due to the longitudinal compression of the barrel that they exert.

Regarding the dimensions of the modules, the barrel 26 has a diameter (or transverse characteristic dimension relative to its longitudinal axis in general) between 5 m and 20 m

For example, module 24 has a height of between 5 m and 20 m.

In addition, the thickness of the barrel walls is for example between 0.1 m and 1.0 m.

Advantageously, the dimensions of the modules are chosen as a function of the ratio between the weight and the internal volume of the modules 24 on the one hand, and of the ratio between the width and the height of the modules on the other hand.

The first of these reports is characteristic of the buoyancy of the modules. The second report is characteristic of the stability of the dead body 12, in particular in terms of overturning. We ideally seek to obtain a good compromise between these constraints.

Advantageously, the ratio between the diameter of the barrel 26 and the height of the module 24 is close to the unit. An optimal thickness of the barrel walls and the thickness of the obturation elements can easily be deduced from the diameter and / or the height chosen.

Note that the respective dimensions of the different modules of a dead body 12 are for example taken substantially identical.

Still with reference to Liguria 2a and 2b, as indicated above, the obturation elements 28, 30 close off the barrel 26. They respectively form a bottom and a cover of the barrel 26.

In the context of the invention, advantageously, the closure elements are in the form of slabs. By "slab" is meant a block of material of general configuration of a flat plate.

In this configuration, the shutter elements are preferably parallel to each other.

Each closure element 28, 30 comprises a first portion PI and a second portion P2.

These two portions are preferably formed from one another.

The first portion Pl confers to the obturation element corresponding to its general appearance.

For slabs, the first PI portion is in the form of a flat plate, one side facing away from the barrel and the opposite side facing the barrel.

This PI portion is advantageously orthogonal to Barrel Tax 26.

The periphery of the portion PI projects radially with respect to the second portion P2 and to the barrel 26.

The first portion PI, and the corresponding generally closing element, has a contour C. This contour C is configured to give the module 24 a radial overhang relative to the barrel.

Advantageously, within the framework of the invention, this contour C is polygonal. For example, it is hexagonal or octagonal.

The detail of the configuration of the contour C is chosen as a function of the configuration of the corresponding dead body 12 and of the chosen relative arrangement of the modules 24, as described below.

In general, the contour C has slices T. These slices are turned away from the module 24. These slices are advantageously vertical. In other words, a vector normal to these slices is orthogonal to Tax of the barrel 26.

Each section T has at least one section which is diametrically opposite to it. Two diametrically opposite sections are advantageously parallel to one another.

At least one of the edges of the outline C forms an interface region intended to be attached to a edge of the outline C of a module 24 adjacent within the dead body 12 to define the dead body in question. This is described in more detail below.

Each slice T advantageously has a generally rectangular shape. Advantageously, each section has a generally planar configuration. It is noted however that one or more slices may include, in a region, a portion of a shear key defined by this portion and a portion of complementary shape carried by a slice intended to be secured to this slice.

This is for example the case for the lower obturation elements 28.

Advantageously, the different sections T of the different lower and / or upper closure elements of the different modules 24 are of substantially identical sizes. In other words, the edges T of the contours of the elements 30 advantageously have the same size. In addition, it is advantageously the same for the sections of the elements 28.

Advantageously, the shutter elements 28, 30 have respective contours of identical shape. The respective dimensions, in particular radial, of these contours may however be different.

In addition, their relative orientation is configured so that the respective contours C of the closure elements 28, 30 of a given module 24 are not pivoted relative to one another.

In other words, in the assembled configuration of a module, advantageously, the shutter elements 28, 30 have homothetic contours.

Advantageously, the lower closure element 28 has dimensions slightly greater than those of the upper closure element 30. This allows the presence of a joint of dimensions chosen between one or more of the edges of the contour of the element. upper shutter with one or more of the neighboring modules 24, as described below.

For example, the projection between the closure elements 28 and 30 is approximately 10 cm, so as to provide a width of 20 cm for pouring in place the joints between the upper closure elements 30 of neighboring modules.

As for the second portion P2 of each obturation element projecting from the face of the first portion PI facing towards the barrel 26.

The second portion P2 includes a flange 40 configured to bear against the upper face of the barrel 26 on the circumference thereof.

In certain embodiments, the second portion P2 is formed by this rim 40. In other words, it does not include anything else.

However, alternatively, the second portion P2 comprises a central region 42 extending internally relative to the rim 40. This region is advantageously separated from the rim 40 by a shoulder 44 so as to have an outer edge of dimensions complementary to the barrel. This central region thus extends into the interior volume 32 when the obturation element closes the barrel.

In this configuration, this central region 42 prevents any relative sliding of the barrel 26 and of the obturation element.

It is noted that optionally, the face of the central region 42 facing the opposite closure element of the module 24 has a depressed and non-planar configuration over all or part of its surface.

Note that the second portion P2 is optional. In certain configurations, the shutter element 28, 30 considered is formed by its only PI portion.

Referring to Figure 2c, advantageously, each closure element 28, 30 includes at least one conduit 46 for the reception of an element, or armature, of prestressing 48 in the thickness of the element 28, 30 in question . Each duct 46 is advantageously arranged parallel to a plane of the closure element 28, 30, and more specifically to the plane of the first portion PI. For example, the conduits 46 are arranged precisely in the first portion PI.

Advantageously, each duct 46 joins a slice of the contour C of the shutter element to the slice T of the opposite contour C. Advantageously, each conduit 46 is then substantially perpendicular to the sections which it joins to one another.

Advantageously, each conduit 46 is rectilinear.

However, as a variant, the duct 46 comprises a plurality of rectilinear and parallel sections which are joined together by any connection portions.

Advantageously, at least one pair of opposite edges T of the contour C of a closure element 28, 30 is associated with at least one conduit 46.

It is noted that the conduits 46 can be arranged in several parallel planes in the thickness of the shutter element according to their number.

Each prestressing element 48 is received in one of the conduits 46 and is configured to exert a compression force at least on the corresponding obturation element.

In the context of the invention, advantageously, at least one prestressing element 48 is received simultaneously in respective closure elements 28, 30 of a plurality of modules 24 and exerts a force tending to maintain the corresponding closure elements and therefore the modules considered integral with each other. In other words, with reference to FIG. 2c, the dotted portion of the element 48 is received in a conduit 46 of a closure element of at least one module 24 adjacent to the dead body 12 and tends to bring the modules closer together. 24 illustrated in question towards each other. Advantageously, all of the prestressing elements 48 have this configuration.

Note that an element 48 is received only in lower obturation elements 28, or only in upper obturation elements 30.

Each prestressing element 48 advantageously crosses the respective closure elements of the set of neighboring modules 24 which are in its path. In other words, as illustrated in FIG. 5f which illustrates elements 48 each traversing three slabs, if the dead body 12 comprises N modules 24 juxtaposed along a given direction, each prestressing element 48 extending parallel to this direction is received in the shutter elements of these N modules. Thus, a prestressing element 48 alone contributes to the monolithic nature of the dead body 12.

Each prestressing element 48 is advantageously anchored at its ends (points A1 and A2 in FIG. 2c) at the level of the edges T of the obturation elements of the end modules that it passes through. The anchoring of these elements 48 is for example carried out in a known manner, for example at the level of a region 47 (FIG. 4) formed in the section T considered and having a configuration similar to the anchoring region 37.

The prestressing elements 48 are for example bars or cables.

It should be noted that advantageously, the conduits 46 each receive, for example, a sheath which itself receives the prestressing element or elements 48. This sheath is embedded in the concrete constituting the closure element, for example during the manufacture of this element.

The conduits (the sheaths if applicable) are advantageously filled with a protective material after tensioning of the elements 48, as for the conduits 36.

As indicated previously, the barrel 26 and the shutter elements 28, 30 of a given module 24 are made integral at least by the prestressing elements 36.

Alternatively or in parallel, the barrel 26 and the shutter elements 28, 30 of a given module 24 are also made integral by interface seals 39 between these elements.

The interface seals 39 are for example made from epoxy glue.

It is noted that such seals are also present at the interfaces between the segments 38 of the drums in the corresponding embodiments.

Advantageously, the interfaces between the barrel 26 and the slabs 28, 30 are each provided with at least one shear key (not shown) configured to ensure the correct relative positioning of these elements and to prevent relative slippage of the elements considered.

At least one of these keys comprises for example a tenon and a mortise respectively carried by one and the other of the elements defining the interface considered, and configured to cooperate with each other to immobilize relatively the one and the other of these elements.

Also optionally, at least one interface between a closure element 28, 30 and the barrel 26 includes a sealing element 49 (Figure 2c). The sealing element defines a seal of the module 24. It is for example in the form of a ring of deformable material intended to be compressed between the two elements defining the interface in question to seal the latter ( slab 30 and was 26 in Figure 2c). Advantageously, it is received in a groove from which it projects.

In addition to the barrel 26 and the closure elements 28, 30, at least one module 24 optionally comprises a device 50 adapted for the controlled filling of the barrel 26, that is to say of the interior volume 32, with water. Advantageously, the device 50 is also suitable for the emptying of water from the volume 32.

The device 50 is for example carried by one of the shutter elements 28, 30, advantageously by the lower shutter element 28, or even by the barrel 26, for example in the lower part.

The device 50 advantageously includes one or more valves. In the configurations in which the device 50 is adapted to drain the volume 32, the device 50 advantageously comprises a hydraulic pump arranged to discharge the water from the volume 32 outside this volume 32.

Advantageously, for at least certain modules 24 of a dead body 12, the respective devices 50 of these modules are suitable for the communication of the interior volumes 32 corresponding to each other for balancing the water content of the volumes 32, that is i.e. the height reached by water in volumes 32.

Advantageously, for this purpose, the corresponding devices 50 include one or more communication channels 51 (FIG. 3), advantageously inserted in the lower obturation elements 28 of the modules 24 considered, to put the volumes 32 into communication with each other. In one configuration, these channels connect the drums 26 considered together.

Optionally, at least one module 24 comprises a device 52 suitable for the insertion into the volume 32 of solid ballasting or ballasting elements.

These elements are intended to increase the dry mass of the modules 24 and of the dead body 12.

Advantageously, these ballast elements comprise aggregates or metallic elements, such as for example by-products from the steel industry.

The device 52 is for example carried (in whole or in part) by the upper shutter element 30.

Preferably, the device 52 is waterproof when it is not in the configuration of use in which it allows the insertion of the ballasting elements into the internal volume 32 of the barrel 26.

Advantageously, the device 52 comprises a hopper.

Advantageously, each module 24 comprises such a device 52.

Advantageously, at least one module 24 comprises a pressurization device 53 suitable for regulating the pressure prevailing in the interior volume 32 by injection of gas. This pressurization device 53 comprises for example a valve adapted to inject gas into the volume

32. This valve is for example arranged through the wall of the barrel 26, in the upper part thereof or in the upper obturation element 30.

The gas received by the pressurization device 53 comes, for example, from a compressor system.

It is noted that the pressurization device 53 can include several such valves.

In certain embodiments such as that illustrated in FIG. 2c, for at least certain modules, respective pressurization devices 53 of neighboring modules 24 are in fluid communication.

This makes it possible to pressurize the modules 24 in question by injecting gas from outside the module via a single module 24. In addition, this makes it possible to balance the pressures between the volumes 32 of the various modules 24 of the dead body 12.

This communication is for example implemented by one or more communication channels 53C (FIG. 3) each connecting the volumes 32 of two modules 24 to one another. Some communication channels extend for example between the barrels. Alternatively or in parallel, some extend in the obturation elements 28, 30 and in joints 56 between the modules described below.

The gas in question is for example compressed air.

It is noted that the pressurization device 53 is adapted to expel the water from the associated volume 32 via the device 50, and this by causing the drainage of the volume 32 of its water due to an overpressure caused by gas injection into the volume 32.

Advantageously also, at least one module 24 comprises at least one reinforcing element 55 (FIG. 3) adapted to reinforce the slab (s) 28, 30, and more precisely to reinforce them at the level of the part which projects beyond the barrel 26.

The element is for example in the form of one or more reinforcing crows mechanically connecting the barrel 26 to the part of the slab which projects beyond the barrel and which is turned towards the opposite slab.

The module 24 comprises for example a plurality of such elements 55 regularly spaced around the barrel 26.

Referring to Figure 3, at least one of the dead body modules 12 includes a connection device 54 for engaging the dead body 12 with the associated retaining cable or cables 14.

The connection device 54 comprises a connection beam fixed to the dead body 12. This beam is advantageously fixed to one of the shutter elements or to several shutter elements of adjacent modules 24.

Advantageously, it is fixed to the (or to) upper closure elements 30. This beam has a length, or grip, less than or equal to the diameter of a module 24.

The fixing of the beam is implemented by any known means, for example via a fixing means arranged at the level of the anchoring regions 37 of the prestressing elements 36 on the corresponding obturation element (s) ( s).

The connection device 54 further comprises an anchoring member for the retaining cable or cables 14 articulated on the beam. The anchoring member includes a passage for the cable or cables.

The articulation allows the angular deflections of the cable (s) 14.

Advantageously, the azimuthal orientation (considered in a local horizontal plane) of each retaining cable is aligned with the largest dimension of the dead body 12 in order to increase the torque resistant to overturning of this assembly.

Furthermore, advantageously, the position of the connection device 54 on the dead body 12 is chosen to minimize the overturning moment induced by the tensile force of the retaining cable (s) 14, that is to say - say the one that minimizes the distance of this effort to the center of gravity of the dead body.

Referring to Figure 4, and as indicated above, the modules 24 of a dead body 12 are mechanically secured to each other. Because of this solidarity, the dead body 12 is monolithic, that is to say that it behaves like an object in one piece.

In the context of the invention, advantageously, the modules 24 of each dead body 12 are juxtaposed, as opposed to stacked. In other words, they are arranged within a single stage, and not on top of each other at least for some within a plurality of stages.

Advantageously, a module 24 is made mechanically integral with a neighboring module 24 only by securing one or more shutter elements 28, 30 to one, respectively to the two shutter elements of the neighboring module 24 in question.

In other words, advantageously, the barrel of a module is not involved in the joining of the module 24 corresponding to the other modules other than indirectly, this joining being effected by fixing the shutter elements 28, 30 to each other. .

In more detail, for a given module 24, it is secured to an adjacent module 24 at least by fixing a slice T of its contour C to a slice of the contour C of the adjacent module by a seal 56 (Figures 2c , 3 and 4).

The slices T in question form respective interface regions of the modules 24 in play, via which the modules 24 are secured to the other modules 24 of the dead body 12.

These slices T are advantageously fixed to each other edge to edge and parallel to each other.

The seal 56 is for example made from an adhesive material such as epoxy glue. In this configuration, the seal 56 is for example formed by coating this material on one or both edges T.

Such a seal has a substantially zero thickness.

Optionally, the production of such seals calls for compression forces induced by so-called temporary prestressing elements, which can be temporarily received in the conduits 46 intended for the reception of the prestressing elements 48, which provide a so-called permanent prestressing.

Alternatively, the seal 56 is made by casting in place. In this configuration, the joint is for example made from a concrete or a mortar, such as for example a quick setting mortar. This joint configuration 56 is advantageously implemented in the case where a space is provided between the two wafers T.

This type of seal has a non-zero thickness.

The pouring in place is for example carried out according to a known process, and involves for example the installation of complementary reinforced concrete reinforcements and a formwork.

For the formation of seals 56, the modules are advantageously kept stationary relative to each other by a known invoice holding device.

Advantageously, for a given module 24, the two obturation elements 28, 30 are each secured to the obturation element of at least one neighboring module via such a seal 56.

In addition, advantageously, two adjacent modules are joined together via their lower shutter elements 28, and their upper shutter elements 30.

In other words, the joining of two adjacent modules 24 is advantageously carried out via their respective lower shutter elements, joined by a seal 56, as well as by their upper shutter elements 30, also joined by a seal 56.

Advantageously, the lower closure elements 28 are joined by seals 56 of the glued type, and the upper closure elements are joined by seals 56 cast in place.

However, the opposite configuration is envisaged. Alternatively, configurations with single joints 56 glued or with single joints 56 cast in place are used.

In the example of Figure 4, the slab 30 of the module 24 located in the foreground is thus joined by two of its sections T to a section T of a first adjacent module and to a section T of a second adjacent module. This configuration is preferably also reproduced for the lower slab 28, with joints 56 glued or poured in place.

As an alternative to these joints 56 or else parallel to them, and as indicated above, the mechanical connection of the modules 24 to each other is advantageously at least partly ensured by all or part of the prestressing elements 48, which are then received simultaneously in a plurality of closure elements and exert a force holding the corresponding closure elements integral.

Advantageously, this configuration is present for the lower slabs 28 and the lower slabs 30, and this advantageously for as many modules 24 of each dead body 12 as possible.

Preferably, the prestressing elements 48 are used together with the seals 56, which improves the monolithic nature of the dead bodies 12 and the resistance over time of the mechanical solidarity of the modules 24 with each other.

In these embodiments, the compression forces induced by the prestressing elements 48 passing through the seals 56 contribute substantially to the resistance of the latter.

It is also noted that the prestressing elements 48 in question pass through the joints 56, as illustrated in FIG. 2c.

With reference to FIGS. 5a to 5f, which illustrate the lower closure elements 28 of different dead body configurations 12 according to the invention, it is noted that the number and the relative arrangement of the modules 24 within a dead body 12 are easily adaptable.

In fact, each edge of the contour C forms a possible interface region with a neighboring module, each module being connected to a chosen number of modules between one and the number of the faces of the contour C.

A method of building a dead body 12 according to the invention will now be described with reference to the Figures, in particular to Figure 6 which illustrates the steps of the process.

In general, within the meaning of the invention, the process is based on the prefabrication of the drums 26 and the sealing elements 28, 30 of the modules 24 intended to form the dead body 12 from concrete, then the assembly of these elements so as to obtain a monolithic assembly of modules 24 within the meaning of the invention which is then placed on the seabed 11.

More specifically, during a step S1, for each module 24 of the dead body 12 intended to be formed, the barrel 26 and the obturation elements 28, 30 are manufactured.

For the barrel, if necessary, the segments 38 are manufactured.

These various elements are prefabricated from concrete, preferably reinforced concrete.

Their manufacture employs for example known techniques based on the pouring of concrete into a formwork in which is arranged a set, or cage, of passive reinforcements. This assembly includes for example the sheaths intended to define the prestressing conduits 34, 46.

During a step S2, for each module 24, the elements of the module 24 are relatively arranged with respect to each other so as to obtain their desired relative arrangement for the module during its use, and the modules 24 are arranged one in contact with others in the desired configuration of the dead body 12.

In other words, without yet fixing them, the elements of each module are reported to each other, and the same is done for the modules with one another. The relative position obtained is for example maintained by temporary holding means, for example known.

This step is advantageously carried out in the vicinity of the area in which the dead body 12 is subsequently launched for its movement to the seabed 11. This area is for example formed on a bank, a quay or other.

During a step S3, the shutter elements 28, 30 of the modules 12 are fixed to each other.

To do this, the prestressing elements 48 are put in place which ensure the horizontal prestressing of the obturation elements by passing them through the conduits 46 associated with the obturation elements that they are intended to clamp together, and they are anchored in the desired prestressing configuration in which they hold the shutter elements one with the other. In other words, the desired tightening is applied to the prestressing elements 48 and they are anchored.

During this step, prestressing elements 48 are preferably used in number and arrangement such that the dead body 12 forms a monolithic object. For example, each closure element 28, 30 is constrained in the direction of at least one other closure element 28, respectively 30 by at least one prestressing element 48.

In addition, the joints 56 are formed between the edges T of the contours C of the slabs 28, 30, as described above.

During a step S4, the elements of each module 24 are fixed to each other.

To do this, the joints 39 are formed between the segments 38 of the barrels 26, and the joints are formed between the barrels 26 and the associated sealing elements 28, 30.

In addition, the vertical prestressing elements 36 are put into place in each of the modules, and they are anchored in the desired prestressing configuration (that is to say they apply the desired tightening and anchor them ).

At the end of this step, the connection device (s) 54 are added to the dead body 12 to the corresponding module (s).

In a step S5, the dead body 12 is put into the water and it is moved in the direction of the plumb line of the seabed on which it is intended to rest. Advantageously, as indicated above, once launched, the dead body 12 is configured to float. The buoyancy of the dead body 12 is notably a function of the dimensions of the dead body and therefore of the number of modules, the diameter of the drums and the thickness of the walls of the drums and slabs.

This allows easy towing of the dead body 12 towards the vertical position of its resting point on the seabed 11.

Advantageously, for moving the dead body 12, auxiliary float devices are attached to the floating dead body, in order to increase the stability of the dead body 12 during the towing phase. The use of these floats is advantageously temporary. In other words, they are separated from the dead body 12 for the descent of the latter towards the seabed 11, as described below.

Advantageously, these floats are attached to the dead body 12 prior to the launching of the dead body 12 and are thus also used to increase the stability of the dead body 12 during its launching as such.

During an optional step S6, ballasting elements are inserted into the volume 32 of one or more drums via the corresponding device or devices 52. Advantageously, these elements are distributed homogeneously (in mass) between the barrels.

During a step S7, at least partial ballasting of the water drums is carried out by means of their device 50 so as to give the dead body 12 an apparent weight allowing the total immersion of the dead body while maintaining the weight carried by a device used for lowering / guiding the dead body 12 less than a predetermined value.

This device is for example a crane. This crane is for example on board a ship.

During a step S8, the dead body 12 is lowered towards the seabed 11 while guiding its descent.

This step is implemented via the above device.

Advantageously, during this descent, a predetermined fraction of the hydrostatic pressure exerted by the water on the modules 24 is compensated for and which increases as the descent increases the gas pressure inside the barrels 26 by means pressurization devices 53. This fraction is between 20% and 100% of the hydrostatic pressure in question.

Advantageously, the devices 53 fluidly communicate the volumes 32 of the different modules 24, thus making it possible to maintain respective pressures that are substantially identical in these volumes 32.

More specifically, for this compensation, the pressure inside the drums 26 is regulated during the descent of the dead body 12 to the seabed 11 by injection of gas into the drums considered via the devices 53, in order to maintain a level of flexion of the shutter elements 28, 30 of the modules 24 lower than a predetermined level.

Optionally, this operation includes the release of all or part of the gas contained in the interior volumes 32 via the device 53 for example, to lower, for example temporarily, the pressure in the drums.

As indicated above, the pressurization of the drums employs an external source of gas connected to at least one module 24. This source is for example at the level of the water surface, and is for example carried by a ship.

The devices 53 are thus used to inject pressurized gas into the volumes 32, possibly by communication between the (or the barrels) connected to this source and those which are not connected to this source.

At the end of step S8, the dead body 12 is placed on the seabed 11 at its position of use.

During a step S9, the volumes 32 are completely filled with water via the ballasting devices 50.

At this stage, the dead body 12 is in the configuration of use and can be connected to the structure 10 to ensure its anchoring.

To this end, the connection device 54 is connected to the retaining cable (s) 14.

Alternatively, this connection has er prior to the launching of the dead body 12.

In a step S10, which occurs at the end of the life of the dead body 12, the dead body 12 is brought to the surface. Advantageously, to do this, the volume 32 of the barrels 26 is emptied of all or part of the water which it contains to increase the buoyancy of the dead body 12 via the device 50. Advantageously, regulation of the pressure in the volumes 32 of the modules 24 via the devices 53, in a similar manner to what is done during step S8.

The invention is particularly advantageous. In fact, it makes it possible to obtain eminently adaptable anchor bodies at very low cost due to the concrete, prefabricated and modular nature of the main elements which make up the body.

In addition, the fact that the mechanical joining of the dead body 12 is mainly based on the fixing of the closure elements 28, 30 to each other, the drums are of more flexible dimensions insofar as the forces they have to be sized to support are less.

Note that in the above description, the dead bodies 12 have been described as comprising a plurality of modules 24 according to the invention secured to each other.

In a particular embodiment, a dead body 12 according to the invention comprises a single module 24. In other words, the dead body 12 is defined by a single module 24 according to the invention, in contrast to the above configurations in which a plurality of modules 24 is assembled to form the dead body 12.

In this configuration, one aspect of the invention relates to a dead body intended to be submerged and to anchor a floating structure, the dead body being formed by:

- a hollow cylindrical barrel, and

- two closure elements adapted to respectively seal opposite ends of the barrel.

Furthermore, in the above description, the shutter elements 28, 30 have been described as slabs. However, as a variant, their configuration, in particular their shape, is arbitrary. For example, the PI portion has a curved shape, advantageously convex, turned away from the barrel.

Claims (19)

1. Module for dead body (12) intended to be submerged and to anchor a floating structure, the module (24) comprising: - a hollow cylindrical barrel (26), and - two obturation elements (28, 30) adapted to respectively seal opposite ends of the barrel, the barrel and the obturation elements being of precast concrete, the module being intended to be mechanically integral with at least one other module of the dead body to form said dead body. 2. Module according to claim 1, further comprising at least one prestressing element (36) extending in the wall of the barrel (26) and having ends respectively anchored in one and the other of the closure elements . 3. Module according to claim 1 or 2, wherein at least one closure element has at least one interface region intended to be fixed to said other module for the formation of the dead body. 4. Module according to any one of the preceding claims, in which at least one obturation element has a polygonal contour (C). 5. Module according to claims 3 and 4, wherein the interface region corresponds to one of slices (T) of the polygonal contour of the at least one closure element. 6. Module according to any one of the preceding claims, in which the barrel (26) comprises a plurality of superimposed barrel segments (38). 7. Module according to any one of the preceding claims, in which each closure element receives at least one prestressing element (48) arranged in the thickness of the closure element substantially parallel to a plane of the element. shutter. 8. Module according to any one of the preceding claims, comprising a ballasting device (50) suitable for the controlled filling of the barrel (26) with water. 9. Module according to any one of the preceding claims, comprising a pressurization device (53) suitable for regulating a pressure prevailing in an interior volume (32) delimited by the barrel (26) by injection of gas into the volume interior (32). 10. Module according to any one of the preceding claims, in which the closure elements are in the form of tiles of general configuration of a flat plate. 11. Dead body configured for anchoring a floating structure (10), the dead body being intended to be immersed, the dead body (12) comprising a plurality of modules (24) according to any one of the preceding claims secured mechanically from each other. 12. Dead body according to claim 11, in which two adjacent modules (24) are mechanically secured to one another by fixing at least one of the closure elements of one of the two adjacent modules with at least one of the closure elements of the other of the two adjacent modules. 13. A dead body according to claim 11 or 12, in which sections of two respective closure elements (28, 30) of two adjacent modules are fixed to each other at least by a joint (56). 14. Dead body according to any one of claims 11 to 13, in which the dead body (12) comprises at least one prestressing element (48) received simultaneously in the respective closure elements of a plurality of said modules and exerting an effort maintaining the shutter elements of the corresponding modules secured to each other. 15. Dead body according to claims 13 and 14, wherein at least one prestressing element (48) received in the closure elements passes through said seal (56). 16. Method for building a dead body (12) for anchoring a floating structure (10), the method comprising: - precast, from concrete, hollow cylindrical drums and respective closure elements from a plurality of modules (24) each comprising a barrel (26) and two closure elements (28, 30) respectively closing ends opposite of the barrel, - from the drums and obturation elements, form an assembly mechanically secured to a plurality of said modules to form the dead body, and - arrange the dead body on a seabed. 17. The method of claim 16, wherein arranging the dead body (12) on a seabed (11) comprises regulating the pressure in an interior volume (32) of the barrel (26) of at least part of the modules during the descent of the dead body to the seabed by injection of gas into the barrels in order to maintain a level of flexion of the obturation elements of the corresponding modules below a predetermined level. 18. The method of claim 17, wherein the drums (26) of the modules of the dead body are at least partially filled with water for their establishment on the seabed. 19. The method of claim 18, further comprising removing the dead body from the seabed, said removal comprising at least partial emptying of the barrel of all or part of the water modules which the barrel (26) contains to increase the buoyancy of the corresponding modules.