FR3072980A1 - DEVICES AND METHODS FOR CONSTRUCTING FLOATING HABITABLE DIGUES - Google Patents

Abstract

The invention relates to devices and methods for constructing floating and habitable dikes for tourist purposes to protect the banks of tourist areas with high density of habitat that risk, in the near future, to be flooded by: - the rise of oceans resulting from global warming, increasing tides and tsunamis, - floods caused by violent thunderstorms leading to flooding of highly confined and often sloping habitable areas with no rainwater networks sufficient capacity, neither retention basins nor stable retaining walls. This invention not only protects the coastline by extension of the territory on the sea, but also it improves, the architectural and functional quality sought by the population, the profitability of investments and facilitating the connection with a platform barge implanted offshore.

Description

The invention relates to a device and a method for building floating and habitable dykes for tourist purposes, making it possible to protect the coastline against rising waters.

State of the art

The shores of tourist areas with a high density of habitat are likely, in the near future, to be flooded by:

- the rise of the oceans resulting from global warming, waves and tidal waves, increasingly violent typhoons and tsunamis and, floods caused by thunderstorms leading to flooding of heavily concrete habitable areas and often sloping, having neither rainwater networks of sufficient capacity, nor retention basins, nor stable retaining walls.

The latest scientific research shows that global warming, highlighted in the context of COP21, is causing the inevitable rise of the oceans in areas where building land is increasingly scarce, resulting largely from the spatial planning based on the specialization of equipment causing greenhouse gas emissions and water pollution.

The increase in population on the coast poses many technical and ecological problems, incompatible with the concepts of sustainable development and respect for the environment, such as:

Lack of building land;

Road congestion;

Air and water pollution;

Lack of potable water;

Growing difficulties in connecting to networks (wastewater, drinking water, electricity, waste, etc.);

Concreting of green spaces and forests in the hinterland for the creation of individual habitats, large shopping centers, or industrial zones (accessible only by car);

Climate change leading, in the near future, to the rise of the oceans and the flooding of beaches, roads and constructions by the sea.

In addition, the development, along the coast, of tourism, awaiting cultural sports and escape, requires the rapid adaptation of existing hotel facilities and beaches according to the requirements of an international clientele.

The most beautiful seaside sites, the most sought after by customers, are saturated and no longer allow new developments.

Unmanaged, poorly maintained and narrow beaches as well as parking difficulties along the roads would require significant development work, not only for the protection of areas that have become flooded (roads, beaches, habitats and industrial areas) due to the sea level rise, but also to meet tourist needs.

The problem of developing the seaside becomes essential:

- either we accept the floods, the reduction of the territory of our cities and our countries by moving the population, industrial, tourist and commercial activities (climatic emigration in different parts of the world);

- either we are looking for new solutions by contributing to the extension of the territory on the sea.

These new solutions are based on offshore construction technology. They mainly consist of:

- floating and habitable dykes that can be used commercially to protect flood-prone areas;

- integrated floating cities, autonomous in non-polluting energy to house the population and activities.

The problem of spatial planning along the sea and rivers concerns different specialties and different aspects and must have a vision at least a hundred years old, which is not currently the case for a large number of sites along the littoral.

Current techniques for building dykes, embankments or concrete, along the sea or rivers, in highly urbanized areas pose a number of difficulties:

- The developments located on the banks, consisting of roads, beaches and houses “feet in the water are often flooded;

- These constructions located on the banks, require the demolition and the 15 ’construction of dikes on new foundations instead of old foundations in poor condition;

- Dykes made off the coast using traditional techniques pose difficulties resulting from the need to build structures, below sea level, waterproof and resistant to corrosion for a period of at least 20,100 years;

- The designs of these dykes, made off the coast, tackling only technical problems, are difficult to absorb and gain acceptance by the local population and tourists who seek aesthetic solutions, preserving the environment and the quality of the life of the population (walks with sea view, green spaces, beaches, parking lots).

Summary of the invention

The present invention proposes a new concept of dam construction 30 applying a technology used in offshore platforms for oil, for the extension and the protection of the territory, instead of the reduction of the territory resulting from the rising waters caused by the global warming (CO2 = greenhouse effect).

Advantageously:

The dyke according to this concept makes it possible to protect the coastline against rising water and floods, by achieving an extension of the territory on the sea by floating dikes on several levels.

The dam along the areas to be protected is broken down into several partially prefabricated sections in a construction site.

The dimensions of each prefabricated section are defined according to the planned interior layout defined by the users, the characteristics of the construction site, and the towing weight defining the draft at the exit of the prefabrication site and at approach to mooring and installation areas near the banks to be protected.

This last constraint requires the reduction of the weight of the sections to be towed. Advantageously, the method of the invention allows the production of an outer envelope in direct contact with seawater, in a mixed steel-concrete structure where the steel structure ensuring the formwork contributing to the resistance and the sealing is partially coated with reinforced concrete located outside to prevent corrosion of the steel.

Each section constituting the outer envelope is composed:

- to strike - bottom in mixed structure;

- external walls in mixed structure concreted to a minimum height defined according to a draft in tow and heights of swells in tow;

- horizontal stiffeners embedded in the raft forming reinforced concrete partitions delimiting zones of ballasts and increasing the resistance of the raft;

- a high floor of the ballasts forming the floor of the car parks;

- compartments enclosing steel tubes, constituting a device for guiding, adjusting and lowering the tubes, ensuring after drilling, the descent and concreting, and the embedding of the dike in them in the ground.

The prefabricated sections are towed to an installation site with the steel tubes in the high position, immobilized in the compartments using a new mechanism.

Advantageously, the dyke designed and constructed according to the principle of the invention makes it possible to improve the profitability of investments and the architectural and functional quality of the coast, by the integration of public and tourist facilities 5 sought by investors, the inhabitants of the region and tourists, such as:

- walks, green spaces on different levels with sea views;

- restaurants, bars and shops;

- changing rooms and toilets;

- floating beaches, swimming pools or harbors;

- car parks on several levels;

- extensions of existing roads along the coast.

In alternative embodiments, habitats in upper floors can be integrated into the structure, with façades resistant to extreme 15 ‘pressures (wind, swell, tsunami).

Advantageously, the invention makes it possible to protect the sea against pollution by water coming from habitable or industrial zones located on sloping land, situated at the edge of the coast, by installations provided at the level of the ballasts, of the type:

- retention and filtration basins for polluted rainwater coming from sloping residential and industrial areas;

- reuse of filtered water for watering green plants, sanitary facilities on beaches and restaurants;

- basins for storage, filtration and reuse of rainwater from dikes;

- various technical premises sought by the city;

- thermal and photovoltaic solar panels for the production of electricity and for the heating and ventilation of habitable rooms.

To obtain the desired results, the present invention provides a method of manufacturing floating, habitable and multi-storey dikes, protecting the coastline against rising water and flooding, consisting of:

- prefabrication in the factory of boxes corresponding to the parts of the dike which are in direct contact with seawater, and to the internal structures of the dike ensuring its resistance;

- towing of the prefabricated caissons at an installation site; and

- assembly and assembly on the installation site of the boxes.

According to embodiments:

- the prefabricated boxes include immersed, waterproof walls, subject to corrosion, produced in a mixed steel-concrete structure ensuring very good mechanical resistance and very good corrosion resistance, and composed of:

- sheet steel located inside ensuring sealing and not subject to corrosion by seawater;

- angle stiffeners welded to the sheet ensuring the adhesion of concrete to steel and increasing the resistance of the walls;

- cellular T-stiffeners welded to the sheet ensuring the resistance of the walls;

- a transverse and longitudinal reinforcement;

- of concrete with the addition of a product ensuring the waterproofing of the concrete;

- an external formwork, collaborating in polished concrete with the addition of a resin-based component preventing the concrete from bursting and corrosion of the reinforcements.

- the prefabricated caissons are equipped with an adjustment system to ensure and adjust the descent of the anchor tubes during towing.

- the adjustment system also makes it possible to ensure the descent of the dyke under construction at the installation site.

- the adjustment system ensures the anchoring of the dike in the ground at the installation site.

- on-site assembly and assembly includes at least one drilling operation in the ground up to a level defined by calculation, embedding of anchoring tubes in the ground by concreting, laying on embankments or left floating , operations to finish the upper floors and the surrounding area.

- the adjustment system is a waterproof reinforced concrete structure composed of the following elements:

- a tube and a tube guiding and locking element;

- an upper and lower guide by a glued sandwich support ring ensuring the sliding and the transmission of the horizontal forces of the tube, and consisting of:

- a stiffened steel structure sealed in the concrete walls;

- neoprene;

- Teflon; and

- wedges and gussets supporting the weight of the tube.

- the adjustment system ensures that the tube is held in the high position and allows the tube to be lowered gradually using four gripper rings comprising several conical teeth and four hydraulic cylinders compressing the tube with variable pressure by pushing the grippers into the walls of the tube.

- the control of the adjustment system is carried out using a specific computer program.

The invention also covers a floating, habitable and multi-storey dike, protecting the coastline against rising water and flooding obtained by the claimed process.

Description of the figures

Figure 1 shows a perspective view of dikes and a connection with a platform-barge;

Figure 2 shows a cross section of a section of the dike for two solutions of height A and B, as well as the phases of towing and installation on site of the prefabricated elements of the dike;

Figure 3 shows examples of layouts of different levels;

Figure 4 provides details of towing and on-site installation of a prefabricated dike module;

Figure 5 shows details of the device for guiding, braking the descent and locking the steel tubes;

Figure 6 shows the walls of the prefabricated elements of the dike in direct contact with seawater, made in a mixed steel - concrete structure; and

Figure 7 shows an application of the invention for a floating dike on several levels.

Detailed description of the invention

Advantageously, the present invention recommends the installation of offshore dykes at a sufficient distance from the banks, taking into account the draft of the prefabricated elements in tow, the device facilitating installation on site and the quality of the seabed.

Advantageously, the present invention recommends breaking down the dikes into prefabricated caissons made in the factory (shipyard or yard), the internal dimensions of which are adapted to the dimensions of the car parks, possibilities of prefabrication in the factory and type of towing.

Advantageously, each prefabricated element can be produced either in a reinforced reinforced or prestressed concrete structure, or in steel, or in a mixed steel concrete structure.

Advantageously, in order to ensure perfect sealing and good corrosion resistance for a service life of more than 100 years, the present invention recommends making the part of the dam which is in direct contact with the seawater in structure. mixed steel - concrete; the steel ensuring the resistance and the sealing and the concrete ensuring the protection of the steel against corrosion.

This tightness and resistance to corrosion are difficult to obtain for concrete structures (resumption of concreting, fixing of formwork, removal of concrete, etc.) and steel structures (protection against corrosion for a lifetime of the dam. = 100 years).

Advantageously, the prefabricated elements suitable for towing are composed of the following elements:

- Radar constituting the bottom,

- Borders forming the outer walls,

- Double bottom (in the case of floating dikes undergoing significant hydrostatic and hydrodynamic pressures) enclosing the ballast compartments and the storage tanks, ensuring good resistance to bending due to hydrostatic and hydrodynamic pressure in service and during towing ,

- Compartments enclosing the guide tubes.

Advantageously, the height of the towed boxes is defined according to:

- the depth of the immersion,

- the height of the extreme swell,

- the height of the tides,

- estimated sea level rise in the implantation site,

- the estimated height of tsunami waves (in seismic zones).

Advantageously, the prefabricated elements of the dike in direct contact with seawater are made of waterproof concrete, the external surface of which forms the collaborating formwork made of composite mixture, is polished to prevent the concrete from bursting and the corrosion of the reinforcements.

Advantageously, the thicknesses of the walls are variable and justified by calculation as a function of the site of implantation and of the forces of hydrostatic and hydrodynamic pressures.

Advantageously, the compartments enclosing the steel tubes include a device allowing:

- blocking of the tubes during towing in the high position;

- lowering the tubes by sliding in the guides for anchoring the tubes in the ground (drilling and concreting);

- guiding the descent of the box during installation and construction; and

- the embedding of the tubes in the boxes at the end of construction.

Advantageously, the number of guide tubes and the length of anchoring in the ground can be adapted to the site of implantation and justified by calculation according to different parameters, in particular the horizontal and vertical forces taken up by:

- friction and pressure on the raft and on the soil compressed by the weight of the dam;

- shearing, traction or compression of the piers and the ground; and

- stop on reinforced concrete structures on the banks.

Advantageously during towing, the guide tubes are placed in the high position and maintained by a new device forming part of the invention;

Advantageously, the method of the invention allows ease and simplification of the installation on site by carrying out the following steps:

- installation of dykes off the coast at a distance chosen according to the depth of the sea adapted to the draft of prefabricated caissons;

- preparation of the seabed by the creation of embankments;

- positioning of the dam at the final location;

- inking using cables;

- lowering of guide tubes;

- drilling to a depth defined by calculation;

- installation of reinforcements and concreting of the tubes ensuring the anchoring of the caissons;

- work on the site: structure and layout of the different levels, symmetrically to ensure the gradual descent of the caissons according to the progress of construction;

- Sliding of the tubes in the Teflon guides, the control of the descent and the locking being ensured by a device controlled by computer forming the object of the present invention;

- the increase in the weight of the prefabricated sections as the concreting and interior layout progresses, ensures the gradual and symmetrical descent of the dyke;

- placing boxes on the embankments;

- blocking and embedding of the tubes at the end of construction by locking or / and concreting to ensure the transmission of forces;

- finishing of exterior and interior fittings;

- realization of the other sections according to the same process to ensure the continuity of the dam over the entire distance to be protected, while ensuring a good seal of the joints between the sections made;

The dikes can be either in a straight line or in a curve depending on the contour of the existing coastline.

Figure 1 shows a perspective view of a breakwater and a connection with a platform - barge. This barge may conform to that described in the French patent application of the applicant, published under the number 3037089.

- View 1A represents the submerged part with a tunnel (1), a walkway (2), piers (3) and a structure at the bottom of the ports of the barge (4).

- View 1B represents the barge platform, and the arrangement of the banks by extension to the sea, and consists of:

- a dike (5) made up of several prefabricated sections, comprising in this example, 3 levels of pedestrian circulation, beaches, shops, restaurants and parking lots;

- an entrance building (6) receiving the gangway and the tunnel;

- an extension of the road (7) by two lanes in each direction, a central reservation with green spaces, two cycle paths and two sidewalks.

FIG. 2 represents a cross section of a section of the dike for two solutions of height A and B as well as the towing and installation phases on the site of the prefabricated elements of the dike (A1 and B1),

The sea side façades (whose height h is predefined) and the structures (beaches, terraces and floating pontoons) are dimensioned to withstand the pressure of the swell, the rising of the waters, and the extreme wind (tsunami in seismic zones).

The height of the sea side façades is defined according to:

- the depth of the immersion,

- the height of the extreme swell,

- the height of the tides,

- estimated sea level rise in the implantation site,

- the estimated height of tsunami waves (in seismic zones).

More particularly, the following references represent:

(1) car parks whose layout plan determines the interior width of the dike;

(1a) a double bottom comprising ballasts and storage tanks increasing the resistance of the float bottom and the storage tanks for filtration and reuse of rainwater from dikes;

(2) technical rooms, locker rooms, toilets, beach attendants, bars;

(3) restaurants, bars and shops;

(4) and (5) walks, solariums, green spaces on different levels with sea views;

(6) floating beaches on pontoons;

(8) steel tubes filled with reinforced concrete to guide the descent and embedding of the dike;

(9) rainwater retention and filtration basins in sloping habitable areas;

(10) swimming pools or ports on the sea side;

R1 an existing road along the often flooded coastline;

R2 roads after extension;

R3 an extension of construction on the sea.

Figure 3 shows examples of layouts on different levels. He is shown :

(A): a double bottom;

(B): an entrance to parking lots and beaches, pontoons and swimming pools;

(C): a level of P2 walks with shops, restaurants, bars and sea views for walkers;

(D): a level of P1 walks or green flow with sea view, reserved for runners and walkers;

(R): restaurants, bars and shops.

More particularly, the following references represent:

(1) ballasts and tanks;

(2) compartments enclosing the guide tubes;

(3) parking lots;

(4) a double ramp;

(5) entry and exit to parking lots;

(6) beaches on consoles and P3 walks;

(7) beaches on floating pontoons;

(8) interior stairs and elevators;

(9) exterior stairs;

(10) seawater pools protected from jellyfish and sharks;

(11) breakwater and protection of swimming pools.

Figure 4 provides details of towing and on-site installation of a prefabricated dike module. It is shown the section by compartment ensuring the guidance of the anchor tube in different phases of installation:

(A) towing and positioning of the sections on a compacted embankment;

(B) construction on site, layout, upper levels, lowering of the elements as a function of increase in weight, installation of the box on the compacted embankments, drilling into the ground and lowering of the tubes, installation of reinforcement and concreting of anchor tubes;

(C) variant of the design: possibility of replacing the embankment with double-walled sliding doors, made of stainless steel, sunk into the ground to protect the coastline against rising water (high tides, tsunami, hurricanes)

More particularly, the following references represent:

(1) a towed prefabricated box ensuring the watertightness of the basements;

(2) a compartment enclosing the tube and the device for guiding the descent, locking and embedding of the tubes in the box;

(3) a lower guide ensuring the stop and the sliding of a tube;

(4) an upper guide ensuring the sliding of a tube and the locking in the high position for towing (see detail in figure 5);

(5) the bottom of the sea;

(6) compacted embankments;

(7) a “double-hung stainless steel guillotine-type door closure with ballasts for opening or closing;

(8) door support in the background, in reinforced concrete;

(9) a steel tube filled with reinforced concrete;

(10) a room filled with reinforced concrete at the end of the structural work.

Alternatively, the room (10) is not filled with concrete, allowing the dam to follow the tides by sliding in the rings (guides 3 and 4).

FIG. 5 shows the detail of the device for guiding, braking the descent and locking the steel tubes. He is shown :

(A) a plan view = horizontal section;

(B) a cross section C-C.

(D) detail of the guide (2) (fig. 5-D-2) and locking device (6) (Figure 5- B -6)

More particularly, the following references represent:

(1) a reinforced reinforced concrete structure reinforced by a metallic structure, enclosing the tube and the device for guiding and locking the tube (fig. 5-A-1 and 5-B-1);

(2) upper and lower guide “glued sandwich support ring (fig. 5-D-2 ensuring the sliding and the transmission of the horizontal forces of the tube made up of:

(3) a steel structure stiffened and sealed in the concrete walls (Fig. 5 - 3 D-3) (4) of neoprene (Fig. .5-D-4) (5) of teflon (fig. 5 - D-5) (6) a tube locking device, controlled by computer, ensuring that the tube is held in the high position and allowing the tube to be lowered progressively using 4 gripper rings (4) (Fig. 5 - B -4, Fig.5-D-6 and Fig. 5-A-4) comprising several teeth = grippers and 4 hydraulic cylinders (8) (fig. 5-A-8, fig.5-B-8 and fig. 5-D-8 compressing the tube with variable pressure (locking and / or sliding) by pushing the grippers = conical teeth (7) Fig. 5-D-7 into the walls of the tube See detail (D) gusset supporting the weight of the tube (fig. 5-D-10)

FIG. 6 represents the walls of the prefabricated elements of the dike in direct contact with seawater, made in a mixed steel-concrete structure and composed of:

(1) - a steel sheet located inside ensuring sealing and collaborating formwork, and not subject to corrosion by seawater, (fig. 6-1) (2) - stiffeners in angle iron welded on the sheet ensuring the adhesion of concrete to steel; (fig. 6-2) (3) - cellular frame stiffeners welded to the sheet ensuring the resistance of the walls; (fig. 6-3) (4) - a transverse and longitudinal reinforcement; (fig.6-4) (5) - concrete with the addition of waterproofing product; (fig. 6-5) (6) - a collaborating external formwork fixed on the reinforcements, in polished concrete or other material with the addition of a resin-based component preventing the concrete from bursting and corrosion of the reinforcements, the whole participating resistance and ensuring the tightness of the walls and protection against corrosion for a period of more than 100 years without external maintenance (fig. 6-6)

Figure 7 represents the detail of the doors represented on figure 4-C-7 and described on page 14 allowing to fulfill several functions according to the type of embedding of the dam in the piers (tubes filled with concrete and embedded in the soil) and dike supports at the bottom: on the embankment or in waterline (fig. 5- C-7).

A first solution consists of embedding the piles in the dike:

- by filling the room (10) fig. 7-A-10 with reinforced concrete (permanent embedding without the possibility of adjusting the draft);

- by embedding blocking by cylinders (fig.5-B-6 and fig. 7 - 4 (embedding with draft adjustment possibilities); and

- possibilities of closing or opening doors - guillotine.

A second solution consists in sliding the stacks in the sliding rings (fig. (3) allowing the rise or fall of the dyke according to the tides. Such a device is suitable for tides of +/- 3 m.

FIG. 7 A and B illustrates an application of the invention for a floating dike on several levels, with the draft and the tides of + - 3m, connected with the coast by articulated walkways allowing the movements of the dike and allowing if necessary to close the doors to protect the coastline against strong tides or a tsunami. In the case of the embedding of the tubes in the dam by concreting or locking, the dam and the foundations must resist the lifting forces resulting from the Archimedes push.

He is shown :

(A) fig. 7- Has a cross section at low tide (-3m);

(B) fig. 7- B a cross section at high tide (+ 3m);

(C) detail of guillotine doors controlled by ballasting; or

T is the draft and M the rise of tidal waters.

More particularly, the following references represent:

(1) a waterproof reinforced concrete structure enclosing the tube and the tube guiding and locking device; (fig. 7-A-1 and 7-B-1) (2) a compartment enclosing the tube and the device for guiding the descent, locking and embedding of the tubes in the box; (fig.7-A-2 and 7-B-2) (3) a guide ensuring the stop and the tube sliding; (fig. 7-A-3 and 7-B-3) (4) locking using cylinders (see detail in figure 5) (fig. 7-A-4 and 7-B-4) (5) the bottom of the sea; (fig.7-A-5 and 7-B-5) (7) the double-walled stainless steel “door hung” type door closers with ballasts for opening or closing; (fig.7-A-7 and 7-B-7) (8) the door supports in the reinforced concrete bottom; (fig. 7-A-8 and 7-B-8) (9) a steel tube filled with reinforced concrete embedded in the ground; (fig. 7-A-9 and 7-B-9) (10) a room filled with reinforced concrete to ensure embedding. (fig. 9-A-10 and 9-B-

10)

In more detail, (fiq. 7-C) shows the submersible guillotine doors with ballast:

(12) a wall of the mixed steel concrete structure (see detail in figure 6) composed of:

(71) of the steel sheet located inside ensuring sealing and not subject to corrosion by sea water;

(72) a stiffener in angles welded to the sheet ensuring the adhesion of the concrete on the steel;

(73) cellular frame stiffeners welded to the sheet ensuring the resistance of the walls;

(74) a transverse and longitudinal reinforcement;

(75) concrete with added sealant;

(76) a collaborating external formwork fixed on the frames, in polished concrete or other material with the addition of a resin-based component + teflon or other material allow the sliding of the doors;

(77) a stainless steel rail fixed to the crosspieces of the wall of the dike guiding the descent of the door;

(78) Teflon bonded to the inner part of the guide rail ensuring the sliding of doors;

(79) doors made up of several sections arranged between the guide rails, made of stainless steel with stiffeners and ballast compartment and a device for removing water and mounting the door or opening the valves, filling the ballasts and lowering the doors .

Thus, the present invention relates to devices and methods for manufacturing floating dikes, to protect the coastline against rising water and floods.

Advantageously, the construction of the multi-level box dam is broken down into four phases:

(1) Factory prefabrication of the part of the dyke which is difficult to carry out on site;

(2) Towing of the prefabricated part with tubes in the high position and positioning in the vicinity of the banks to be protected, with temporary inking using cables;

(3) Installation on site: lowering of the tubes, drilling into the ground to the level defined by calculation and progressive lowering of the tubes, fitting of reinforcements, concreting inside the tubes and embedding of the tubes in the ground;

(4) Work on site: finishing of planking structures, construction of interior structures, interior fittings, gradual and symmetrical descent of the dike and control of the descent using the computer, laying on the embankment, construction of the device for embedding tubes, finishing of upper floors and exterior areas.

Advantageously, the prefabricated elements include a device allowing:

- ensure and adjust the descent of the anchor tubes during towing;

- ensure the descent of the dike during construction on the site;

- to ensure the anchoring of the dam in the ground;

- ensure the management of installation operations on the site using a computer.

Claims (9)

claims 1. A method of manufacturing floating, habitable and multi-storey dikes protecting the coastline against rising water and flooding, consisting of: - a factory prefabrication of caissons corresponding to the parts of the dike which are in direct contact with sea water: Fig. 2: ref. (A1) and (B1) and to the internal structures of the dike ensuring its resistance Fig. 2: ref. (A), (A1), (B) and (B1) - a towing of the prefabricated caissons on an installation site: fig.2 ref. (A1) and (B1) and - assembly and assembly on the installation site of the boxes: Fig. 4 ref. (A) and (B) 2. The method according to claim 1, in which the prefabricated caissons comprise immersed, leaktight walls, subjected to corrosion, produced in a mixed steel-concrete structure ensuring very good mechanical resistance and very good corrosion resistance, and composed FIG. 6: - sheet steel located inside ensuring sealing and not subject to corrosion by seawater: Fig. 6 repo. (1) - angle stiffeners welded to the sheet ensuring the adhesion of concrete to steel and increasing the resistance of the walls; Fig. 6 ref. (2) - cellular T-stiffeners welded to the sheet ensuring the resistance of the walls; Fig. 6 ref. (3) - a transverse and longitudinal reinforcement; Fig. 6 ref. (4) - of concrete with the addition of a product ensuring the waterproofing of the concrete; Fig. 6 ref. (3) - an external formwork, collaborating in polished concrete with the addition of a resin-based component preventing the concrete from bursting and corrosion of the reinforcements. Fig. 6 ref. (5) 3. The method according to claim 1 or 2 in which the prefabricated caissons are equipped with an adjustment system making it possible to ensure and adjust the descent of the anchoring tubes during towing: Fig.3 ref. (A2) , Fig. 4 ref. (A), (B), (C), Fig. 5 ref. (A4), (B4), (B8), (D2), (D6), (D7) 4. The method of claim 3 wherein the adjustment system further ensures the descent of the dam during construction on the installation site. Fig. 4 ref. (A3) and ref. (B3) and Fig. 5 ref. (D)) 5. The method according to claim 3 or 4 wherein the adjustment system ensures the anchoring of the dike in the ground on the installation site: FIG.2 repo. (A) and (B) Fig. 4 ref. (A) and (B) 6. The method according to any one of claims 1 to 5 wherein the assembly and assembly on site comprises at least one drilling operation in the ground to a level defined by calculation, an embedding of anchoring tubes in the ground by concreting fig. 4 ref. (B10), an installation on embankment: fig. 4 ref. (6) or a float Fig. 4 ref. (C), finishing operations for the upper floors and the outside surroundings. Fig. 4 ref. (B), Fig. 6 ref. (4) 7. The method according to any one of claims 3 to 6 in which the adjustment system is a waterproof reinforced concrete structure composed of the following elements: - compartments enclosing the reinforced concrete guide tubes: Fig. 5 ref. (1), - a tube: Fig. 4 ref. (9) and a guide element: Fig. 4 ref. (3) and tube locking; and Fig. 4 ref. (2) and Fig. 5 ref. (D7) - an upper and lower guide by a glued sandwich support ring ensuring the sliding and the transmission of the horizontal forces of the tube: Fig.5 ref. (2,), and consisting of: - a stiffened steel structure sealed in the concrete walls; Fig. 5 ref. (D3) - compression plate ("neoprene" or equivalent) Fig.5 ref. D4) - sliding plate ("Teflon" or equivalent): Fig.5 ref D5. ; and - wedges and gussets supporting the weight of the tube. Fig. 5 ref. (B2) and (D10) 8. The method according to claim 7 wherein the adjustment system maintains the tube in the high position during the towing phase: Fig.2. (A1), and (B1) and allows the progressive descent of the tube using four gripper rings comprising: Fig. 5 repo. (4) several conical teeth: Fig. 5 ref. (D7) and four hydraulic cylinders: fig.5 ref. (8) compressing the tube with variable pressure by pushing in the grippers Fig. 5 repo. (7), in the walls of the tube. Fig. 5 ref. (9) 9. A floating, habitable, multi-storey dike protecting the coastline against rising water and flooding obtained by the process according to any one of claims 1 to 8.