A semi-taut mooring system and method of installing the same

Abstract

The application discloses a semi-taut mooring line damper and a mooring system and a method for installing the mooring system on a floating structure. The mooring system comprises at least three mooring assemblies, each of which comprises a damping system platform, at least two mooring lines and a pile foundation. The damping system platform comprises a working platform and a damping system. Each damping system comprises a winch, a steel cable, a connecting beam, a damper, a bracket, a guide rail frame, a limiting mechanism, a fairlead and a limiting pile. When the mooring system is used for mooring the floating structure, the mooring assemblies are uniformly distributed around the floating structure, the working platform is fixedly installed on the floating structure, the pile foundation is perpendicular to the sea bed mud surface and penetrates into the mud surface to a sufficient depth, and the top surface of the pile foundation reaches or is lower than the bottom surface of the floating structure. The application provides a favorable solution for the mooring engineering of the floating structure in the medium and shallow water area.

Description

Technical Field

[0001] This invention relates to the field of offshore floating wind power technology, and more particularly to a shallow-water mooring system with a semi-tensioned band damper and its installation method with a floating structure. Background Technology

[0002] With the increasing scarcity of global resources and the intensification of climate change, the demand for renewable and environmentally friendly energy supplies is constantly growing. Offshore wind energy has advantages such as being pollution-free, having large reserves, being renewable, having a stable wind source, and high wind speeds, making it highly favored among many new energy sources. To obtain high-speed and stable wind energy resources, offshore wind power technology has emerged.

[0003] my country boasts vast territorial waters and abundant wind energy resources, offering immense potential for wind power development. Currently, domestic offshore wind farms are primarily located in shallow waters, with most employing fixed foundations. The construction and installation costs of fixed wind turbines increase dramatically with water depth, and their development potential is limited by constraints imposed by wind energy resources and seawater depth. Therefore, expanding the application of offshore wind power using floating wind technology is of great significance.

[0004] Floating wind turbines are precisely positioned by connecting to the seabed foundation via mooring lines. Different mooring methods result in significantly different restoring forces from the mooring lines, leading to substantial variations in mooring costs. Currently, common mooring methods for offshore floating wind turbines include catenary, semi-tensioned, and tensioned mooring systems. The restoring force of a catenary mooring system primarily comes from the weight of the suspended mooring line, with a pre-laid flat section at the bottom in contact with the seabed. Because a large mooring radius is required to ensure the catenary effectively limits the flow of water in harsh conditions, this significantly increases the cost of the system, especially in shallow to medium water. Semi-tensioned and tensioned mooring systems do not require contact with the seabed, and their mooring radii are much smaller than those of catenary mooring systems. However, the mooring line always intersects the seabed at a certain angle, causing the seabed foundation to bear large horizontal and vertical forces, increasing the risk of anchorage loss and reducing the reliability of mooring performance. In addition, under the action of wind, waves and currents, the mooring line is in a state of cyclic tension and rebound stress, which requires high fatigue resistance of the mooring line material and increases mooring costs.

[0005] In order to meet the safety and economic requirements of developing floating wind turbines in water depths of 50 to 150 meters under the new circumstances, ensure the positioning of offshore wind power in the sea area, and limit the swaying and pitching motion of the overall structure of floating wind turbines under the combined action of wind, waves and currents, it is necessary to optimize and improve the mooring and positioning methods of floating offshore wind power to adapt to its development and promotion needs. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, the present invention provides a semi-tensioned band damper mooring system for shallow water and a method for installing it with a floating structure.

[0007] The present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a semi-tensioned band damper mooring system for shallow water, comprising at least three mooring assemblies, each mooring assembly including a damping system platform, at least two mooring cables, and pile foundations; the damping system platform includes a working platform and a number of damping systems arranged side-by-side, the same number as the number of mooring cables; each damping system includes a winch, a steel cable, a connecting beam, a damper, a bracket, a guide rail frame, a limiting mechanism, a guide cable roller, and a limiting pile; the winch, the guide rail frame, the guide cable roller, and the limiting pile are sequentially fixed to the top surface of the working platform along the length direction of the guide rail frame; tracks are provided on both sides of the guide rail frame along its length direction, and the limiting mechanism is provided at both ends of the tracks; the connecting beam and the bracket are supported on the tracks on both sides of the guide rail frame and can only move between the limiting mechanisms along the length direction of the tracks. Within a predetermined range, one end of the steel cable is wound and fixed to the drum of the winch, and the other end of the steel cable is connected to the connecting beam. The damper is fixed to the bracket, and one end of the damper is connected to the connecting beam. The upper part of the mooring cable passes through the limiting pile and falls into the groove of the guide roller. The upper end of the mooring cable is connected to the other end of the damper. The lower end of the mooring cable is connected to the portion of the pile foundation in the water. When the shallow-medium water mooring system is used for mooring floating structures in shallow-medium water, the mooring components are evenly distributed around the floating structure. The working platform of the damping system platform is fixedly installed on the floating structure. The pile foundation is perpendicular to the seabed mud surface and penetrates to a sufficient depth below the mud surface. The top surface of the pile foundation in the water reaches or is lower than the bottom surface of the floating structure.

[0009] Secondly, the present invention provides an installation method for connecting the shallow-to-medium water mooring system described in the first aspect to a floating structure, comprising the following steps:

[0010] S1. Connect the lower end of the mooring cable of each set of mooring components to the pile foundation and the upper end to the float;

[0011] S2. The mooring cables and pile foundations assembled in step S1 are towed to the designated machine location by barge.

[0012] S3. Use a crane to lower the pile foundations to the predetermined machine site in sequence and drive the piles into the seabed. After reaching the predetermined depth, the pile driving operation is completed. The pile foundations are already connected to mooring cables.

[0013] S3. The damping system platform for each set of the mooring components is installed on land;

[0014] S4. Tow the floating structure to the predetermined landing site;

[0015] S5. Remove the floats from the upper end of each mooring cable, hoist the upper end of the mooring cable to the damping system platform, use the traction rope to make the upper part of the mooring cable pass through the limit pile and the guide roller, and then connect the upper end of the mooring cable to the damper to complete the installation of a set of mooring components.

[0016] S6. Repeat the above steps until all mooring components are connected to the floating structure. Apply pretension to the mooring cable by adjusting the damper and controlling the winch operation to complete the installation.

[0017] Compared with existing technologies, the mooring system of this invention is particularly suitable for use in shallow to medium-depth waters with a depth of 50m to 150m. Compatible offshore floating structures include, but are not limited to, floating wind turbines, semi-submersible drilling platforms, and floating aquaculture cages. Its beneficial technical effects include:

[0018] (1) The mooring system of the present invention can shorten the mooring radius, reduce the area of ​​the seabed occupied by the mooring system, and reduce the construction cost of the mooring system.

[0019] (2) The mooring system of the present invention combines a damping system platform and arranges dampers in the horizontal direction, which can effectively absorb the kinetic energy of the floating structure and the impact energy released by the rebound of the mooring cable, reduce the horizontal movement of the floating structure, and reduce the material loss of the mooring cable under reciprocating load.

[0020] (3) In the mooring system of the present invention, each mooring assembly has no fewer than two mooring cables. If one cable fails, the other can continue to perform the mooring function, ensuring the reliability and redundancy of the mooring system. In addition, the damper is located above the water surface, and each mooring cable can be disassembled independently, facilitating inspection, recovery, or repair.

[0021] (4) The mooring system of the present invention is easy to install and easy to construct. Most of the mooring components are assembled on land, which reduces the construction cost.

[0022] In the preferred embodiment, the mooring cable of the present invention has a small horizontal angle with the horizontal plane, which can provide a large horizontal restoring force for floating structures and has excellent mooring performance.

[0023] In the preferred technical solution, at least three small-diameter steel cables are used to fix the winch. Since the bending radius of the small-diameter steel cables is smaller, it is beneficial to improve the bending fatigue characteristics of the steel cables, further improve the service life of the mooring system, and significantly reduce the maintenance costs in the later stage.

[0024] In summary, the semi-tensioned band damper mooring system provided by this invention can provide sufficient horizontal restoring force for floating structures, shorten the mooring radius, reduce the rebound and tumbling phenomenon of the mooring cable, and improve the service life of the mooring cable. This mooring system is easy to install and simple to construct, reducing construction and maintenance costs, and providing a favorable solution for mooring engineering of floating structures in shallow and medium waters. Attached Figure Description

[0025] Figure 1 This is a perspective view of the mooring system connected to a floating structure in a specific example of the present invention.

[0026] Figure 2 yes Figure 1 The main view.

[0027] Figure 3 yes Figure 1 Top view.

[0028] Figure 4 yes Figure 1 A three-dimensional schematic diagram of the damping system platform.

[0029] Figure 5 This is a structural diagram of the mooring cable in a specific embodiment of the present invention.

[0030] Figure 6 This is a diagram showing the internal structure of the damper in a specific embodiment of the present invention. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, used only to facilitate and clearly illustrate the embodiments of the present invention. Please refer to the drawings to make the objectives, features, and advantages of the present invention more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the implementation conditions of the present invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to the size, without affecting the effects and objectives achieved by the present invention, should still fall within the scope of the technical content disclosed in the present invention.

[0032] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be directly on or indirectly on the other component. When a component is referred to as "connected to" another component, it can be directly connected to or indirectly connected to the other component. Furthermore, a connection can be used for fixing, coupling, or communication.

[0033] This invention provides a semi-tensioned band damper mooring system for shallow water (hereinafter referred to as the mooring system), comprising at least three mooring assemblies. Each mooring assembly includes a damping system platform, at least two mooring cables, and pile foundations. The damping system platform includes a working platform and a number of damping systems arranged side-by-side, the same number as the mooring cables. Each damping system includes a winch, a steel cable, a connecting beam, a damper, a bracket, a guide rail frame, a limiting mechanism, a guide cable roller, and a limiting pile. The winch, the guide rail frame, the guide cable roller, and the limiting pile are sequentially fixed to the top surface of the working platform along the length of the guide rail frame. Rails are provided on both sides of the guide rail frame along its length, and the limiting mechanism is provided at both ends of the rails. The connecting beam and the bracket are supported on the rails on both sides of the guide rail frame and can only move along the length of the rails within the limiting mechanism. The mooring mechanism moves within a predetermined range, one end of the steel cable is wound and fixed to the drum of the winch, the other end of the steel cable is connected to the connecting beam, the damper is fixed to the bracket, one end of the damper is connected to the connecting beam, the upper part of the mooring cable passes through the limiting pile and falls into the groove of the guide roller, the upper end of the mooring cable is connected to the other end of the damper, and the lower end of the mooring cable is connected to the part of the pile foundation in the water; when the shallow-medium water mooring system is used for mooring floating structures in shallow-medium water, the mooring components are evenly distributed around the floating structure, the working platform of the damping system platform is fixedly installed on the floating structure, the pile foundation is perpendicular to the seabed mud surface and penetrates to a sufficient depth below the mud surface, and the top surface of the pile foundation in the water reaches or is lower than the bottom surface of the floating structure.

[0034] In the technical solution of this invention, the mooring cable rests in the groove of the guide roller, which guides the mooring cable (constraining the mooring cable and changing its force transmission direction). The contact area between the mooring cable and the guide roller is small, effectively reducing wear on the mooring cable. However, when the floating structure undergoes heaving, rolling, or pitching movements, the mooring cable is prone to displacement or detachment. To solve these problems, an adjustable limiting post is used in front of the guide roller to constrain the mooring cable (i.e., the limiting post prevents displacement or detachment of the mooring cable during heaving, rolling, or pitching movements of the floating structure). The limiting mechanism limits the movement range of the connecting beam and the bracket, the bracket supports the damper, and the guide rail frame limits the movement direction of the damper and the force transmission direction of the damping system. With the above technical solution of this invention, the winch is in a braking state during use of the mooring system. If the floating structure deviates from its equilibrium position, the damping system platform moves the mooring cable away from the pile foundation. The winch, steel cable, and connecting beam sequentially transfer the environmental load on the floating structure to the damper, mooring cable, and finally to the pile foundation. During this process, the damper is stretched, absorbing the kinetic energy of the floating structure and thus reducing its amplitude. Simultaneously, the mooring cable undergoes elastic tensile deformation, and with a small horizontal angle between the mooring cable and the horizontal plane, it generates a large horizontal restoring force opposite to the displacement direction of the floating structure, thereby restricting its movement. When the floating structure moves to its equilibrium position, the mooring cable quickly releases its load, and the damper absorbs the impact energy released by the mooring cable, mitigating the rebound and jerking phenomenon of the mooring cable.

[0035] In a preferred embodiment, each of the damping systems includes at least three steel cables, and the winch drum has the same number of grooves as the steel cables, with the at least three steel cables respectively wound into the grooves on the winch drum; in each mooring assembly, the mooring cables are two or three.

[0036] One end of each of the multiple steel cables is wound and fixed to the drum of the winch, and the other end is connected to the connecting beam. The multiple steel cables work together to transfer the load on the winch to the connecting beam.

[0037] In a preferred embodiment, when the shallow-medium water mooring system is used for mooring a floating structure in shallow-medium water, one side of the working platform (the side near which the winch is located) is fixed to the outside of the floating structure, the top surface of the working platform is lower than the bottom surface of the deck of the floating structure, and the top surface of the working platform is higher than the still water surface.

[0038] In a preferred embodiment, the limiting stake is an adjustable grid-shaped limiting stake, with both the upper and lower crossbars being detachable and adjustable, and the upper part of the mooring cable passes between the upper and lower crossbars of the limiting stake.

[0039] Since the joints of the mooring cable are relatively large and difficult to pass through the limit stakes, the preferred solution is to use a grid-shaped limit stake with detachable and adjustable upper and lower crossbars, which can facilitate the installation of the mooring cable.

[0040] In a preferred embodiment, the lower end of the mooring cable is connected to an anchor point on the outer wall 2 to 3 meters below the bottom surface of the pile foundation.

[0041] In a preferred embodiment, the diameter of the steel cable is smaller than the diameter of the mooring cable; the material of the steel cable is the same as that of the mooring cable. For example, both the mooring cable and the steel cable are high-strength single-strand steel wire ropes, made of twisted round steel wires. The steel wires are thick-coated galvanized steel wires and coated with a marine-specific lubricant. The steel wire rope is wrapped with a medium-density or high-density polyethylene sheath, which is bright in color and has a black straight line along the axial direction.

[0042] In a preferred embodiment, in each of the mooring assemblies, the angle between adjacent mooring cables is less than 5°, and when the mooring cable is under tension, the angle between the mooring cable and the horizontal plane is between 5° and 15°.

[0043] In a preferred embodiment, the pile foundations are symmetrically arranged around the floating structure, and the number of pile foundations is the same as the number of mooring assemblies. The number of mooring assemblies is 3 or 4. When the number of mooring assemblies is 3, the angle between the angle bisectors of the horizontal projections of the two outermost mooring cables in each set is 120°. When the number of mooring assemblies is 4, the angle between the angle bisectors of the horizontal projections of the two outermost mooring cables in each set is 90°.

[0044] In a preferred embodiment, the pile foundation is a cylindrical or polygonal long column, the top surface of which is the surface on which the offshore pile driver hammers. The outer diameter of the pile foundation is 4000-6000 mm, and the wall thickness is 40 mm-100 mm.

[0045] In a preferred embodiment, the damper is a waterproof hydraulic damper, whose main components include an outer cylinder, a hydraulic cylinder, a piston rod, an oil reservoir, a spring, a damping control valve, and connectors. These components are connected in a manner known in the art and will not be described in detail here. The outer layer of the damper is made of thick-walled stainless steel; the total rated load of the damper is not less than the minimum breaking load of the mooring cable; the damper has sufficient stroke, and the piston rod can continue to move when the floating structure experiences maximum horizontal displacement and rotation, so as to ensure that the damper fully exerts its energy dissipation function.

[0046] A specific embodiment of the present invention also provides an installation method for connecting the semi-tensioned band damper in a shallow-water mooring system to a floating structure, which includes the following steps:

[0047] S1. Connect the lower end of the mooring cable of each mooring assembly to the pile foundation and the upper end to the float.

[0048] S2. The mooring cables and pile foundations assembled in step S1 are towed to the designated machine location by barge.

[0049] S3. Use a crane to lower the pile foundations to the predetermined machine site in sequence and drive the piles into the seabed. After reaching the predetermined depth, the pile driving operation is completed. The pile foundations are already connected to mooring cables.

[0050] S3. The damping system platform for each set of the mooring components is installed on land;

[0051] S4. Tow the floating structure to the predetermined landing site;

[0052] S5. Remove the floats from the upper end of each mooring cable, hoist the upper end of the mooring cable to the damping system platform, use the traction rope to make the upper part of the mooring cable pass through the limit pile and the guide roller, and then connect the upper end of the mooring cable to the damper to complete the installation of a set of mooring components.

[0053] S6. Repeat the above steps until all mooring components are connected to the floating structure. Apply pretension to the mooring cable by adjusting the damper and controlling the winch operation to complete the installation.

[0054] Below, in conjunction with the appendix Figures 1-6 The above-mentioned semi-tensioned band damper shallow water mooring system and its installation method with floating structures will be further illustrated by a specific example.

[0055] A schematic diagram of the connection structure between the floating structure and the mooring system is shown below. Figure 1 As shown, the mooring system comprises four mooring assemblies symmetrically and evenly distributed around the floating structure 4. Each mooring assembly includes a damping system platform 1, two mooring cables 2, and a pile foundation 3. One end of each mooring cable 2 is connected to the damping system platform 1, and the other end is connected to an anchor point on the outer wall 2 meters from the top surface of the pile foundation 3. The pile foundation 3 is perpendicular to the seabed mud surface and penetrates to a sufficient depth below the mud surface, i.e., the lower part of the pile foundation penetrates to a sufficient depth below the mud surface. The upper part of the pile foundation is located in the water, and the top surface of the pile foundation in the water reaches or is lower than the bottom surface of the floating structure 4. The height of the top surface of the pile foundation is slightly lower than the bottom surface of the floating structure 4. Figure 2 As shown, this provides reliable load-bearing capacity for the entire mooring system.

[0056] like Figure 4As shown, the damping system platform 1 includes a working platform 5 and a number of damping systems arranged side by side, the same number as the number of mooring cables (in this example, there are 2 damping systems, one damping system corresponds to one mooring cable 2). Each damping system includes a winch 6, 3 steel cables 7, a connecting beam 8, a damper 9, a bracket 10, a guide rail frame 11, a limiting mechanism 12, a guide roller 13, and a limiting stake 14. The winch 6, guide rail frame 11, guide cable roller 13, and limit stake 14 are sequentially fixed to the top surface of the working platform 5 along the length of the guide rail frame 11 (that is, along the length of the guide rail frame 10, from one end of the top surface of the working platform 5 to the other end, the winch 6, guide rail frame 11, guide cable roller 13, and limit stake 14 are arranged sequentially); the guide rail frame 11 has rails 15 on both sides along its length, and each rail 15 has a limit mechanism 12 at both ends; the three steel cables 7 of each damping system are made of the same material and type as the mooring cable 2, but the diameter of the steel cables 7 is smaller than the diameter of the mooring cable 2; the drum of the winch 6 has three rope grooves 16 and three steel cables 7 One end of the cable is wound and fixed in the three rope grooves 16 of the winch 6, and the other end is connected to the connecting beam 8. The connecting beam 8 and the bracket 10 are both supported on the two side rails 15 of the guide rail frame 11. The connecting beam 8 is located between the winch 6 and the bracket 10. The connecting beam 8 and the bracket 10 can move along the rail 15 within a certain range. The damper 9 is fixed on the bracket 10. Both ends are fixedly connected to the connecting beam 8 and the mooring cable 2, respectively. After the upper part of the mooring cable 2 passes through the limiting pile 14 and falls into the groove of the guide cable roller 13, its upper end is connected to the other end of the damper 9. The lower end of the mooring cable 2 is connected to the part of the pile foundation 3 in the water (the outer wall anchor point 2 meters away from the top surface of the pile foundation 3). In this example, the limiting stake 4 is an adjustable grid-shaped limiting stake, with both the upper and lower crossbars being detachable and adjustable. The upper part of the mooring cable 2 passes between the upper and lower crossbars of the limiting stake. By setting the grid-shaped limiting stake, displacement and detachment of the mooring cable 2 are prevented when the floating structure is heaving, rolling, or pitching. Figures 1-3 As shown, the working platform 5 is fixed to the outside of the floating structure 4. The top surface of the working platform 5 is lower than the bottom surface of the deck of the floating structure 4, and the top surface of the working platform 5 is higher than the still water surface.

[0057] like Figure 5 As shown, the mooring cable 2 and the steel cable 7 are made of high-strength single-strand steel wire rope, twisted from round steel wires 21 coated with a thick galvanized layer, and coated with a special lubricant. The steel wire rope is wrapped with a medium-density or high-density polyethylene sheath 22, which is bright in color and has a black straight line 23 along the axial direction as a marker line for underwater observation of the mooring cable. The damper 9 is a hydraulic damper, and its internal structure is as follows... Figure 6As shown, the main components include an outer cylinder body 91, a hydraulic cylinder 92, an oil reservoir 93, a piston rod 94, a spring 95, a damping control valve 96, and a connector 97. These components are connected in a manner known in the art and will not be described in detail further. The entire outer layer of the damper in contact with the outside world is made of thick-walled stainless steel. The total rated load of the damper 9 is not less than the minimum breaking load of the mooring cable 2. The damper 9 has sufficient stroke, and the piston rod 94 can continue to move when the floating structure 4 experiences maximum horizontal displacement and rotation, ensuring that the damper 9 fully utilizes its energy dissipation function.

[0058] In each mooring assembly, the angle between adjacent mooring cables is less than 5° (the two adjacent mooring cables are arranged in a V-shape, with the lower ends of the two mooring cables as the vertices, and the included angle is less than 5°). For example... Figure 3 As shown, the angle α between the angle bisectors (dashed lines in the figure) of the horizontal projections of the two outermost mooring cables of each set 6 is 90°; Figure 2 As shown, when the mooring cable is under tension, the horizontal angle β between it and the horizontal plane is between 5° and 15° (9° in this example). In actual engineering applications, the floating structure 4 will shift to a certain extent under the influence of wind, waves, and currents, and the magnitude of the above angle will deviate to some extent.

[0059] In use, the winch 6 of the mooring system of the present invention is in a braking state. If the floating structure 4 deviates from its equilibrium position, the damping system platform 1 drives the mooring cable 2 away from the pile foundation 3; the winch 6, the three steel cables 7, and the connecting beam 8 sequentially transfer the environmental load on the floating structure 4 to the damper 9, the mooring cable 2, and finally to the pile foundation 3. During this process, the piston rod 94 of the damper 9 is stretched, absorbing the kinetic energy of the floating structure 4, thereby reducing the amplitude of the floating structure 4's movement; at the same time, the mooring cable 2 undergoes elastic tensile deformation, and the horizontal angle between the mooring cable and the horizontal plane is small, generating a large horizontal restoring force opposite to the displacement direction of the floating structure 4, thereby restricting the movement of the floating structure 4; when the floating structure 4 moves to the equilibrium position, the mooring cable 2 quickly unloads the force, and the piston rod 94 of the damper 9 slowly retracts, thereby absorbing the impact energy released by the mooring cable 2 and weakening the rebound and tumbling phenomenon of the mooring cable 2.

[0060] In this invention example, the installation method of the mooring system and the floating structure is as follows:

[0061] (1) Connect the lower end of the mooring cable 2 of each mooring assembly to the pile foundation 3 and the upper end to the float;

[0062] (2) The assembled mooring cable 2 and pile foundation 3 are towed to the designated machine site by barge;

[0063] (3) The damping system platform 1 of each mooring assembly is installed on land. In this example, specifically, the winch 6, guide rail frame 11, guide cable roller 13 and limit pile 14 are fixed to the top surface of the working platform 5 along the length of the guide rail frame 11. The damper 9 is fixed on the bracket 10. One end of the damper 9 is fixedly connected to the connecting beam 8. The two ends of the steel cable 7 are respectively connected to the drum of the winch 6 and the connecting beam 8. The bracket 10 and the connecting beam 8 are installed on the two side rails 15 of the guide rail frame 11. The two horizontal bars at the top of the limit pile 14 are to be installed.

[0064] (4) Tow the floating structure 4 to the predetermined machine position; remove the floats from each mooring cable 2, use a crane or other facilities to lift the upper end of the mooring cable 2 to the damping system platform 1, and use the traction rope to make the mooring cable 2 pass through the guide roller 13 and the limiting pile 14, and then connect it to the damper 9. Finally, install the two crossbars on the upper part of the limiting pile 14 to complete the installation of a set of mooring components.

[0065] (5) Repeat the above steps until all mooring components and floating structures in the entire mooring system are connected. Then, apply pretension to the mooring cable 2 by adjusting the damping control valve 96 of the hydraulic damper 9 and controlling the winch 6, thereby completing the installation.

[0066] The mooring system of this invention is particularly suitable for floating structures in shallow to medium waters of 50 to 150 meters, and has a wide range of applications. Suitable offshore floating structures include, but are not limited to, floating wind turbines, semi-submersible drilling platforms, and floating aquaculture cages. The embodiments of this invention have the following advantages:

[0067] 1. The mooring cable has a small horizontal angle with the seabed, which can provide a large horizontal restoring force for floating structures and has excellent mooring performance.

[0068] 2. Mooring systems can shorten the mooring radius and reduce the area of ​​the seabed occupied by the mooring system.

[0069] 3. The mooring system is equipped with a damping system with hydraulic dampers in the horizontal direction, which can effectively absorb the kinetic energy of the floating structure and the impact energy released by the rebound of the mooring cable, reduce the horizontal movement of the floating structure, and reduce the material loss of the mooring cable under reciprocating loads, thereby improving the service life of the mooring system.

[0070] 4. The mooring system is easy to install and construct. The assembly of the mooring system is mostly carried out on land, which reduces the construction cost and provides a reasonable solution for mooring projects of floating structures in shallow and medium waters.

[0071] The mooring system in the example above has four mooring units, each with the same number of mooring cables. In other examples, there could be three or more mooring units. Each mooring unit in the example above has two mooring cables; in other examples, there could be three or more mooring cables.

[0072] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, several equivalent substitutions or obvious modifications can be made without departing from the concept of the present invention, and all such modifications, achieving the same performance or purpose, should be considered within the scope of protection of the present invention.

Claims

1. A semi-tensioned band damper mooring system for shallow water, characterized in that, It includes at least three mooring assemblies, each of which includes a damping system platform, at least two mooring cables, and pile foundations; The damping system platform includes a working platform and a number of damping systems arranged side-by-side, the same number as the mooring cables. Each damping system includes a winch, a steel cable, a connecting beam, a damper, a bracket, a guide rail frame, a limiting mechanism, a guide cable roller, and a limiting post. The winch, the guide rail frame, the guide cable roller, and the limiting post are sequentially fixed to the top surface of the working platform along the length of the guide rail frame. Rails are provided on both sides of the guide rail frame along its length, and the limiting mechanism is installed at both ends of the rails. The connecting beam and the bracket are supported on the platform. The guide rail is mounted on the rails on both sides of the guide rail frame and can move within a predetermined range between the limiting mechanisms along the length of the rails. One end of the steel cable is wound and fixed to the drum of the winch, and the other end of the steel cable is connected to the connecting beam. The damper is fixed to the bracket, and one end of the damper is connected to the connecting beam. The upper part of the mooring cable passes through the limiting pile and falls into the groove of the guide cable roller. The upper end of the mooring cable is connected to the other end of the damper, and the lower end of the mooring cable is connected to the part of the pile foundation that is in the water. When the shallow-medium water mooring system is used for mooring floating structures in shallow-medium water, the mooring components are evenly distributed around the floating structure, the working platform of the damping system platform is fixedly installed on the floating structure, the pile foundation is perpendicular to the seabed mud surface and penetrates to a sufficient depth below the mud surface, and the top surface of the pile foundation in the water reaches or is lower than the bottom surface of the floating structure.

2. The shallow-water mooring system with a semi-tensioned band damper as described in claim 1, characterized in that, Each of the damping systems comprises at least three steel cables, and the winch drum has the same number of grooves as the steel cables, with the at least three steel cables respectively wound into the grooves on the winch drum.

3. The shallow-water mooring system with a semi-tensioned band damper as described in claim 1, characterized in that, When the shallow-medium water mooring system is used for mooring floating structures in shallow-medium water, one side of the working platform is fixed to the outside of the floating structure, the top surface of the working platform is lower than the bottom surface of the deck of the floating structure, and the top surface of the working platform is higher than the still water surface.

4. The shallow-water mooring system with a semi-tensioned band damper as described in claim 1, characterized in that, The limiting stake is an adjustable grid-shaped limiting stake, and both the upper and lower crossbars can be disassembled and adjusted. The upper part of the mooring cable passes between the upper and lower crossbars of the limiting stake.

5. The shallow-water mooring system with a semi-tensioned band damper as described in claim 1, characterized in that, The lower end of the mooring cable is connected to the anchor point on the outer wall 2 to 3 meters below the bottom surface of the pile foundation.

6. The shallow-water mooring system with a semi-tensioned band damper as described in claim 1, characterized in that, The diameter of the steel cable is smaller than that of the mooring cable; the material of the steel cable is the same as that of the mooring cable; in each mooring assembly, there are 2 or 3 mooring cables.

7. The shallow-water mooring system with a semi-tensioned band damper as described in claim 1, characterized in that, In each of the mooring assemblies, at least two mooring cables have an angle of less than 5° between adjacent mooring cables, and when the mooring cable is under tension, the angle between the mooring cable and the horizontal plane is between 5° and 15°.

8. The shallow-water mooring system with a semi-tensioned band damper as described in claim 1, characterized in that, The pile foundations are symmetrically arranged around the floating structure, and the number of pile foundations is the same as the number of mooring assemblies. The number of mooring assemblies is 3 or 4. When there are 3 sets of mooring assemblies, the angle between the angle bisectors of the horizontal projections of the two outermost mooring cables in each set is 120°. When there are 4 sets of mooring assemblies, the angle between the angle bisectors of the horizontal projections of the two outermost mooring cables in each set is 90°.

9. The shallow-water mooring system with a semi-tensioned band damper as described in claim 1, characterized in that, The pile foundation is a cylindrical or polygonal long column with an outer diameter of 4000-6000 mm and a wall thickness of 40 mm-100 mm.

10. An installation method for connecting a shallow-to-medium water mooring system as described in any one of claims 1 to 9 to a floating structure, characterized in that, Includes the following steps: S1. Connect the lower end of the mooring cable of each set of mooring components to the pile foundation and the upper end to the float; S2. The mooring cables and pile foundations assembled in step S1 are towed to the designated machine location by barge. S3. Use a crane to lower the pile foundations to the predetermined machine site in sequence and drive the piles into the seabed. After reaching the predetermined depth, the pile driving operation is completed. The pile foundations are already connected to mooring cables. S3. The damping system platform for each set of the mooring components is installed on land; S4. Tow the floating structure to the predetermined landing site; S5. Remove the floats from the upper end of each mooring cable, hoist the upper end of the mooring cable to the damping system platform, use the traction rope to make the upper part of the mooring cable pass through the limit pile and the guide roller, and then connect the upper end of the mooring cable to the damper to complete the installation of a set of mooring components. S6. Repeat the above steps until all mooring components are connected to the floating structure. Apply pretension to the mooring cable by adjusting the damper and controlling the winch operation to complete the installation.

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