Anti-scouring and damping device for offshore wind power single pile foundation

Abstract

The invention relates to an anti-scouring and vibration damping device for an offshore wind power single pile foundation. The anti-scouring and vibration damping device comprises a flow isolating plate (1), an arc-shaped wing plate (2), an annular fixing piece (3) and a vibration damping device (4), the bottoms of the flow separation plates are rigidly connected with a structure below a soil body surface (6) and are uniformly distributed on fixing piece connecting parts of the structure below, and the tops of the flow separation plates are connected with the annular fixing pieces; the surface of the arc-shaped wing plate is a smooth arc-shaped curve, the whole structure is arranged on the wind power single pile foundation (5) in a sleeving mode, vibration reduction devices are embedded in the arc-shaped wing plate, and the six embedded vibration reduction devices are evenly distributed on the periphery of the wind power single pile foundation. The damping device comprises pre-pressing springs on the two sides and at the bottom and a mass block. The structure of the three-ring pipe pile and the top fixing part is adopted, and the fixing parts at the top of the three-ring pipe pile are connected into a whole through the top fixing part; and a good anti-scouring effect is achieved. And the damping device can generate resonance so as to reduce the vibration of the pile body. The method is suitable for scour prevention and vibration reduction of the offshore wind power single pile foundation.

Description

Technical Field

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

[0002] Offshore wind power monopile foundation is usually composed of a steel pipe pile with a circular cross section. The lower structure is deep into the soil and provides bearing capacity together with the soil around the pile. The middle foundation mainly bears horizontal cyclic loads such as waves and tides. The wind power monopile foundation has the characteristics of simple structure, good economic benefits, and excellent bearing capacity. It is the main foundation form of offshore wind power facilities in my country. With the application and popularization of offshore wind power generation technology, the improvement of domestic pile making technology and pile sinking capacity, the monopile foundation form will also have a good application prospect in the construction of offshore wind farms in my country in the future.

[0003] The offshore wind power pile foundation is mainly subjected to the forces of wind, waves and its own weight, mainly in the form of horizontal load and vertical load caused by its own weight. During the design, since the pile foundation is under the action of dynamic load for a long time, the horizontal bearing performance of the foundation must be considered. However, under the action of long-term horizontal cyclic load, the soil around the pile foundation is affected by factors such as pile vibration and wave scouring, and cannot provide sufficient pile side soil resistance, which seriously weakens the horizontal bearing capacity of the pile foundation and even threatens the safety of wind power 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 foundation caused by vibration transmitted by superstructure and local scouring of seabed, and to propose an anti-scouring and vibration reduction device for offshore wind turbine monopile foundation.

[0005] The technical solution implemented by the present invention is as follows: an anti-scour and vibration reduction device for an offshore wind power monopile foundation comprises a flow cutoff plate, an arc-shaped 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 body, evenly distributed on the fixing member connecting parts of the structure below, and the top is connected to the annular fixing member; the surface of the arc-shaped wing plate is a smooth arc curve, the overall structure is sleeved on the wind power monopile foundation, and a vibration reduction device is embedded in it, Six embedded vibration reduction devices are evenly distributed around the wind turbine monopile 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, 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 monopile foundation, and one end is connected to the mass block; the structure below the soil body includes a plurality of hollow pipe piles, a plurality of ring pipe pile top fixings, and a plurality of fixing connecting parts; 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 pile bodies of the pipe piles are 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 fixings at the top of the third ring pipe piles are connected as a whole by the top fixings; the inner and outer rings are connected by fixing connecting parts; 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 connection between the components is rigid connection.

[0007] The flow cutoff plate is made of reinforced concrete material and is rigidly connected to the fixing member connecting component to form a whole. The upper portion of the flow cutoff plate 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 arc-shaped wing plate is in direct contact with the soil, and the bottom is rigidly connected to the pipe pile; in addition to the vibration reduction device, there is a circle of rubber gaskets on the side and the contact surface of the pile body to prevent uneven settlement from causing the device to shear the pile body. There are gaps between the arc-shaped wing plates, and the gaps between the arc-shaped wing plates can be filled with reinforced concrete before construction. Considering the complex conditions of the actual working conditions, the gaps can also 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 stabilizing 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 a top fixing structure, the fixings on the top of the three-ring pipe pile are connected as a whole by the top fixings; 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 partition and the arc wing plate play a good anti-scouring role, greatly improving the bearing capacity of the wind power single pile foundation; the shock absorbing device designed in the arc wing plate, because the pre-stressed spring of the shock absorbing device is connected to the pile body at one end and connected to the arc wing plate at the other end, when the pile body is vibrated due to wind and wave loads and during operation and transmitted to the shock absorbing device, the vibration absorbing device will resonate to 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; Figure 2 for Figure 1 AA view, a schematic diagram of the structure below the soil body of the present invention; Figure 3 for Figure 1 BB view, a schematic diagram of the upper structure of the present invention; Figure 4 It is a partial enlarged view of the inner ring of the present invention; In the figure, 1 is a flow separator; 2 is an arc wing plate; 3 is an annular fixing part; 4 is a shock absorbing device; 5 is a wind turbine single pile foundation; 6 is a soil surface; 7 is a top fixing part of a first-ring pipe pile; 8 is a top fixing part of a second-ring pipe pile; 9 is a top fixing part of a third-ring pipe pile; 10 is a fixing connecting part; 11 is a hollow pipe pile; 12 is a connecting part connecting the annular fixing part and the top of the arc wing plate; 13 is a gap that appears when connecting each arc wing plate; 14 is a preload spring; and 15 is a mass block. DETAILED DESCRIPTION

[0013] The present invention will be further described in detail by way of embodiments in conjunction with the accompanying drawings.

[0014] The radius of the target wind power monopile foundation in this embodiment is R=3.0m, the burial depth is l=40.0m, the soil around the monopile is covered with a soft clay layer, and the underlying soil layer is a sand layer. The monopile foundation is located near the sea, and the predicted scour pit angle is 30º, the radius is 3R~4R, and the depth is 2R~2.6R; in order to protect the core soil around the pile, the first ring is located 3m away from the monopile, which is about one-third of the scour pit radius, and the pipe pile height is the corresponding height L=1.5R; the third ring is located 9m away from the monopile, and the pipe pile height is 0.5R; the second ring height and distance take the middle value.

[0015] like Figure 1As 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.

[0016] The anti-scouring 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 is evenly distributed on the fixing member connecting parts of the structure below the soil of the wind turbine monopile foundation 5, and 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.

[0017] The structure below the soil of the wind power monopile foundation includes a plurality of hollow pipe piles 11, top fixings of inner ring pipe piles, top fixings of outer ring pipe piles, and a plurality of fixing connection parts.

[0018] Combination 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, including 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 springs 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 is vibrated due to wind and wave loads and during operation and then transmitted to the vibration reduction device 4, the vibration reduction device 4 will produce resonance to reduce the vibration of the pile body.

[0019] 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.

[0020] In order to ensure that there is uneven force between the wind power single pile foundation 5 and the anti-scour and vibration reduction device, there is a certain gap between the anti-scour and vibration reduction device and the wind power single pile foundation 5, which is filled with a flexible rubber gasket to prevent the device from shearing the pile body after uneven settlement.

[0021] The outer side of the vibration reduction device 4 of this embodiment is an arc-shaped wing plate 2, which has a total of six pieces and is 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 consistent, and there is no problem of uneven settlement, then the 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, then the arc-shaped wing plates can be installed separately and then filled with underwater concrete for connection.

[0022] The top of the arc-shaped wing plate 2 of the present embodiment is a circle of annular fixing members 3 , and the annular fixing members have a connecting member 12 on each side rigidly connected to the top of the arc-shaped wing plate 2 .

[0023] 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, 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 consistent, and there is no problem of uneven settlement, then the 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, then the arc-shaped wing plates can be installed separately and then filled with underwater concrete for connection.

[0024] The top of the arc-shaped wing plate 2 of the present embodiment is a circle of annular fixing members 3 , and each of the 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 .

[0025] There are six flow dividers 1 in this embodiment, which are evenly distributed on the outside of the structure above the soil. The height is flush with the top of the arc-shaped wing plate 2. The space between the wing plates is hollow, which is convenient for the water flow transmitted by the inner arc-shaped wing plate 2 to pass through, and can isolate the vortex generated around the single pile foundation, separate the irregular water flow along the pile body, and avoid the formation of a large water flow around the pile body to impact the bottom soil; the bottom of the arc-shaped wing plate 2 is connected to the structure below the soil, and the top is connected to the annular fixing member 3 near the pile foundation, so that the structure above the soil forms a whole and bears the load together.

[0026] 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, one ring of pipe piles and top fixings, two rings of pipe piles and top fixings, and three rings of pipe piles and top fixings; the two rings of fixings are connected to the three rings of fixings through fixing connecting parts, and the top of the pipe piles is the top fixing of each ring.

[0027] 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 fixing parts of each ring to form a whole.

[0028] 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; It is worth noting that the fixing member connecting component 10 is connected to the flow cutoff plate 1 in the structure above the soil.

[0029] 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 positions are 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 arc-shaped wing plate in the structure above the soil is rigidly connected to the structure below the soil; the anti-scouring devices are thus connected as a whole to jointly withstand scouring and load effects.

[0030] In this embodiment, the lengths of the hollow pipe piles 11 in each ring are different, 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 stabilizing function of the outer ring device, so the length of the outer ring pipe pile is greater than that of the inner ring.

[0031] 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 the construction, and has poor economic benefits. After comprehensive consideration, such a structure with a hollow outside and a semi-solid inside was selected. While saving materials and ensuring convenient construction, it takes into account the integrity of the device, anti-scour and vibration reduction performance.

Claims

1. An anti-scouring and vibration reduction device for offshore wind power monopile foundation, characterized in that: The device comprises a flow cutoff plate, an arc-shaped 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, evenly distributed on the fixing member connecting parts of the structure below, and the top is connected to the annular fixing member; the surface of the arc-shaped wing plate is a smooth arc curve, the overall structure is sleeved on the wind power monopile foundation, and a vibration reduction device is embedded in it. Six embedded vibration reduction devices are evenly distributed around the wind turbine monopile 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, 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 monopile foundation, and one end is connected to the mass block; the structure below the soil body includes a plurality of hollow pipe piles, a plurality of ring pipe pile top fixings, and a plurality of fixing connecting parts; 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 pile bodies of the pipe piles are 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 fixings at the top of the third ring pipe piles are connected as a whole by the top fixings; the inner and outer rings are connected by fixing connecting parts; the middle area between the inner and outer rings is soil.

2. The anti-scouring 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 connection between the components is rigid connection.

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

4. The anti-scouring 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-scouring 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 gaskets on the side contacting the pile body to prevent uneven settlement from causing the device to shear the pile body.

6. The anti-scouring 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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