A device for protecting offshore wind turbine pile foundations from scour caused by reciprocating flow.

Abstract

This invention belongs to the field of marine engineering technology, and particularly relates to a device for protecting offshore wind turbine pile foundations from scour in reciprocating currents. The device includes a breakwater base; a breakwater core, set on the breakwater base, with a trapezoidal cross-section; a seaward slope, laid on the seaward side of the breakwater core, comprising a sedimentation zone, a sediment collection platform, and an erosion prevention zone from top to bottom; a leeward slope, laid on the seaward side of the breakwater core, with a slope of 1:1.5 to 1:3; and a breakwater crest, located at the top of the breakwater core, with a triangular cross-section, the width gradually increasing from the top downwards, and its bottom abutting against the top of the sedimentation zone, the top of the breakwater core, and the top of the leeward slope, respectively. The sedimentation zone is located at the top of the seaward slope with a slope of 1:1.5 to 1:3; the erosion prevention zone is located at the bottom of the seaward slope, abutting against the breakwater base, with a slope of 1:1 to 1:1.5; and the sediment collection platform is located between the sedimentation zone and the erosion prevention zone, with a width 1.5 to 3 times the width of the breakwater core, connecting the sedimentation zone and the erosion prevention zone.

Description

Technical Field

[0001] This invention belongs to the field of marine engineering technology, specifically relating to a device for protecting offshore wind turbine pile foundations from scour caused by reciprocating currents and human-shaped submerged breakwaters. Background Technology

[0002] With the rapid development of offshore wind power, the safety and stability of wind turbine foundations have become critical issues. Offshore wind turbine foundations are located underwater and are susceptible to erosion from water currents and waves, leading to the loss of sediment around the foundations, forming scour pits, which in turn affect the stability of the foundations and may even cause them to fail. Summary of the Invention

[0003] This invention overcomes the shortcomings of the prior art and provides a device for protecting offshore wind turbine pile foundations from scour caused by reciprocating flow.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is: a device for protecting offshore wind turbine pile foundations from scour caused by reciprocating currents, comprising:

[0005] Embankment foundation;

[0006] The core of the dike is located on the dike foundation and has a trapezoidal cross-section.

[0007] The seaward slope, laid on the ocean-facing side of the breakwater, includes, from top to bottom, a sedimentation zone, a sediment collection platform, and an erosion protection zone. The sedimentation zone is located at the top of the seaward slope with a slope of 1:1.5 to 1:3. The erosion protection zone is located at the bottom of the seaward slope, where the bottom meets the breakwater foundation, with a slope of 1:1 to 1:1.5. The sediment collection platform is located between the sedimentation zone and the erosion protection zone, connecting the two areas.

[0008] The seaward slope is laid on the side of the breakwater away from the ocean, with a slope of 1:1.5 to 1:3.

[0009] The top of the dike is located at the top of the dike core. It has a triangular cross-section, with the width gradually increasing from the top downwards. Its bottom abuts against the top of the sedimentation zone, the top of the dike core, and the top of the back slope, respectively.

[0010] In a preferred embodiment of the present invention, the width of the sediment collection platform is 1.5 to 3 times the width of the dike core.

[0011] In a preferred embodiment of the present invention, diversion channels are provided at intervals on the surface of the deposition zone; each diversion channel is provided at intervals along the slope direction of the deposition zone, including a main channel and branch channels extending from the center of the main channel to both sides.

[0012] In a preferred embodiment of the present invention, a grid guide plate is provided at the connection between the sedimentation zone and the sediment collection platform; the grid guide plate is composed of intersecting strip structures, and the strip structures form a grid with a aperture of 20-40 cm.

[0013] In a preferred embodiment of the present invention, a retention layer is laid on the surface of the sediment collection platform; the retention layer includes one or more of a basalt gravel layer and a high-density polyethylene mesh pad; wherein the particle size of the basalt gravel layer is 5-20 cm and the thickness is 10-30 cm; the pore size of the high-density polyethylene mesh pad is 10-20 cm and the thickness is 5-15 cm.

[0014] In a preferred embodiment of the present invention, recessed areas are provided at intervals on the surface of the sediment collection platform; the recessed areas are shallow saucer-shaped, with a depth of 0-10cm, a diameter of 20-30cm, and a spacing of 50-80cm.

[0015] In a preferred embodiment of the present invention, biomimetic grass is laid on the surface of the back slope.

[0016] In a preferred embodiment of the present invention, a riprap cushion layer is provided between the core of the dike and the seaward slope, and between the core of the dike and the back slope.

[0017] In a preferred embodiment of the present invention, the core of the dike further includes a set of bottom protection; the bottom protection has a parallelogram cross section and a thickness of 0.6 to 1.2 m, and is respectively set on the dike foundation on both sides of the core of the dike, abutting against the outer edges of the seaward slope and the back slope; wherein, the bottom protection abutting against the seaward slope is the seaside bottom protection, with a width of 6 to 10 m; and the bottom protection abutting against the back slope is the shoreside bottom protection, with a width of 4 to 6 m.

[0018] In a preferred embodiment of the present invention, the core of the dike also includes a set of prisms; the prisms are prismatic structures with parallelogram cross sections, and the long side is fixed to the upper surface of the bottom protection (22) parallel to the direction of the core of the dike, respectively abutting against the sea-facing slope and the back slope; the top surface of the prisms is 2-4m wide and 2-4m thick.

[0019] This invention addresses the shortcomings of the prior art and has the following beneficial effects:

[0020] This invention optimizes the submerged breakwater structure, effectively improving sediment retention rate and significantly reducing the extent and maximum scour depth of scour pits, thereby better protecting offshore wind turbine foundations from scour and improving the stability and safety of the foundations.

[0021] This invention provides a scour protection device for offshore wind turbine foundations using a reciprocating submerged breakwater, comprising a breakwater base, a trapezoidal breakwater core on the base, a seaward slope on the seaward side of the breakwater core, a shore-facing slope on the shore-facing side of the breakwater core, and a breakwater crest at the top of the breakwater core. The seaward slope is divided into a sedimentation zone, a sediment collection platform, and an erosion protection zone from top to bottom. The sedimentation zone slows the water flow, promoting sediment settling. The sediment collection platform, 1.5 to 3 times the width of the breakwater core, provides space for sediment accumulation. The erosion protection zone protects the bottom of the submerged breakwater from direct scour. Compared to simple riprap or slope protection, this invention can more effectively intercept and retain sediment, thereby more effectively preventing scour, reducing the amount of sediment reaching the wind turbine foundation, and decreasing the depth and extent of scour.

[0022] This invention provides a scour protection device for offshore wind turbine pile foundations with a reciprocating flow-shaped submerged breakwater. The device comprises diversion channels, including a main channel and branch channels extending from the center of the main channel to both sides, spaced at intervals on the surface of the sedimentation zone. A grid guide plate is installed at the connection between the sedimentation zone and the sediment collection platform. A retention layer and recessed areas are laid on the surface of the sediment collection platform, and biomimetic grass is laid on the surface of the leeward slope. The diversion channels guide the water flow, changing the flow path and velocity, thus reducing the scour force on the sediment. The grid guide plate intercepts some larger sediment particles, reducing the amount of sediment reaching the downstream. The retention layer increases surface roughness and porosity, improving the friction of the sediment. The recessed areas create additional sediment accumulation areas. The biomimetic grass increases the surface roughness of the leeward slope, reducing the flow velocity on the leeward slope. Compared to traditional scour prevention measures, this invention can more effectively slow down the water flow velocity, intercept and retain sediment, significantly improve the sediment retention rate, and effectively reduce the range and maximum scour depth of the scour pit.

[0023] This invention forms an active interception and retention system for sediments by setting up a sedimentation zone, a sediment collection platform, and an anti-erosion zone. On this basis, diversion channels, grid guide plates, retention layers, depression areas, and biomimetic grass are added to increase the roughness and porosity of the sediment collection platform, improve the friction of sediments, increase the sediment accumulation area, increase the roughness of the back slope surface, and reduce the flow velocity on the back slope, thereby further improving the sediment retention rate, significantly reducing the amount of silt reaching the wind turbine foundation, and reducing the depth and extent of scour. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the structure of a reciprocating flow-driven human-shaped submerged breakwater offshore wind turbine pile foundation scour protection device provided by the present invention;

[0026] Figure 2 This is a schematic diagram of the structure of the sea-facing slope;

[0027] In the diagram: 1. Dike base; 2. Dike core; 3. Seaward slope; 4. Backward slope; 5. Dike crest; 21. Subbase; 22. Bottom protection; 23. Prism; 31. Sedimentation zone; 32. Sediment collection platform; 33. Erosion protection zone; 34. Diversion channel; 35. Grating guide plate; 36. Retention layer; 37. Depression area; 44. Bionic grass; 341. Main channel; 342. Branch channel. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein. Therefore, the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0030] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the scope of protection of this application. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0031] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art will understand the specific meaning of the above terms in this application based on the specific circumstances.

[0032] Exemplary device:

[0033] like Figure 1 , Figure 2 As shown, a device for protecting offshore wind turbine pile foundations from scour caused by reciprocating currents and human-shaped submersible breakwaters includes:

[0034] Embankment 1.

[0035] Embankment core 2 is located on embankment foundation 1 and has a trapezoidal cross-section.

[0036] The seaward slope 3, laid on the ocean-facing side of the core 2, comprises, from top to bottom, a sedimentation zone 31, a sediment collection platform 32, and an erosion protection zone 33. The sedimentation zone 31 is located at the top of the seaward slope 3, with a slope of 1:1.5 to 1:3. The erosion protection zone 33 is located at the bottom of the seaward slope 3, abutting against the foundation 1, with a slope of 1:1 to 1:1.5. The sediment collection platform 32 connects the sedimentation zone 31 and the erosion protection zone 33.

[0037] The seaward slope 4 is laid on the side of the dike core 2 away from the sea, with a slope of 1:1.5 to 1:3.

[0038] The top of the dike 5 is located at the top of the core of the dike 2. It has a triangular cross-section and its width gradually increases from the top down. Its bottom is connected to the top of the sedimentation zone 31, the top of the core of the dike 2, and the back slope 4, respectively, and its top is connected to each other.

[0039] In one specific embodiment, the dike base 1 is constructed of cast concrete with a compressive strength greater than or equal to C40 and an average thickness of 2m. The dike core 2 is constructed of natural boulders with a maximum particle size of 1.2m, laid in layers and compacted, with a cross-section approximately an isosceles trapezoid with a top width of 3m, a bottom width of 12m, and a height of 3m. The seaward slope 3 is constructed of cast high-strength concrete with a compressive strength greater than or equal to C50 and an average thickness of 1.2m. The seaward slope 4 is constructed of cast high-strength concrete with a compressive strength greater than or equal to C40 and an average thickness of 1.0m. The dike crest 5 is constructed of natural boulders with a maximum particle size of 1.5m, laid in layers and compacted, and grouted with cement mortar, with a cross-section approximately triangular.

[0040] like Figure 1As shown, a stone cushion layer 21 is provided between the core 2 and the seaward slope 3, and between the core 2 and the back slope 4.

[0041] In one specific embodiment, the rubble cushion layer 21 is made of natural rubble with a maximum rubble diameter of 0.6m, which is laid in layers, compacted, and grouted with cement mortar, with an average thickness of 1m.

[0042] It should be noted that the width of the sediment collection platform 32 is 1.5 to 3 times the width of the dike core 2.

[0043] In one specific embodiment, the cross-section of the core 2 is 3m wide at the top, 12m wide at the bottom, and 3m high. The average thickness of the sedimentation zone 31 and the erosion prevention zone 33 is 1.2m. The width of the sediment collection platform 32 is twice the width of the core 2.

[0044] like Figure 2 As shown, diversion channels 34 are spaced apart on the surface of the sedimentation zone 31. Each diversion channel 34 is spaced apart along the slope of the sedimentation zone 31, including a main channel 341 and branch channels 342 extending from the center of the main channel 341 to both sides. The cross-sections of the main channel 341 and the branch channels 342 are both arc-shaped.

[0045] like Figure 2 As shown, a grid guide plate 35 is installed at the connection between the sedimentation zone 31 and the sediment collection platform 32. The grid guide plate 35 is composed of intersecting strip structures, forming cells with an aperture of 20-40 cm between the strip structures. The strip structures can be made of alloy materials with sufficient strength, corrosion resistance, and erosion resistance, such as steel plates or structural steel.

[0046] like Figure 2 As shown, a retention layer 36 is laid on the surface of the sediment collection platform 32. The retention layer 36 includes one or more of a basalt gravel layer and a high-density polyethylene mesh mat. The basalt gravel layer has a particle size of 5–20 cm and a thickness of 10–30 cm. The high-density polyethylene mesh mat has a pore size of 10–20 cm and a thickness of 5–15 cm.

[0047] In one specific embodiment, a basalt gravel layer with a thickness of 20 cm is laid on the surface of the sediment collection platform 32, and a high-density polyethylene mesh mat with a thickness of 10 cm and a pore size of 15 cm is laid on top of the basalt gravel layer.

[0048] like Figure 2 As shown, recessed areas 37 are spaced apart on the surface of the sediment collection platform 32. The recessed areas 37 are shallow saucer-shaped, with a depth of 0-10 cm, a diameter of 20-30 cm, and a spacing of 50-80 cm.

[0049] like Figure 1 As shown, biomimetic grass 44 is laid on the surface of the back-sea slope 4.

[0050] In one specific embodiment, the biomimetic grass 44 is made of high-strength, corrosion-resistant polyester fiber, with a grass height of 10-20cm, a plant spacing of 5-10cm, and a coverage rate of more than 80%. Through its flexible structure and high-density vegetation cover, it reduces wave energy and water flow speed.

[0051] like Figure 1 As shown, the core of the dike 2 also includes a set of bottom protection 22. The bottom protection 22 has a parallelogram cross-section and a thickness of 0.6 to 1.2 m. It is set on the dike foundation 1 on both sides of the core of the dike 2, and abuts against the outer edges of the seaward slope 3 and the back slope 4. Among them, the bottom protection 221 abutting against the seaward slope 3 is the seaside bottom protection 221, with a width of 6 to 10 m; the bottom protection 222 abutting against the back slope 4 is the shoreside bottom protection 222, with a width of 4 to 6 m.

[0052] like Figure 1 As shown, the core of the dike 2 also includes a set of prisms 23. Prisms 23 are prismatic structures with parallelogram cross-sections. Their long sides are parallel to the direction of the dike core and fixed to the upper surface of the bottom protection 22, abutting against the seaward slope 3 and the back slope 4. The top surface of prisms 23 has a width of 2-4m and a thickness of 2-4m.

[0053] In one specific embodiment, the bottom protection 22 is made of high-strength concrete and is firmly connected to the dike base 1, the seaward slope 3, and the back slope 4 by grouting. It has a compressive strength greater than or equal to C40, an average thickness of 1.0m, a sea-side bottom protection 221 width of 8m, and a shore-side bottom protection 221 width of 5m. The prism 23 is made of natural boulders with a maximum particle size of 2.8m, laid in layers and compacted. It has a parallelogram-shaped cross-section, a top surface width of 3m, and a thickness of 4m.

[0054] Example 1:

[0055] A device for protecting offshore wind turbine pile foundations from scour caused by reciprocating currents includes a dike base 1 and a core 2 set on the dike base 1. The core 2 has an isosceles trapezoidal cross-section, with a top width of 3m, a bottom width of 12m, and a height of 3m. The slope on the seaward side is 1:1.5, and the slope on the leeward side is 1:1.5.

[0056] Example 2:

[0057] A device for protecting offshore wind turbine pile foundations from scour caused by reciprocating flow under human-shaped submerged breakwaters includes:

[0058] Embankment 1.

[0059] Dike core 2 is set on dike foundation 1. Its cross-section is an isosceles trapezoid, with a top width of 3m, a bottom width of 12m, and a height of 3m. The slope on the seaward side is 1:1.5, and the slope on the leeward side is 1:1.5.

[0060] The sea-facing slope 3 is laid on the side of the seawall 2 closest to the ocean, with a slope of 1:1.5 and a thickness of 1.2m.

[0061] The seaward slope 4 is laid on the side of the dike core 2 away from the sea, with a slope of 1:1.5 and a thickness of 1.0m.

[0062] The top of the dike 5 is located at the top of the core of the dike 2. It has a triangular cross-section and its width gradually increases from the top down. The slope on the side facing the sea 3 is 1:1.5, and the slope on the side facing away from the sea 4 is 1:3. Its bottom abuts against the top of the slope facing the sea 3, the top of the core of the dike 2, and the top of the slope facing away from the sea 4, respectively.

[0063] Example 3:

[0064] A device for protecting offshore wind turbine pile foundations from scour caused by reciprocating current under human-shaped submerged breakwaters, characterized in that it comprises:

[0065] Embankment 1.

[0066] Dike core 2 is set on dike foundation 1. Its cross-section is an isosceles trapezoid with a top width of 3m. The slope on the seaward side is 1:1.5 and the slope on the leeward side is 1:1.5.

[0067] The seaward slope 3, laid on the ocean-facing side of the breakwater core 2, comprises, from top to bottom, a sedimentation zone 31, a sediment collection platform 32, and an erosion protection zone 33. The sedimentation zone 31 is located at the top of the seaward slope 3, with a slope of 1:1.5 and a thickness of 1.2m. The erosion protection zone 33 is located at the bottom of the seaward slope 3, its bottom abutting against the breakwater foundation 1, with a slope of 1:1.5. The sediment collection platform 32, 2.0m wide horizontally, is located between the sedimentation zone 31 and the erosion protection zone 33, connecting the two zones.

[0068] The seaward slope 4 is laid on the side of the seawall 2 away from the ocean, with a slope of 1:1.5 and a thickness of 1.0m.

[0069] The top of the dike 5 is located at the top of the core 2. It has a triangular cross-section and its width gradually increases from the top down. The slope on the side facing the sea 3 is 1:1.5, and the slope on the side facing away from the sea 4 is 1:3. Its bottom is connected to the top of the sedimentation zone 31, the top of the core 2, and the top of the slope 4.

[0070] Example 4:

[0071] A device for protecting offshore wind turbine pile foundations from scour caused by reciprocating current under human-shaped submerged breakwaters, characterized in that it comprises:

[0072] Embankment 1.

[0073] Dike core 2 is set on dike foundation 1. Its cross-section is an isosceles trapezoid with a top width of 3m. The slope on the seaward side is 1:1.5 and the slope on the leeward side is 1:1.5.

[0074] The seaward slope 3, laid on the ocean-facing side of the breakwater core 2, comprises, from top to bottom, a sedimentation zone 31, a sediment collection platform 32, and an erosion protection zone 33. The sedimentation zone 31 is located at the top of the seaward slope 3, with a slope of 1:1.5 and a thickness of 1.2m. The erosion protection zone 33 is located at the bottom of the seaward slope 3, its bottom abutting against the breakwater foundation 1, with a slope of 1:1.5. The sediment collection platform 32, 6.0m wide horizontally, is located between the sedimentation zone 31 and the erosion protection zone 33, connecting the two zones.

[0075] The seaward slope 4 is laid on the side of the seawall 2 away from the ocean, with a slope of 1:1.5 and a thickness of 1.0m.

[0076] The top of the dike 5 is located at the top of the core 2. It has a triangular cross-section and its width gradually increases from the top down. The slope on the side facing the sea 3 is 1:1.5, and the slope on the side facing away from the sea 4 is 1:3. Its bottom is connected to the top of the sedimentation zone 31, the top of the core 2, and the top of the slope 4.

[0077] Example 5:

[0078] A device for protecting offshore wind turbine pile foundations from scour caused by reciprocating current under human-shaped submerged breakwaters, characterized in that it comprises:

[0079] Embankment 1.

[0080] Dike core 2 is set on dike foundation 1. Its cross-section is an isosceles trapezoid with a top width of 3m. The slope on the seaward side is 1:1.5 and the slope on the leeward side is 1:1.5.

[0081] The seaward slope 3, laid on the ocean-facing side of the breakwater core 2, comprises, from top to bottom, a sedimentation zone 31, a sediment collection platform 32, and an erosion protection zone 33. The sedimentation zone 31 is located at the top of the seaward slope 3, with a slope of 1:1.5 and a thickness of 1.2m. The erosion protection zone 33 is located at the bottom of the seaward slope 3, its bottom abutting against the breakwater foundation 1, with a slope of 1:1.5. The sediment collection platform 32, 10.0m wide horizontally, is located between the sedimentation zone 31 and the erosion protection zone 33, connecting the two zones.

[0082] The seaward slope 4 is laid on the side of the seawall 2 away from the ocean, with a slope of 1:1.5 and a thickness of 1.0m.

[0083] The top of the dike 5 is located at the top of the core 2. It has a triangular cross-section and its width gradually increases from the top down. The slope on the side facing the sea 3 is 1:1.5, and the slope on the side facing away from the sea 4 is 1:3. Its bottom is connected to the top of the sedimentation zone 31, the top of the core 2, and the top of the slope 4.

[0084] Example 6:

[0085] A device for protecting offshore wind turbine pile foundations from scour caused by reciprocating current under human-shaped submerged breakwaters, characterized in that it comprises:

[0086] Embankment 1.

[0087] Dike core 2 is set on dike foundation 1. Its cross-section is an isosceles trapezoid with a top width of 3m. The slope on the seaward side is 1:1.5 and the slope on the leeward side is 1:1.5.

[0088] The seaward slope 3, laid on the ocean-facing side of the breakwater core 2, comprises, from top to bottom, a sedimentation zone 31, a sediment collection platform 32, and an erosion protection zone 33. The sedimentation zone 31 is located at the top of the seaward slope 3, with a slope of 1:1.5 and a thickness of 1.2m. The erosion protection zone 33 is located at the bottom of the seaward slope 3, its bottom abutting against the breakwater foundation 1, with a slope of 1:1.5. The sediment collection platform 32, 6.0m wide horizontally, is located between the sedimentation zone 31 and the erosion protection zone 33, connecting the two zones.

[0089] The seaward slope 4 is laid on the side of the seawall 2 away from the ocean, with a slope of 1:1.5 and a thickness of 1.0m.

[0090] The top of the dike 5 is located at the top of the core 2. It has a triangular cross-section and its width gradually increases from the top down. The slope on the side facing the sea 3 is 1:1.5, and the slope on the side facing away from the sea 4 is 1:3. Its bottom is connected to the top of the sedimentation zone 31, the top of the core 2, and the top of the slope 4.

[0091] Diversion channels 34 are spaced apart on the surface of the sedimentation zone 31. Each diversion channel 34 is spaced apart along the slope of the sedimentation zone 31, including a main channel 341 and branch channels 342 extending from the center of the main channel 341 to both sides.

[0092] Example 7:

[0093] A device for protecting offshore wind turbine pile foundations from scour caused by reciprocating current under human-shaped submerged breakwaters, characterized in that it comprises:

[0094] Embankment 1.

[0095] Dike core 2 is set on dike foundation 1. Its cross-section is an isosceles trapezoid with a top width of 3m. The slope on the seaward side is 1:1.5 and the slope on the leeward side is 1:1.5.

[0096] The seaward slope 3, laid on the ocean-facing side of the breakwater core 2, comprises, from top to bottom, a sedimentation zone 31, a sediment collection platform 32, and an erosion protection zone 33. The sedimentation zone 31 is located at the top of the seaward slope 3, with a slope of 1:1.5 and a thickness of 1.2m. The erosion protection zone 33 is located at the bottom of the seaward slope 3, its bottom abutting against the breakwater foundation 1, with a slope of 1:1.5. The sediment collection platform 32, 6.0m wide horizontally, is located between the sedimentation zone 31 and the erosion protection zone 33, connecting the two zones.

[0097] The seaward slope 4 is laid on the side of the seawall 2 away from the ocean, with a slope of 1:1.5 and a thickness of 1.0m.

[0098] The top of the dike 5 is located at the top of the core 2. It has a triangular cross-section and its width gradually increases from the top down. The slope on the side facing the sea 3 is 1:1.5, and the slope on the side facing away from the sea 4 is 1:3. Its bottom is connected to the top of the sedimentation zone 31, the top of the core 2, and the top of the slope 4.

[0099] Diversion channels 34 are spaced apart on the surface of the sedimentation zone 31. Each diversion channel 34 is spaced apart along the slope of the sedimentation zone 31, including a main channel 341 and branch channels 342 extending from the center of the main channel 341 to both sides.

[0100] A grid guide plate 35 is installed at the connection between the sedimentation zone 31 and the sediment collection platform 32. The grid guide plate 35 is made of intersecting corrosion-resistant steel plates, and the strip structure forms a grid with a pore size of 30 cm.

[0101] Example 8:

[0102] A device for protecting offshore wind turbine pile foundations from scour caused by reciprocating current under human-shaped submerged breakwaters, characterized in that it comprises:

[0103] Embankment 1.

[0104] Dike core 2 is set on dike foundation 1. Its cross-section is an isosceles trapezoid with a top width of 3m. The slope on the seaward side is 1:1.5 and the slope on the leeward side is 1:1.5.

[0105] The seaward slope 3, laid on the ocean-facing side of the breakwater core 2, comprises, from top to bottom, a sedimentation zone 31, a sediment collection platform 32, and an erosion protection zone 33. The sedimentation zone 31 is located at the top of the seaward slope 3, with a slope of 1:1.5 and a thickness of 1.2m. The erosion protection zone 33 is located at the bottom of the seaward slope 3, its bottom abutting against the breakwater foundation 1, with a slope of 1:1.5. The sediment collection platform 32, 6.0m wide horizontally, is located between the sedimentation zone 31 and the erosion protection zone 33, connecting the two zones.

[0106] The seaward slope 4 is laid on the side of the seawall 2 away from the ocean, with a slope of 1:1.5 and a thickness of 1.0m.

[0107] The top of the dike 5 is located at the top of the core 2. It has a triangular cross-section and its width gradually increases from the top down. The slope on the side facing the sea 3 is 1:1.5, and the slope on the side facing away from the sea 4 is 1:3. Its bottom is connected to the top of the sedimentation zone 31, the top of the core 2, and the top of the slope 4.

[0108] Diversion channels 34 are spaced apart on the surface of the sedimentation zone 31. Each diversion channel 34 is spaced apart along the slope of the sedimentation zone 31, including a main channel 341 and branch channels 342 extending from the center of the main channel 341 to both sides.

[0109] A grid guide plate 35 is installed at the connection between the sedimentation zone 31 and the sediment collection platform 32. The grid guide plate 35 is made of intersecting corrosion-resistant steel plates, and the strip structure forms a grid with a pore size of 30 cm.

[0110] The sediment collection platform 32 is covered with a retention layer 36. The retention layer 36 includes a 20cm thick basalt gravel layer on the surface of the sediment collection platform 32 and a 10cm thick high-density polyethylene mesh mat with a 15cm pore size laid on top of the basalt gravel layer.

[0111] Recessed areas 37 are spaced apart on the surface of the sediment collection platform 32. The recessed areas 37 are shallow saucer-shaped, with a maximum depth of 10 cm, a radius of 25 cm, and a spacing of 80 cm.

[0112] The surface of the back-sea slope 4 is covered with biomimetic grass 44, which is made of high-strength, corrosion-resistant polyester fiber. The grass is 15cm high, the plant spacing is 20cm, and the coverage rate is 85%.

[0113] Example 9:

[0114] A device for protecting offshore wind turbine pile foundations from scour caused by reciprocating current under human-shaped submerged breakwaters, characterized in that it comprises:

[0115] Embankment 1.

[0116] Dike core 2 is set on dike foundation 1. Its cross-section is an isosceles trapezoid with a top width of 3m. The slope on the seaward side is 1:1.5 and the slope on the leeward side is 1:1.5.

[0117] The seaward slope 3, laid on the ocean-facing side of the breakwater core 2, comprises, from top to bottom, a sedimentation zone 31, a sediment collection platform 32, and an erosion protection zone 33. The sedimentation zone 31 is located at the top of the seaward slope 3, with a slope of 1:1.5 and a thickness of 1.2m. The erosion protection zone 33 is located at the bottom of the seaward slope 3, its bottom abutting against the breakwater foundation 1, with a slope of 1:1.5. The sediment collection platform 32, 6.0m wide horizontally, is located between the sedimentation zone 31 and the erosion protection zone 33, connecting the two zones.

[0118] The seaward slope 4 is laid on the side of the seawall 2 away from the ocean, with a slope of 1:1.5 and a thickness of 1.0m.

[0119] The top of the dike 5 is located at the top of the core 2. It has a triangular cross-section and its width gradually increases from the top down. The slope on the side facing the sea 3 is 1:1.5, and the slope on the side facing away from the sea 4 is 1:3. Its bottom is connected to the top of the sedimentation zone 31, the top of the core 2, and the top of the slope 4.

[0120] A riprap cushion layer 21 is provided between the core of the dike 2 and the seaward slope 3, and between the core of the dike 2 and the back slope 4. The riprap cushion layer 21 is made of natural riprap with a maximum particle size of 0.6m, laid in layers, compacted, and grouted with cement mortar, with an average thickness of 0.6m.

[0121] A set of bottom protection 22 is installed on both sides of the core 2. The bottom protection 22 has a parallelogram cross-section and an average thickness of 0.6m. It is installed on the foundation 1 on both sides of the core 2, and abuts against the outer edge of the erosion protection zone 33 and the back slope 4. The bottom protection abutting against the erosion protection zone 33 is the seaside bottom protection, with a width of 6m. The bottom protection abutting against the back slope 4 is the shoreside bottom protection, with a width of 4m.

[0122] A set of prisms 23 are also set on both sides of the core 2. The prisms 23 are prismatic structures with parallelogram cross-sections. They are fixed to the upper surface of the bottom protection 22 parallel to the direction of the core 2 and abut against the erosion protection zone 33 and the back slope 4. The top surface is 0.6m wide and 0.8m high.

[0123] Diversion channels 34 are spaced apart on the surface of the sedimentation zone 31. Each diversion channel 34 is spaced apart along the slope of the sedimentation zone 31, including a main channel 341 and branch channels 342 extending from the center of the main channel 341 to both sides. The cross-sections of the main channel 341 and the branch channels 342 are both semi-circular.

[0124] A grid guide plate 35 is installed at the connection between the sedimentation zone 31 and the sediment collection platform 32. The grid guide plate 35 is made of intersecting corrosion-resistant steel plates, and the strip structure forms a grid with a pore size of 30 cm.

[0125] The sediment collection platform 32 is covered with a retention layer 36. The retention layer 36 includes a 20cm thick basalt gravel layer on the surface of the sediment collection platform 32 and a 10cm thick high-density polyethylene mesh mat with a 15cm pore size laid on top of the basalt gravel layer.

[0126] Recessed areas 37 are spaced apart on the surface of the sediment collection platform 32. The recessed areas 37 are shallow saucer-shaped, with a maximum depth of 10 cm, a radius of 25 cm, and a spacing of 80 cm.

[0127] The surface of the back-sea slope 4 is covered with biomimetic grass 44, which is made of high-strength, corrosion-resistant polyester fiber. The grass is 15cm high, the plant spacing is 20cm, and the coverage rate is 85%.

[0128] Water tank experiment:

[0129] The experiment was conducted in a wave flume in accordance with JTJ / T234—2001 "Wave Model Test Procedure" and JTS154—2018 "Design Code for Breakwaters and Revetments". A submerged breakwater and pile foundation model were set up with a geometric scale of 1:25 to simulate a reciprocating flow period of 2.0s and a wave height of 0.08m.

[0130] The wave flume used in this experiment was 40m long, 0.8m wide, and 1.0m high. A 0.2m thick layer of bottom mud was laid at the bottom of the flume and leveled, then filled with water at an elevation of 0.4m. A wave generator was installed at one end of the flume to simulate reciprocating flow. A circular steel column with a diameter of 0.6m was installed at the other end of the flume to simulate offshore wind turbine piles. A scaled-down submerged breakwater model was placed at the center of the flume, with a 5m distance between the breakwater model and the circular steel column. In addition, a digital elevation model (DEM) device was installed inside the wave flume to obtain three-dimensional sedimentary geomorphological features and cross-sectional sedimentary variation characteristics.

[0131] This experiment consisted of nine experimental groups, corresponding to the devices in Examples 1 to 9, to detect the sediment retention rate, scour pit range, and maximum scour depth of each experimental group under the same wave conditions. Each element was repeated three times in the experiment, and the final calculation results were averaged. The experimental results are shown in the table below:

[0132] Table 1. Results of the water tank experiment

[0133]

[0134] Sediment retention rate refers to the percentage of sediment intercepted by a submerged breakwater relative to the total amount of sediment entering the breakwater. It is calculated using the formula: Sediment retention rate = [(Sediment entering the breakwater) - (Sediment leaving the breakwater)] / (Sediment entering the breakwater) × 100%. Specifically, before the experiment, the volume of bottom sediment on the sea side and pile side of the breakwater was measured and recorded as V1 and V2, respectively. After the experiment, the volume of bottom sediment on the sea side and pile side of the breakwater was measured and recorded as V3 and V4, respectively. The amount of sediment entering the breakwater is V1-V3, and the amount of sediment leaving the breakwater is V2-V4.

[0135] The scour pit area refers to the horizontal projected area of ​​the region where the bottom of the water tank is below the reference surface depth threshold after the experiment. The initial horizontal surface of the bottom mud of the water tank before the experiment is used as the reference surface. In this experiment, the depth threshold is specified as 1 mm, meaning that the area where the pile side is 1 mm below the reference surface after the test is considered the scoured area.

[0136] The maximum scouring depth refers to the vertical distance from the deepest point of the scouring area at the bottom of the tank to the reference surface after the experiment.

[0137] In Experiment 1 and Experiment 2, the sediment retention rate increased slightly, while the area of ​​the scour pit and the maximum scour depth both decreased. Example 2 added a seaward slope, a leeward slope, and a triangular breakwater crest to Example 1. The slope structures of the seaward and leeward slopes, along with the triangular breakwater crest, dispersed the energy of the water flow as it approached the submerged breakwater, mitigating scour. However, this effect was limited, mainly due to the lack of an effective mechanism for intercepting and guiding sediment.

[0138] In Experiments 2 and 3, the sediment retention rate was significantly improved, while the area of ​​the scour pit and the maximum scour depth decreased substantially. Example 3, based on Example 2, added a sedimentation zone, a sediment collection platform (2.0m wide), and an erosion protection zone to the seaward slope. The newly added sedimentation zone, sediment collection platform, and erosion protection zone in Example 3 constitute an active system for intercepting and retaining sediment. The sedimentation zone slows the water flow velocity and promotes sediment settling; the collection platform provides space for sediment accumulation; and the erosion protection zone protects the bottom of the submerged breakwater from direct scouring.

[0139] In experimental groups three, four, and five, as the width of the sediment collection platform increased, the sediment retention rate continuously improved, while the area of ​​the scour pit and the maximum scour depth continuously decreased. The main effect of increasing the width of the sediment collection platform is to increase the sediment retention area. A larger area allows more sediment to be intercepted and retained, thereby reducing the amount of sediment reaching the wind turbine foundation and thus reducing the depth and extent of scour.

[0140] In experimental groups four and six, the sediment retention rate increased slightly, while the area of ​​the scour pit and the maximum scour depth decreased slightly. Diversion channels can effectively guide water flow, altering its path and velocity. By setting up diversion channels in the sedimentation zone, some water flow can be guided around the sediment, reducing the flow velocity and the scouring force on the sediment, thereby increasing the sediment retention rate. However, the effect is not as significant as expanding the sediment collection platform.

[0141] In experimental groups six and seven, the sediment retention rate increased slightly, while the area of ​​the scour pit and the maximum scour depth decreased slightly. The grid deflector intercepted some of the larger sediment particles, which accumulated on the grid, thereby reducing the amount of sediment reaching downstream and protecting the erosion-resistant zone from scouring.

[0142] In experimental groups seven and eight, the sediment retention rate was significantly increased, while the area of ​​the scour pit and the maximum scour depth decreased substantially. The retention layer increased the friction of the sediment by increasing surface roughness and porosity; the depression area created additional sediment accumulation areas; and the biomimetic grass increased the surface roughness of the leeward slope and reduced the flow velocity on the leeward slope, all of which together significantly improved the scour prevention effect.

[0143] In experimental groups eight and nine, the sediment retention rate was further improved, while the area of ​​the scour pit and the maximum scour depth were further reduced. The riprap cushion layer enhanced the connection strength between the dike core and the seaward / backward slope, preventing slippage or displacement between the dike core and the slope; the bottom protection significantly increased the protection of the bottom of the seaward slope, preventing scour from the bottom of the seaward slope; the prismatic structure increased the scour resistance of the dike core, effectively dispersed the energy of the water flow, reduced the scour effect of the water flow on the dike core, and enhanced the structural stability, protected the bottom of the dike core, and dispersed the energy of the water flow, ultimately significantly improving the anti-scour performance of the device.

[0144] Based on the preferred embodiments of the present invention described above, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A device for protecting a wind turbine foundation from scouring by reciprocating flow under a human-shaped submerged dike, characterized in that, The application relates to a seawall structure, which comprises: a seawall base (1); a seawall core (2) arranged on the seawall base (1) and having a trapezoidal cross section; a seawall slope (3) arranged on the seawall core (2) close to the sea and comprising, from top to bottom, a deposition area (31), a sediment collection platform (32) and an erosion prevention area (33); the deposition area (31) is located at the top of the seawall slope (3) and has a slope of 1:1.5-1:3; the erosion prevention area (33) is located at the bottom of the seawall slope (3) and abuts against the seawall base (1); the sediment collection platform (32) is located between the deposition area (31) and the erosion prevention area (33) and connects the deposition area (31) and the erosion prevention area (33); a seawall slope (4) arranged on the seawall core (2) away from the sea and having a slope of 1:1.5-1:3; a seawall top (5) arranged on the top of the seawall core (2) and having a triangular cross section; the width of the seawall top (5) gradually increases from the top to the bottom, and the bottom of the seawall top (5) abuts against the top of the deposition area (31), the top of the seawall core (2) and the top of the seawall slope (4) respectively.

2. A device for protecting a pile foundation of a wind turbine from scour according to claim 1, characterized in that The width of the sediment collection platform (32) is 1.5-3 times the width of the seawall core (2).

3. A device for protecting a pile foundation of a wind turbine from scour according to claim 2, wherein, The deposition area (31) is provided with a plurality of shunt grooves (34) at intervals; each shunt groove (34) is arranged at intervals along the slope direction of the deposition area (31) and comprises a main groove (341) and branch grooves (342) extending from the center of the main groove (341) to both sides.

4. A device for protecting a pile foundation of a wind turbine from scour according to claim 3, wherein, A grid flow guide plate (35) is arranged at the joint of the deposition area (31) and the sediment collection platform (32); the grid flow guide plate (35) is composed of strip structures which cross each other and form grid cells with a pore size of 20-40 cm.

5. A device for protecting a pile foundation of a wind turbine from scour according to claim 4, wherein, The surface of the sediment collection platform (32) is paved with a retention layer (36); the retention layer (36) comprises one or more of a basalt gravel layer and a high-density polyethylene grid mat; the basalt gravel layer has a particle size of 5-20 cm and a thickness of 10-30 cm; the high-density polyethylene grid mat has a pore size of 10-20 cm and a thickness of 5-15 cm.

6. A device for protecting a pile foundation of a wind turbine from scour according to claim 5, wherein, The surface of the sediment collection platform (32) is provided with recessed areas (37) at intervals; the recessed areas (37) are shallow dishes with a depth of 0-10 cm, a diameter of 20-30 cm and an interval of 50-80 cm.

7. A device for protecting a pile foundation of a wind turbine from scour according to claim 6, wherein the device is configured to be arranged on the seabed in front of the pile foundation. Bionic grass (44) is paved on the surface of the seawall slope (4).

8. A device for protecting a pile foundation of a wind turbine from scour according to claim 2, wherein, A stone cushion layer (21) is arranged between the seawall core (2) and the seawall slope (3) and between the seawall core (2) and the seawall slope (4).

9. A device for protecting a pile foundation of a wind turbine from scour according to claim 8, wherein, The seawall core (2) further comprises a group of bottom protections (22); the bottom protections (22) have a parallelogram cross section and a thickness of 0.6-1.2 m; the bottom protections (22) are arranged on the seawall base (1) on both sides of the seawall core (2) and abut against the outer edges of the seawall slope (3) and the seawall slope (4); the bottom protection (22) which abuts against the seawall slope (3) is a seaward bottom protection and has a width of 6-10 m; the bottom protection (22) which abuts against the seawall slope (4) is a landward bottom protection and has a width of 4-6 m.

10. A device for protecting a pile foundation of a wind turbine from scour according to claim 9, wherein, The dike core (2) further comprises a set of prisms (23); the prism (23) is a prism structure with a parallelogram cross section, and the long side is fixed on the upper surface of the bottom protection (22) in parallel with the dike core direction and abuts against the seaward slope (3) and the landward slope (4) respectively; the top surface of the prism (23) is 2-4 m wide and 2-4 m thick.

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