Anti-scouring structure for offshore wind power single pile foundation

Abstract

The invention relates to the technical field of offshore wind power engineering, in particular to an offshore wind power single-pile foundation anti-scouring structure which comprises a pile foundation, a rigid supporting frame, a wave reducing and flow controlling structure and a sediment blocking structure, and the rigid supporting frame comprises a circumferential supporting frame and axial supporting rods; the circumferential supporting frame is arranged around the pile foundation in a surrounding mode, and the circumferential supporting frame is provided with an upper layer and a lower layer. The axial supporting rods are fixedly arranged on the circumferential supporting frames, and the two layers of circumferential supporting frames are fixedly connected through the axial supporting rods. The wave reduction and flow control structure comprises a flexible cavity, a top composite membrane and a horizontal strip, and the flexible cavity is fixedly arranged in the rigid supporting frame; by absorbing wave energy, adverse flow states such as horseshoe vortexes and Karman vortexes are inhibited, and the hydrodynamic load borne by the foundation structure is remarkably reduced; meanwhile, the occurrence of scouring accidents is fundamentally reduced by weakening water flow at the bottom and blocking silt from moving.

Description

TECHNICAL FIELD

[0001] The present application relates to the offshore wind power engineering technical field, especially to a kind of offshore wind power single pile foundation scour protection structure. BACKGROUND

[0002] As an important part of clean energy, offshore wind power is served in complex marine environment for a long time, and continuously subjected to the scouring effect of wave, current and other hydrodynamic load. Especially on the pile foundation flow side, horseshoe vortex and karman vortex street are easily formed, which leads to the strong entrainment of seabed sediment around the pile, and further develops a deep scour pit. With the continuous intensification of scour, the effective embedded depth of pile foundation decreases, and the free length increases, which seriously weakens the bending bearing capacity and overall stability of the pile foundation, and even causes major safety accidents such as wind turbine tilt, tower fracture and collapse.

[0003] To alleviate the above scouring problem, traditional scour protection measures such as riprap and sand bag are often used in engineering. However, such methods are difficult to be precisely placed in the specified area around the pile, and there is a large gap between the pile foundation. Under the long-term action of water flow, the gap is easily eroded and hollowed out, which further expands the scour pit and threatens the stability of the pile foundation. In addition, the traditional measures lack effective regulation ability of the flow field around the pile, and are difficult to inhibit the formation of horseshoe vortex and karman vortex street, which cannot fundamentally prevent the continuous entrainment and loss of sediment, and the protection effect is limited. SUMMARY

[0004] Therefore, the present application provides an offshore wind power single pile foundation scour protection structure, which sets a rigid support frame composed of upper and lower two layers of circumferential support frame and axial support rod, and integrates a flexible cavity, a top composite film and a horizontal strip connecting the pile foundation and the frame to form a wave reduction and flow control structure, and configures a sediment blocking structure at the bottom, so as to cooperatively realize wave energy dissipation, suppression of adverse vortex around the pile, sealing of the gap at the top and blocking of sediment at the bottom, and effectively solve the technical problems of existing scour protection measures, such as local scour intensification due to poor adhesion and gap easy to be hollowed out, and lack of overall flow field regulation and stable protection ability.

[0005] The technical scheme of the present application is as follows: The present application provides an offshore wind power single pile foundation scour protection structure, which includes a pile foundation, a rigid support frame, a wave reduction and flow control structure, and a sediment blocking structure, wherein, The rigid support frame includes a circumferential support frame and an axial support rod, the circumferential support frame is arranged around the four sides of the pile foundation, and the circumferential support frame is provided with two layers; the axial support rod is fixedly arranged on the circumferential support frame, and the two layers of circumferential support frames are fixedly connected through the axial support rod; The wave-reducing flow control structure comprises a flexible cavity, a top composite film and a horizontal strip, the flexible cavity is fixedly arranged in the rigid support frame; the top composite film is fixedly arranged on the top side of the circumferential support frame, and the top side of the flexible cavity is arranged in a spaced manner with the top composite film; one end of the horizontal strip is fixedly arranged on the top side of the circumferential support frame, and the other end of the horizontal strip is fixedly arranged on the pile foundation. The silt blocking structure is fixedly arranged on the bottom side of the circumferential support frame.

[0006] On the basis of the above technical scheme, preferably, the circumferential support frame is two, symmetrically arranged on both sides of the pile foundation, wherein, The two circumferential support frames enclose a ring-shaped frame structure.

[0007] On the basis of the above technical scheme, preferably, the circumferential support frame comprises a circumferential frame rod and a radial support rod, wherein, The circumferential frame rod is arranged in multiple layers in the radial direction, and the multiple layers of circumferential frame rods are arranged coaxially; The radial support rod is arranged in multiple, and the multiple layers of circumferential frame rods are connected and combined into a semicircular frame structure through the multiple radial support rods.

[0008] On the basis of the above technical scheme, preferably, the flexible cavity is arranged in the interspace between the circumferential frame rod and the radial support rod, the flexible cavity comprises an axial flexible film and a circumferential flexible film, wherein, The axial flexible film and the circumferential flexible film are both fixedly arranged on the axial support rod, and the axial flexible film and the circumferential flexible film are connected end to end to form an upper and lower hollow cavity structure.

[0009] On the basis of the above technical scheme, preferably, the silt blocking structure comprises a bottom composite film and a bottom film cover blanket, wherein, The bottom composite film is fixedly arranged on the bottom side of the circumferential support frame, and the bottom composite film is arranged in a spaced manner with the flexible cavity; The bottom film cover blanket is laid on the bottom composite film.

[0010] On the basis of the above technical scheme, preferably, the bottom composite film is annular as a whole, and the bottom composite film is arranged in multiple layers, wherein, The multiple layers of bottom composite films are arranged coaxially, and the adjacent two layers of bottom composite films are fixedly connected at the joint.

[0011] On the basis of the above technical scheme, preferably, it further comprises a stabilizing structure, the stabilizing structure comprises a bottom support frame, a side composite film and a side film cover blanket, wherein, The bottom support frame is fixedly arranged on the outer side of the circumferential support frame; The side composite film is fixedly arranged on the top side of the bottom support frame; The side film cover is laid on the side composite film.

[0012] On the basis of the above technical scheme, preferably, the bottom support frame comprises a radial outer support rod and a circumferential support rod, wherein, One end of the radial outer support rod is fixedly arranged on the circumferential support frame; The circumferential support rod is fixedly arranged on the other end of the radial outer support rod, and the radial span of the circumferential support rod is greater than that of the circumferential support frame, and the height of the circumferential support rod is lower than that of the circumferential support frame.

[0013] On the basis of the above technical scheme, preferably, a plurality of horizontal strips are arranged on the circumferential support frame, and the horizontal strips are arranged at intervals along the surface of the pile foundation, and the side edges of adjacent horizontal strips are in close contact with each other.

[0014] On the basis of the above technical scheme, preferably, a plurality of cutting seams are arranged on the surface of the horizontal strip.

[0015] The offshore wind power single pile foundation scour prevention structure of the present application has the following advantages over the prior art: (1) By arranging a rigid support frame composed of two layers of circumferential support frames and axial support rods, and integrating a flexible cavity, a top composite film and a horizontal strip connecting the pile foundation and the frame inside the frame to form a wave reduction and flow control structure, and configuring a sediment blocking structure at the bottom, the multi-dimensional collaborative protection of wave energy dissipation, suppression of adverse eddy around the pile, top annular gap sealing and bottom sediment sealing is realized. This not only improves the structural stability of the device in complex marine environment, but also blocks the scouring mechanism from the source, effectively prevents the sea bed sediment around the pile foundation from being carried away by the water flow, and thus realizes efficient and systematic prevention and control of the scouring problem of offshore wind power single pile foundation.

[0016] (2) By arranging a plurality of cutting seams on the surface of the horizontal strip, a flexible interface with microporous characteristics is formed, which allows a small amount of water to slowly penetrate while maintaining the sediment blocking effect, balances the water pressure inside and outside the device, and thus reduces the risk of swelling, tearing or fatigue damage of the flexible membrane structure due to pressure sudden change, and improves the durability and long-term service life of the device.

[0017] (3) By arranging the flexible cavity to be formed by the axial flexible membrane and the circumferential flexible membrane surrounding the cavity structure in the gap of the frame, the wave energy can be dissipated by the resonance of the water column in the cavity and the vibration of the membrane body, and the incident wave intensity can be weakened by multiple reflections. At the same time, the open design allows water to enter the cavity in an orderly manner to form multi-directional vortexes, which can destroy the high-speed low-pressure area and periodic vortex shedding of the external flow, effectively reduce the fluctuating pressure gradient of the flow field, reduce the stress on the device itself and suppress the peripheral scouring.

[0018] (4) The top side of the flexible cavity is spaced apart from the top composite film, and the bottom side is spaced apart from the bottom composite film, forming a water flow channel that penetrates up and down. Water flow can enter the interior of the device through these gaps and flow in the flexible cavity, breaking the traditional single-direction flow around the pile, dispersing the high-speed low-pressure area and Karman vortex street pulsation area that were originally concentrated on the outer edge of the structure, and making the flow field pressure distribution tend to be uniform and stable, thereby effectively inhibiting the external seabed sediment from being scoured by the entrainment. At the same time, the downward pressure difference force generated by the water flow in the cavity, combined with the hydrostatic pressure and the seabed negative pressure suction, jointly acts on the device as a whole, significantly improving its anti-floating, anti-sliding and anti-overturning ability, and ensuring the long-term stable bottom state of the structure in complex marine environment.

[0019] (5) By setting the circumferential support rod of the bottom support frame to be lower than the main body frame and embedded in the seabed sediment, cooperating with the side composite film and the side membrane cover blanket that is immersed and solidified on it, the water inlet channel at the bottom edge of the device is effectively blocked, and under the combined action of deep water static pressure, gravity and seabed negative pressure suction, a multiple anti-overturning and anti-sliding mechanism is formed to ensure the long-term stable adhesion of the device to the seabed. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, a brief introduction will be given below to the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0021] Figure 1 It is a perspective view of a seabed scouring prevention structure of a single pile foundation of offshore wind power; Figure 2 It is a perspective view of a wave reduction and flow control structure in a seabed scouring prevention structure of a single pile foundation of offshore wind power; Figure 3 It is an explosion view of a flexible cavity in a seabed scouring prevention structure of a single pile foundation of offshore wind power; Figure 4 It is a structural schematic view of a rigid support frame in a seabed scouring prevention structure of a single pile foundation of offshore wind power; Figure 5 It is a perspective view of a circumferential support frame in a seabed scouring prevention structure of a single pile foundation of offshore wind power; Figure 6 It is a perspective view of a sediment blocking structure in a seabed scouring prevention structure of a single pile foundation of offshore wind power; Figure 7 It is a perspective view of a bottom support frame in a seabed scouring prevention structure of a single pile foundation of offshore wind power; In the figure: 1, pile foundation; 2, rigid support frame; 3, wave-reducing and flow-controlling structure; 4, sediment-blocking structure; 5, stabilizing structure; 21, circumferential support frame; 22, axial support rod; 31, flexible cavity; 32, top composite membrane; 33, horizontal strip; 41, bottom composite membrane; 42, bottom membrane cover; 51, bottom support frame; 52, side composite membrane; 53, side membrane cover; 211, circumferential frame rod; 212, radial support rod; 311, axial flexible membrane; 312, circumferential flexible membrane; 511, radial outer support rod; 512, circumferential support rod. DETAILED DESCRIPTION

[0022] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions in the present application will be clearly and completely described below with reference to the drawings in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0023] In the description of the embodiments of the present application, it should be noted that unless specifically defined and limited, the terms "connected", "connected" should be understood in a broad sense, for example, can be fixedly connected, can also be detachably connected, or integrally connected; can be mechanically connected, can also be electrically connected; can be directly connected, or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0024] In the description of the embodiments of the present application, it should be noted that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the embodiments of the present application.

[0025] In addition, the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0026] Embodiments of the present application are described in detail below with reference to the attached drawing figures, wherein like or similar constituent elements or features may be denoted by like reference characters throughout the drawing figures and text. The embodiments described below are exemplary in nature and are intended to be illustrative of the present application rather than to limit the same.

[0027] The disclosure that follows provides many different embodiments, or examples, for implementing different structures of the present application. For the purpose of simplicity, the elements and settings of the various examples are described in the following disclosure. Of course, they are merely examples and are intended to be illustrative of the application and not limiting of the same. Furthermore, the application can be used in different examples with varying and / or different elements than those described. Such variations and / or modifications are within the scope and spirit of the application. In addition, the various embodiments of the present application are described in the following disclosure with reference to a number and / or letter of reference characters to illustrate preferred aspects in a convenient and efficient manner. Such references characters equally apply to similar elements and / or settings throughout the various embodiments and / or instances of the present application, as appropriate. Such references characters are intended to simplify the present disclosure and are not intended in any way to limit the scope of the application.

[0028] As shown in the drawings, Figures 1 to 7 A scouring prevention structure of a monopile foundation of offshore wind power, according to the present application, comprises a pile foundation 1, a rigid support frame 2, a wave-damping and flow-controlling structure 3, a sediment-blocking structure 4 and a stabilizing structure 5.

[0029] The pile foundation 1 is a monopile foundation of offshore wind power facilities, vertically driven into seabed and subjected to wave and current scouring.

[0030] The rigid support frame 2, as the support skeleton of the whole device, is made of high-density polyethylene (HDPE) pipe material, with high strength, corrosion resistance and lightweight characteristics. The frame is divided into two symmetrical half-ring parts, which can be prefabricated onshore, transported separately, and installed around the pile foundation 1 under water. The frame includes a circumferential support frame 21 and an axial support rod 22.

[0031] The circumferential support frame 21 is symmetrically arranged on both sides of the pile foundation 1, and the two circumferential support frames 21 form a ring frame structure. The circumferential support frame 21 is arranged in two layers, which are parallel to each other and connected by the vertical axial support rod 22, providing stable support for the overall structure.

[0032] Further, the circumferential support frame 21 comprises circumferential frame rods 211 and radial support rods 212. Among them, the circumferential frame rods 211 are arranged coaxially in multiple layers from inside to outside in the radial direction. And the radial support rods 212 are arranged between the adjacent two layers of circumferential frame rods 211 for connection between them. The number of radial support rods 212 is determined according to the arc length of the circumferential frame rods 211, and the radial support rods 212 are arranged uniformly. The multiple layers of circumferential frame rods 211 are connected and combined into a semicircular frame structure through multiple radial support rods 212, enhancing the rigidity and stability of the overall structure.

[0033] The wave reduction and flow control structure 3 is arranged inside the rigid support frame 2, for weakening wave energy, regulating the flow field around the pile, and suppressing adverse vortices. It comprises a flexible cavity 31, a top composite film 32, and a horizontal strip 33.

[0034] Among them, the flexible cavity 31 is fixedly arranged in the rigid support frame 2, specifically in multiple gaps between the circumferential frame rods 211 and the radial support rods 212. The flexible cavity 31 comprises an axial flexible film 311 and a circumferential flexible film 312, both of which are HDPE composite films. The edges of the axial flexible film 311 and the circumferential flexible film 312 are fixed on the axial support rods 22, and are connected end to end in each gap to form a cavity structure with upper and lower openings. The top composite film 32 is fixedly arranged on the top side of the circumferential support frame 21, and is also an HDPE composite film.

[0035] This structure can utilize the resonance of water column in the cavity and the vibration of the film to cooperatively dissipate wave energy, and weaken the incident wave intensity through multiple reflections. At the same time, the open design allows water flow to enter the cavity in an orderly manner to form multi-directional vortices, which can destroy the high-speed low-pressure area of the external flow and the periodic vortex shedding of the Karman vortex street, effectively reducing the fluctuating pressure gradient of the flow field. At the same time, the top composite film 32 also blocks the path of the upward loss of seabed sediment, ensuring that there is enough sediment protection at the bottom of the pile foundation 1.

[0036] The horizontal strip 33 is a fan-shaped piece structure, arranged in a top annular gap between the pile foundation 1 and the circumferential support frame 21 in a circumferential direction, fixed to the top side of the circumferential support frame 21 at one end, and anchored to the surface of the pile foundation 1 at the other end, with the side edges of adjacent horizontal strips 33 abutting each other. The horizontal strip 33 can effectively hinder the high-speed jet flow along the pile wall, eliminate the generation conditions of the horseshoe vortex, and actively suppress the source of pile foot scouring. At the same time, the horizontal strip 33 also blocks the path of the upward loss of seabed sediment along the surface of the pile foundation 1, ensuring that there is enough sediment protection at the bottom of the pile foundation 1.

[0037] Further, each horizontal strip 33 is provided with a plurality of parallel cutting seams on the strip surface, forming a microporous flexible interface that allows a small amount of water to slowly penetrate while effectively blocking the upward migration of large particles of sediment, thereby balancing the water pressure inside and outside the device, avoiding the accumulation of abnormal positive or negative pressure inside due to sealing, reducing the risk of flexible membrane swelling, tearing or fatigue damage, and prolonging the service life.

[0038] The sediment barrier structure 4 is arranged at the bottom of the rigid support frame 2 and is used to physically cut off the direct contact between the water flow and the seabed sediment, which includes a bottom composite membrane 41 and a bottom membrane cover 42.

[0039] The bottom composite membrane 41 is made of HDPE composite membrane and has a ring shape and is fixed to the bottom side of the circumferential support frame 21. It is provided with a plurality of coaxial annular membrane sheets in the radial direction, and the adjacent membrane sheets are sealed and fixed by thermoplastic welding. After installation, the bottom composite membrane 41 is tightly laid on the seabed, ensuring that the coverage is sufficient and there is no leakage channel, so as to completely seal the sediment around the pile foundation 1 below the device.

[0040] The bottom membrane cover 42 is laid on the bottom composite membrane 41 and is made of cement blanket material. It is light and easy to transport and install in dry state, and solidifies and increases weight after being soaked in water for 24 hours, and tightly presses the bottom composite membrane 41 against the seabed by its own weight, effectively inhibiting the membrane body from shaking and the edge from being lifted, and significantly improving the long-term service reliability.

[0041] In the above structure, the top side of the flexible cavity 31 is spaced apart from the top composite membrane 32, and the bottom side of the flexible cavity 31 is also spaced apart from the bottom composite membrane 41, so that the flexible cavity 31 and the top composite membrane 32 and the bottom composite membrane 41 leave a gap to form a water flow channel. The water flow enters the inside of the device through the gap and flows in the flexible cavity 31, breaking the traditional single-direction flow around the pile, so that the high-speed low-pressure area of the cylindrical flow originally concentrated on the outer edge of the structure and the Karman vortex street pulsation area can be dissipated, and the pressure distribution of the flow field tends to be uniform and stable, thereby effectively inhibiting the external seabed sediment from being entrained and washed away. At the same time, the downward pressure difference generated by the water flow in the cavity, combined with the deep water static pressure and the seabed negative pressure suction, acts on the whole device, significantly improving its anti-floating, anti-sliding and anti-overturning ability.

[0042] The stabilizing structure 5 is arranged outside the rigid support frame 2 and is used to further enhance the stability of the bottom of the device. It includes a bottom support frame 51, a side composite membrane 52 and a side membrane cover 53.

[0043] The bottom support frame 51 is fixedly arranged outside the circumferential support frame 21 and comprises a radial outer support rod 511 and a circumferential support rod 512. One end of the radial outer support rod 511 is fixedly arranged on the circumferential support frame 21, and the circumferential support rod 512 is fixedly arranged at the other end of the radial outer support rod 511. The radial span of the circumferential support rod 512 is greater than that of the circumferential support frame 21, and the height of the circumferential support rod 512 is lower than that of the circumferential support frame 21, so that the circumferential support rod 512 can be embedded in the seabed silt, effectively blocking the water inlet channel at the bottom edge of the device, and preventing the water flow from flowing into the lower part of the device to cause hollowing or suction instability.

[0044] The side composite film 52 is fixedly arranged on the top side of the bottom support frame 51 and is made of an HDPE composite film. The side film cover 53 is laid on the side composite film 52, and the side film cover 53 is made of the same material as the bottom film cover 42. Under the combined action of deep water static pressure, gravity and seabed negative pressure suction, the two form a multiple anti-overturning and anti-sliding mechanism to ensure the long-term stability of the device adhering to the seabed.

[0045] It should be noted that the above-mentioned HDPE composite film can select different types of composite film materials according to the functional requirements of the position of the anti-erosion structure to achieve the optimal matching of performance and durability.

[0046] The flexible cavity 31 can be made of an HDPE / LLDPE co-extruded film (thickness 0.8-1.2 mm). Since it needs to vibrate repeatedly under the action of waves to dissipate energy, the material is required to have excellent flexibility, fatigue resistance and dynamic deformation ability.

[0047] The top composite film 32, the bottom composite film 41 and the side composite film 52 can adopt a two-cloth-one-film type HDPE composite geomembrane (HDPE film thickness≥1.0 mm, two sides of non-woven geotextile unit area mass≥200 g / m²). This structure has high impermeability of the HDPE film and the anti-puncture, anti-sliding and interface friction performance of the geotextile, which is convenient for underwater laying and can realize reliable sealing through hot melt welding.

[0048] The horizontal strip 33 can adopt a single-layer HDPE film or an HDPE and geotextile composite strip. While ensuring a certain rigidity to maintain the annular sealing shape, the micro-porous structure allows slow water permeation, effectively balances the internal and external water pressure, and prevents bulging damage.

[0049] Based on the above-mentioned anti-erosion structure of the offshore wind power single pile foundation, the application provides a use method of the anti-erosion structure of the offshore wind power single pile foundation, which is as follows: First step, shore prefabrication of support frame and accessory structure: first, cut the high-density polyethylene (HDPE) pipe on the shore to make the circumferential frame rod 211, the radial support rod 212, the axial support rod 22, and the radial outer support rod 511 and the circumferential support rod 512 in the stabilizing structure 5; through the thermoplastic welding process, the circumferential frame rod 211 and the radial support rod 212 are assembled into two layers of semicircular circumferential support frames 21; then the upper and lower two layers are fixedly connected through the axial support rod 22 to form a semicircular main skeleton with three-dimensional rigidity; at the same time, the radial outer support rod 511 is welded at one end to the outside of the circumferential support frame 21, and the other end is connected to the circumferential support rod 512 to complete the assembly of the bottom support frame 51; wherein the installation height of the circumferential support rod 512 is lower than that of the circumferential support frame 21, so as to ensure that it can be embedded in the seabed in the subsequent step.

[0050] Second step, installation of flexible membrane assembly and cover blanket: cut the HDPE composite membrane into axial flexible membrane 311 and circumferential flexible membrane 312 of the designed size, and fix them on the axial support rod 22 through thermoplastic welding, and surround them in the gap between the circumferential frame rod 211 and the radial support rod 212 to form an upper and lower transparent flexible cavity 31; lay and fix the top composite membrane 32 on the top side of the circumferential support frame 21, and make sure that it is kept at a set interval from the top side of the flexible cavity 31; lay and fix the bottom composite membrane 41 on the bottom side of the circumferential support frame 21, and seal the joint of the multi-layer annular membrane sheet through thermoplastic welding; cover the side composite membrane 52 on the top side of the bottom support frame 51; then, lay the bottom membrane cover blanket 42 on the bottom composite membrane 41, and lay the side membrane cover blanket 53 on the side composite membrane 52; the membrane cover blanket is preferably a cement blanket, which is light in dry state and convenient for transportation and laying.

[0051] Third step, installation of strip: arrange the horizontal strip 33 provided with parallel cutting seams in the top annular gap area between the pile foundation 1 and the circumferential support frame 21 in the circumferential direction, one end of which is fixed to the top side of the circumferential support frame 21 through thermoplastic welding or mechanical clamp, and the other end is temporarily freely extended.

[0052] Fourth step, offshore hoisting and closing: use the offshore crane ship to hoist the two semicircular rigid support frames 2 with completed membrane covering and accessory installation from both sides of the pile foundation 1 simultaneously, and slowly lower them to the predetermined seabed position; when the circumferential support rod 512 of the bottom support frame 51 is embedded in the seabed sediment, use the underwater ROV to assist, and use special connecting pieces (such as bolt flanges, clamps or locking buckles) to firmly connect the two semicircles at the joint to form a complete annular anti-scour device; then, fasten the horizontal strip 33 to the surface of the pile foundation 1 through the clamp or clamp, and make sure that the end close to the pile foundation 1 is slightly higher than the outside after installation to guide the water flow direction and enhance the annular gap sealing effect.

[0053] In the fifth step, the system is in place and functional: after the device is in place, the bottom membrane cover blanket 42 and the side membrane cover blanket 53 gradually solidify and increase in weight under seawater immersion, thereby tightly pressing the bottom composite membrane 41 and the side composite membrane 52 to the seabed; water flows through the gap between the top and the bottom into the flexible cavity 31, forming a multi-directional vortex to achieve wave reduction and flow control; the horizontal strip 33 cooperates with the silt blocking structure 4 to effectively block the silt migration path, and the whole system enters a long-term stable protection state.

[0054] It should be noted that the present application is not only suitable for offshore wind power single pile foundation, but also can be popularized and applied to bridge pier column, wharf pile foundation, trestle support or fixed offshore platform and other types of seabed driven pile column structures for anti-scour protection.

[0055] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A scour protection structure for a monopile foundation of an offshore wind turbine, characterized in that: It comprises a pile foundation (1), a rigid support frame (2), a wave-reducing and flow-controlling structure (3) and a sediment-blocking structure (4), wherein, The rigid support frame (2) comprises a circumferential support frame (21) and an axial support rod (22), the circumferential support frame (21) is arranged around the four sides of the pile foundation (1), and the circumferential support frame (21) is provided with two layers of upper and lower layers; the axial support rod (22) is fixedly arranged on the circumferential support frame (21), and the two layers of circumferential support frames (21) are fixedly connected through the axial support rod (22); The wave-reducing and flow-controlling structure (3) comprises a flexible cavity (31), a top composite film (32) and a horizontal strip (33), the flexible cavity (31) is fixedly arranged in the rigid support frame (2); the top composite film (32) is fixedly arranged on the top side of the circumferential support frame (21), and the top side of the flexible cavity (31) is arranged in a spaced manner with the top composite film (32); one end of the horizontal strip (33) is fixedly arranged on the top side of the circumferential support frame (21), and the other end of the horizontal strip (33) is fixedly arranged on the pile foundation (1); The sediment-blocking structure (4) is fixedly arranged on the bottom side of the circumferential support frame (21).

2. A scour protection structure for a monopile foundation of an offshore wind turbine according to claim 1, characterized in that: The circumferential support frame (21) is two, symmetrically arranged on both sides of the pile foundation (1), wherein, The two circumferential support frames (21) enclose a ring-shaped frame structure.

3. A scour protection structure for a monopile foundation of an offshore wind turbine according to claim 1, characterized in that: The circumferential support frame (21) comprises a circumferential frame rod (211) and a radial support rod (212), wherein, The circumferential frame rod (211) is provided with multiple layers in the radial direction, and the multiple layers of circumferential frame rods (211) are arranged coaxially; The radial support rod (212) is provided with multiple, and the multiple layers of circumferential frame rods (211) are connected and combined into a semicircular frame structure through the multiple radial support rods (212).

4. A scour protection structure for a monopile foundation of an offshore wind turbine according to claim 3, characterized in that: The flexible cavity (31) is arranged in the interspace between the circumferential frame rod (211) and the radial support rod (212), and the flexible cavity (31) comprises an axial flexible film (311) and a circumferential flexible film (312), wherein, The axial flexible film (311) and the circumferential flexible film (312) are both fixedly arranged on the axial support rod (22), and the axial flexible film (311) and the circumferential flexible film (312) are connected head to tail to form an upper and lower hollow cavity structure.

5. A scour protection structure for a monopile foundation of an offshore wind turbine according to claim 1, characterized in that: The sediment-blocking structure (4) comprises a bottom composite film (41) and a bottom film cover blanket (42), wherein, The bottom composite film (41) is fixedly arranged on the bottom side of the circumferential support frame (21), and the bottom composite film (41) is arranged in a spaced manner with the flexible cavity (31); The bottom film cover blanket (42) is laid on the bottom composite film (41).

6. A scour protection structure for an offshore wind monopile foundation according to claim 5, characterized in that: The bottom composite film (41) is annular as a whole, and the bottom composite film (41) is provided with multiple layers, wherein, The multiple layers of bottom composite films (41) are arranged coaxially, and the abutting portions of adjacent two layers of bottom composite films (41) are fixedly connected.

7. A scour protection structure for a monopile foundation of an offshore wind turbine according to claim 1, characterized in that: Further comprising a stabilizing structure (5) comprising a bottom support frame (51), a side composite film (52) and a side film cover blanket (53), wherein, The bottom support frame (51) is fixedly arranged on the outer side of the circumferential support frame (21); The side composite film (52) is fixedly arranged on the top side of the bottom support frame (51); The side film cover blanket (53) is laid on the side composite film (52).

8. A scour protection structure for a monopile foundation of an offshore wind turbine according to claim 7, characterized in that: The bottom support frame (51) comprises a radial outer support rod (511) and a circumferential support rod (512), wherein, One end of the radial outer support rod (511) is fixedly arranged on the circumferential support frame (21); The circumferential support rod (512) is fixedly arranged on the other end of the radial outer support rod (511), and the radial span of the circumferential support rod (512) is greater than that of the circumferential support frame (21), and the height of the circumferential support rod (512) is lower than that of the circumferential support frame (21).

9. A scour protection structure for a monopile foundation of an offshore wind turbine according to claim 1, characterized in that: A plurality of horizontal strips (33) are arranged on the circumferential support frame (21), and the plurality of horizontal strips (33) are arranged at intervals along the surface of the pile foundation (1), and the side edges of adjacent horizontal strips (33) are in contact with each other.

10. A scour protection structure for a monopile foundation of an offshore wind turbine according to claim 1, characterized in that: A plurality of cutting seams are arranged on the surface of the horizontal strip (33).

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