An anti-scouring and vibration reduction device for offshore wind power monopile foundation

Abstract

A scour prevention and vibration reduction device for an offshore wind power monopile foundation comprises a flow barrier (1), an arc-shaped wing plate (2), an annular fixing member (3) and a vibration reduction device (4). The bottom of the flow barrier is rigidly connected to a structure below the soil surface (6), is evenly distributed on the fixing member connection component of the structure below, and is connected to the annular fixing member at the top; the surface of the arc-shaped wing plate is a smooth arc curve, and the overall structure is sleeved on the wind power monopile foundation (5), and is embedded with a vibration reduction device, six embedded vibration reduction devices, and are evenly distributed around the wind power monopile foundation; the vibration reduction device comprises pre-stressed springs on both sides and the bottom, and a mass block. The present invention adopts a three-ring pipe pile and top fixing member structure, and the fixing members at the top of the three-ring pipe pile are connected to form a whole by the top fixing member; it plays a good anti-scour role. The vibration reduction device generates resonance to reduce the vibration of the pile body. The present invention is suitable for scour prevention and vibration reduction of offshore wind power monopile foundations.

Description

Technical Field

[0001] The invention relates to an anti-scour and vibration reduction device for an offshore wind power monopile foundation, belonging to the technical field of offshore wind power vibration and anti-scour. Background Art

[0002] Offshore wind turbine monopile foundations typically consist of a steel pipe pile with a circular cross-section. The substructure is deeply embedded in the soil, providing load-bearing capacity together with the surrounding soil. The central foundation primarily withstands horizontal cyclic loads such as waves and tides. Monopile foundations are the primary foundation type for offshore wind power facilities in my country, offering a simple structure, good economic benefits, and excellent load-bearing capacity. With the increasing application and widespread adoption of offshore wind power technology, and improvements in domestic pile manufacturing and sinking capabilities, monopile foundations are poised for future application in offshore wind farm construction in my country.

[0003] Offshore wind turbine pile foundations are primarily subjected to forces from wind, waves, and the structure's own weight, primarily in the form of horizontal loads and vertical loads caused by its own weight. During design, as pile foundations are subject to long-term dynamic loads, the foundation's horizontal bearing capacity must be a key consideration. However, under long-term horizontal cyclic loads, the surrounding soil of a single pile foundation is affected by factors such as pile vibration and wave erosion, making it unable to provide sufficient side soil resistance. This severely weakens the pile foundation's horizontal bearing capacity and even threatens the safety of the wind turbine equipment. Summary of the Invention

[0004] The purpose of the present invention is to solve the problem of reduced bearing capacity of offshore wind turbine monopile foundations caused by vibrations transmitted from the superstructure and local scouring of the seabed, and to propose an anti-scouring and vibration reduction device for offshore wind turbine monopile foundations.

[0005] The technical solution implemented by the present invention is as follows: an anti-scour and vibration reduction device for an offshore wind turbine monopile foundation, comprising a flow cutoff plate, a curved wing plate, an annular fixing member, and a vibration reduction device; the bottom of the flow cutoff plate is rigidly connected to the structure below the soil, and is evenly distributed on the fixing connecting components of the structure below, and the top is connected to the annular fixing member; the surface of the curved wing plate is a smooth arc curve, and the entire structure is mounted on the wind turbine monopile foundation, and has an embedded vibration reduction device. Six embedded vibration damping devices are evenly distributed around the wind turbine single pile foundation; the vibration damping device includes pre-stressed springs on both sides and the bottom, and a mass block, one end of the pre-stressed spring at the bottom is connected to the mass block, and the other end is connected to the outer wall of the arc-shaped wing plate, one end of the pre-stressed spring on both sides is connected to the inner wall of the arc-shaped wing plate or the wind turbine single pile foundation, and one end is connected to the mass block; the structure below the soil includes a number of hollow pipe piles, a number of ring pipe pile top fixings, and a number of fixing connection components; the hollow pipe piles are three-layered, the top fixings of the first ring pipe piles are rigidly connected to the arc-shaped wing plate of the upper structure, the pipe pile body is driven into the soil layer, and the innermost layer of pipe piles are connected as a whole by the arc-shaped wing plate; the top fixings of the second ring pipe piles are connected as a whole by the top fixings, and the fixings are connected to the arc-shaped wing plate of the upper structure; the top fixings of the third ring pipe piles are connected as a whole by the top fixings; the inner and outer rings are connected by fixing connection components; the middle area between the inner and outer rings is soil.

[0006] The hollow pipe pile is driven into the soil layer before the wind power monopile structure is sunk. The structural material below the soil is reinforced concrete, and the connections between the components are rigid connections.

[0007] The flow cutoff is made of reinforced concrete and is rigidly connected to the fixing member connecting component to form a whole. The upper portion of the flow cutoff is also rigidly connected to the annular fixing member.

[0008] The annular fixing member is flexibly connected to the wind power pile foundation, and there is a circle of rubber gasket on the contact surface to prevent the anti-scouring and vibration reduction device from shearing the single pile foundation during use.

[0009] The bottom of the curved wing panels directly contacts the soil and is rigidly connected to the pile. In addition to the vibration damping device, a rubber gasket is placed on each side of the wing panels to prevent uneven settlement from causing the device to shear against the pile. Gaps exist between the curved wing panels. These gaps can be filled with reinforced concrete before construction. Alternatively, considering the complex working conditions, the gaps can be filled with underwater concrete after the device has been lowered and stabilized.

[0010] The lengths of the hollow pipe piles in each ring in the structure below the soil are different. The outer ring pipe piles are longer than the inner ring. The outer ring is longer and the inner ring is shorter. This is because the top of the inner ring is a closed structure and the top of the outer ring is an open structure. The soil is completely exposed, and the diversion direction of the overall structure of the device is from the inner ring to the outer ring. This places higher requirements on the soil stabilization function of the outer ring device.

[0011] The beneficial effects of the present invention are as follows: the present invention adopts a three-ring pipe pile and top fixing structure, the fixings at the top of the three-ring pipe pile are connected as a whole by the top fixing; the inner and outer rings are connected by fixing connecting parts; the middle area of ​​the inner and outer rings is soil, and the flow barrier and the arc-shaped wing plate play a good anti-scouring role, greatly improving the bearing capacity of the wind power single pile foundation; the vibration reduction device designed in the arc-shaped wing plate, because the pre-stressed spring of the vibration reduction device is connected to the pile body at one end and to the arc-shaped wing plate at the other end, when the pile body generates vibrations due to wind and wave loads and during operation and is transmitted to the vibration reduction device, the vibration reduction device will resonate and reduce the vibration of the pile body. The present invention is suitable for anti-scouring and vibration reduction of offshore wind power single pile foundations. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a structural schematic diagram of the anti-scour and vibration reduction device of the present invention;

[0013] Figure 2 for Figure 1 AA view, a schematic diagram of the structure below the soil body of the present invention;

[0014] Figure 3 for Figure 1 BB view, a schematic diagram of the upper structure of the present invention;

[0015] Figure 4 It is a partial enlarged view of the inner ring of the present invention;

[0016] In the figure, 1 is a flow separator; 2 is an arc-shaped wing plate; 3 is an annular fixing member; 4 is a vibration reduction device; 5 is a wind turbine single pile foundation; 6 is the soil surface; 7 is a fixing member at the top of a single-ring pipe pile; 8 is a fixing member at the top of a second-ring pipe pile; 9 is a fixing member at the top of a third-ring pipe pile; 10 is a fixing member connecting member; 11 is a hollow pipe pile; 12 is a connecting member connecting the annular fixing member and the top of the arc-shaped wing plate; 13 is a gap between the arc-shaped wing plates; 14 is a preload spring; and 15 is a mass block. DETAILED DESCRIPTION

[0017] The present invention will be further described in detail through embodiments with reference to the accompanying drawings.

[0018] The target wind turbine monopile foundation in this embodiment has a radius of R = 3.0 m and a burial depth of l = 40.0 m. The soil surrounding the monopile is overlain by a soft clay layer and a sandy soil layer. The monopile foundation is located near the sea, with a predicted scour pit angle of 30°, a radius of 3R-4R, and a depth of 2R-2.6R. To protect the core soil around the pile, the first ring is located 3 m from the monopile, approximately one-third of the scour pit radius, and the pile height is the corresponding height L = 1.5R. The third ring is located 9 m from the monopile, with a pile height of 0.5R. The second ring takes a midpoint between the height and distance.

[0019] like Figure 1 As shown, this embodiment provides an anti-scouring and vibration reduction device for an offshore wind power monopile foundation, including an anti-scouring device and a vibration reduction device.

[0020] The anti-scour device of the wind turbine monopile foundation in this embodiment includes a flow cutoff plate 1, an arc-shaped wing plate 2, and an annular fixing member 3. The bottom of the flow cutoff plate 2 is rigidly connected to the structure below the soil of the wind turbine monopile foundation 5, and the flow cutoff plate 2 is evenly distributed on the fixing connecting components of the structure below the soil of the wind turbine monopile foundation 5. The top of the flow cutoff plate 2 is connected to the annular fixing member 3. The vibration reduction device 4 is installed between the pile body and the arc-shaped wing plate 2.

[0021] The structure below the soil of the wind turbine monopile foundation includes a number of hollow pipe piles 11, top fixings of inner ring pipe piles, top fixings of outer ring pipe piles, and a number of fixing connection parts.

[0022] Combine Figure 2 and Figure 3 As shown, the vibration reduction device 4 of this embodiment is a structure buried in the arc-shaped wing plate 2, which includes three pre-stressed springs 14 and a mass block 15. One end of the pre-stressed spring 14 at the bottom is connected to the mass block 15, and the other end is connected to the outer wall of the arc-shaped wing plate 2; one end of the pre-stressed spring 14 on both sides is connected to the inner wall of the arc-shaped wing plate 2 or the wind turbine single pile foundation 5, and the other end is connected to the mass block 15; when the pile body vibrates due to wind and wave loads and during operation and is transmitted to the vibration reduction device 4, the vibration reduction device 4 will resonate to reduce the vibration of the pile body.

[0023] It should be noted that, since one end of the pre-stressed spring 14 of the vibration damping device 4 is connected to the pile body and the other end is connected to the arc-shaped wing plate 2, in order to prevent the vibration damping device 4 from entering water underwater during construction, it is necessary to reserve a construction hole for the vibration damping device 4 first, and then use underwater concrete to seal it after the vibration damping device 4 is assembled.

[0024] In order to ensure that there is uneven force between the wind turbine single pile foundation 5 and the anti-scour and vibration reduction device, a certain gap is left between the anti-scour and vibration reduction device and the wind turbine single pile foundation 5, which is filled with a flexible rubber gasket to prevent the device from shearing the pile body after uneven settlement.

[0025] The outer side of the vibration reduction device 4 of this embodiment is an arc-shaped wing plate 2, with a total of six pieces, evenly distributed around the pile body; there are gaps between adjacent arc-shaped wings 2. In actual engineering, if the soil surface is relatively smooth, the soil density is relatively uniform, and there is no problem of uneven settlement, etc., the individual wing plates can be assembled in the factory, the gaps can be filled with concrete, and then lowered uniformly; if the soil surface is uneven and uneven, the individual arc-shaped wing plates can be installed separately and then filled with underwater concrete to connect them.

[0026] The top of the arc-shaped wing plate 2 of this embodiment is a circle of annular fixing members 3 , and each of the annular fixing members has a connecting member 12 on the left and right sides rigidly connected to the top of the arc-shaped wing plate 2 .

[0027] The outer side of the vibration reduction device 4 of this embodiment is an arc-shaped wing plate 2. There are 6 arc-shaped wing plates 2 in total, which are evenly distributed around the pile body. There are gaps between adjacent arc-shaped wing plates 2. In actual engineering, if the soil surface is relatively smooth, the soil density is relatively uniform, and there is no problem of uneven settlement, the various arc-shaped wing plates can be assembled in the factory, the gaps can be filled with concrete, and then lowered uniformly; if the soil surface is uneven and uneven, the various arc-shaped wing plates can be installed separately and then filled with underwater concrete for connection.

[0028] The top of the arc-shaped wing plate 2 of this embodiment is a circle of annular fixing members 3 , and each of the left and right fixing members has a connecting member 12 rigidly connected to the top of the arc-shaped wing plate 2 .

[0029] In this embodiment, there are six flow dividers 1 evenly distributed on the outside of the structure above the soil. Their height is flush with the tops of the curved wing plates 2. The spaces between the wing plates are hollow, facilitating the passage of water transmitted by the inner curved wing plates 2. They can also isolate eddies generated around the single pile foundation, separating irregular water flows along the pile body and preventing large water flows from circling the pile body and impacting the soil below. The bottoms of the curved wing plates 2 are connected to the structure below the soil, and the tops of the curved wing plates 2, near the pile foundation, are connected to the annular fixing members 3, forming a unified structure above the soil to jointly bear the load.

[0030] like Figure 1 and Figure 2 As shown, the structure below the soil is divided into three layers from the inside to the outside, namely, a first ring of pipe piles and top fixings, a second ring of pipe piles and top fixings, and a third ring of pipe piles and top fixings; the second ring of fixings and the third ring of fixings are connected by fixing connecting parts, and the top of the pipe piles are the top fixings of each ring.

[0031] During construction, the pipe piles of each ring are first driven into the soil layer, and then the tops of the pipe piles of each ring are fixed and connected together by the fixing parts on the top of the pipe piles to form a whole.

[0032] In this embodiment, the diameter of the top fixing piece of the first ring pipe pile is 12m, and the diameter of the pipe pile is 0.5m; the diameter of the top fixing piece of the second ring pipe pile is 18m, and the diameter of the pipe pile is 0.5m; the diameter of the top fixing piece of the third ring pipe pile is 24m, and the diameter of the pipe pile is 0.5m;

[0033] It is worth noting that the fixing member connection component 10 is connected to the flow cutoff plate 1 in the structure above the soil.

[0034] Between the top fixings of the second-ring pipe pile and the top fixings of the third-ring pipe pile, except for the fixing connecting parts 10, the rest of the position is soil; and between the top fixings of the first-ring pipe pile and the top fixings of the second-ring pipe pile, the bottom of the curved wing plate in the structure above the soil is rigidly connected to the structure below the soil; the anti-scour device is thus connected as a whole, jointly bearing the effects of scour and load.

[0035] In this embodiment, the lengths of the hollow pipe piles 11 in each ring are different, with the outer ring being longer and the inner ring being shorter. This is because the top of the inner ring is a closed structure, while the top of the outer ring is an open structure, with the soil completely exposed. In addition, the diversion direction of the overall structure of the device is from the inner ring to the outer ring, which places higher requirements on the soil stabilizing function of the outer ring device. Therefore, the length of the outer ring pipe piles is greater than that of the inner ring.

[0036] Considering that the anti-scour device usually needs to cover 3-5 times the pile diameter, the overall structure cannot be too heavy, otherwise it will cause excessive settlement of the soil around the pile, which is not conducive to the load-bearing of the pile and construction, and has poor economic benefits. After comprehensive consideration, a structure with a hollow outside and a semi-solid inside was selected. While saving materials and ensuring convenient construction, it also takes into account the integrity of the device, anti-scour and vibration reduction performance.

Claims

1. An anti-scour and vibration reduction device for offshore wind power monopile foundation, characterized in that: The device includes a flow barrier, an arc-shaped wing plate, an annular fixing part and a vibration reduction device; the bottom of the flow barrier is rigidly connected to the structure below the soil, evenly distributed on the fixing connecting parts of the structure below the soil, and the top is connected to the annular fixing part; the surface of the arc-shaped wing plate is a smooth arc curve, and the overall structure is mounted on the wind turbine single pile foundation, with a vibration reduction device embedded therein, and six embedded vibration reduction devices are evenly distributed around the wind turbine single pile foundation; the vibration reduction device includes pre-stressed springs on both sides and the bottom, and a mass block, one end of the pre-stressed spring at the bottom is connected to the mass block, and the other end is connected to the outer wall of the arc-shaped wing plate, and one end of the pre-stressed springs on both sides is connected to the inner wall of the arc-shaped wing plate or the wind turbine single pile foundation, and one end is connected to the mass block; the structure below the soil includes a number of hollow pipe piles, a top fixing part of the inner ring pipe pile, a top fixing part of the outer ring pipe pile, and a number of fixing connecting parts; the structure below the soil is divided into three layers from the inside to the outside, namely, a ring pipe pile and a top fixing part, a second ring pipe pile and a second ring pipe pile. Piles and top fixings and three-ring pipe piles and top fixings; the second-ring fixings and the third-ring fixings are connected by fixing connection parts, and the top of the pipe piles are the top fixings of each ring; during construction, each ring of pipe piles is first driven into the soil layer, and then the tops of the pipe piles are fixed and connected together by the top fixings of each ring to form a whole; between the top fixings of the second-ring pipe piles and the top fixings of the three-ring pipe piles, except for the fixing connection parts, the rest of the position is soil; and between the top fixings of the first-ring pipe piles and the second-ring pipe piles, the bottom of the arc-shaped wing plate in the structure above the soil is rigidly connected to the structure below the soil.

2. The anti-scour and vibration reduction device for offshore wind power monopile foundation according to claim 1, characterized in that: The hollow pipe pile is driven into the soil layer before the wind power monopile structure is sunk. The structural material below the soil is reinforced concrete, and the connections between the components are rigid connections.

3. The anti-scour and vibration reduction device for offshore wind power monopile foundation according to claim 1, characterized in that: The flow cutoff is made of reinforced concrete and is rigidly connected to the fixing member connecting component to form a whole. The upper portion of the flow cutoff is also rigidly connected to the annular fixing member.

4. The anti-scour and vibration reduction device for offshore wind power monopile foundation according to claim 1, characterized in that: The annular fixing member is flexibly connected to the wind power pile foundation, and there is a circle of rubber gasket on the contact surface to prevent the anti-scouring and vibration reduction device from shearing the single pile foundation during use.

5. The anti-scour and vibration reduction device for offshore wind power monopile foundation according to claim 1, characterized in that: The bottom of the arc-shaped wing plate is in direct contact with the soil and is rigidly connected to the pipe pile. In addition to the vibration reduction device, there is a circle of rubber gasket on the side contact surface with the pile body to prevent uneven settlement from causing the device to shear the pile body.

6. The anti-scour and vibration reduction device for offshore wind power monopile foundation according to claim 1, characterized in that: The lengths of the hollow pipe piles in each ring in the structure below the soil are different. The outer ring pipe piles are longer than the inner ring. The outer ring is longer and the inner ring is shorter. This is because the top of the inner ring is a closed structure and the top of the outer ring is an open structure. The soil is completely exposed, and the diversion direction of the overall structure of the device is from the inner ring to the outer ring.

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