Fan pile foundation anti-scouring device combined with marine economic crop breeding and construction method

Abstract

The invention relates to a fan pile foundation anti-scour device combined with marine commercial crop cultivation and a construction method. The fan pile foundation anti-scour device comprises a pile foundation body, a soil layer is laid on a seabed around the bottom of the pile foundation body, a plurality of layers of cultivation nets are stacked outside the pile foundation body, and each layer of cultivation nets form an anti-scour structure with the pile foundation body as the center and the bottom of the pile foundation body as the center. The diameter of the hollow structure is gradually increased from the top to the bottom; the pile foundation body is sleeved with a fixing ring, a top opening of the hollow structure formed by each layer of cultivation net takes the fixing ring as a starting end, and a bottom opening of the hollow structure is formed in the soil layer. Marine commercial crops such as kelp are bred on the breeding net, the effects of sediment sedimentation and turbulent flow energy dissipation are achieved, and then the effect of reducing pile foundation scouring is achieved; meanwhile, nutritive salt in the water body can be absorbed through growth of crops, certain economic benefits can be obtained through repeated harvesting and cultivation of marine commercial crops, the effect of relieving eutrophication of the water body can be achieved, and reference is provided for anti-scouring design of the offshore wind turbine pile foundation.

Description

Technical Field

[0001] The invention relates to a wind turbine pile foundation anti-scour device combined with marine economic crop breeding and a construction method, belonging to the technical field of offshore wind power engineering. Background Art

[0002] With the development of society, offshore wind power energy has gradually entered the vision of mankind. With the continuous construction and operation of offshore wind farms, problems in wind farms continue to emerge, such as wind turbine pile foundation scouring. For offshore power generation, pile foundations need to solve the instability caused by the loss of sand and soil around the piles caused by wave scouring and seawater corrosion. Therefore, the choice of anti-scouring method for pile foundations will directly affect the maintenance cost after the wind farm is built.

[0003] At present, two methods, riprap protection and horizontal partitions, are mostly used to reduce the scouring of offshore wind turbine pile foundations. For the riprap protection method, its integrity is poor, and the maintenance cost and workload are high during use; for the horizontal partition protection method, due to the strong erosion ability of water flow, as the scouring develops, it is easy to cause scouring damage under the partition. A protective device has also been designed in the prior art. For example, the utility model with application number 201921456168.8 discloses a protective device for offshore wind turbine pile foundation anti-scouring, including a fixed part and a protective part, the fixed part and the protective part are fixedly connected, the fixed part is provided with an outer tube and an inner tube, and cast reinforced concrete is provided between the outer tube and the inner tube, and the protective part is provided with multiple layers of protective cylinders, each layer of the protective cylinder is provided with multiple diversion holes, and the diversion holes of adjacent protective cylinders are staggered.

[0004] Obviously, the existing technologies for improving the anti-scouring ability of wind turbine pile foundations all rely on the installation of protective devices, which raises doubts about the anti-scouring effect and also increases the manufacturing cost. Summary of the invention

[0005] In order to solve the problems in the background technology, the present invention provides a wind turbine pile foundation anti-scour device and a construction method combined with marine economic crop farming.

[0006] The technical solution adopted by the present invention to solve its technical problem is:

[0007] A wind turbine pile foundation anti-scour device combined with marine economic crop farming, comprising a pile base body, a soil layer is laid on the seabed around the bottom, and several layers of farming nets are stacked outside the pile base body, each layer of farming net forms a hollow structure with the pile base body as the center and the diameter gradually increases from the top to the bottom;

[0008] A fixing ring is set on the pile basic body, the top opening of the hollow structure formed by each layer of breeding net takes the fixing ring as the starting end, and the bottom opening of the hollow structure is arranged on the soil layer;

[0009] Define the distance from the top of the breeding net to the bottom of the pile basic body, i.e., the scouring depth, as h; the angle between the inclined surface of the breeding net and the soil layer, i.e., the repose angle, as θ; the radius of the bottom opening of the breeding net, i.e., the distance between the scouring edge and the pile basic body, as R, then R = h / tanθ, where the scouring depth h is 1.0D-1.2D, D is the diameter of the pile basic body, and the repose angle θ is 30°-44°;

[0010] The aquaculture net is used to culture marine cash crops;

[0011] Furthermore, four layers of breeding nets are set, starting from the direction of the pile base, and the bottom diameters of each layer of breeding nets are 2D, 3D, 4D and 5D respectively;

[0012] Furthermore, the soil layer is a silt bottom, and the silt bottom includes clay silt, silt sand and gravel;

[0013] Furthermore, the breeding net includes a net, a net edge and a net frame, the net frame is in a circular ring shape, which is connected to the fixing ring, the net edge is also in a circular ring shape, which is in contact with the soil layer, and the net is arranged between the net frame and the net edge;

[0014] The net is formed by a plurality of mesh wires woven in a crisscross pattern, wherein the transverse mesh wires are parallel to the soil layer, and the longitudinal mesh wires extend from the net frame to the edge of the net;

[0015] Furthermore, several layers of breeding nets are stacked in sequence from the pile base to the outside, and the longitudinal wires of the breeding nets of two adjacent layers are staggered;

[0016] If the longitudinal wires of the breeding nets of two adjacent layers are defined as a and b, with the central axis of the pile basic body as the center line, the position of the longitudinal wire a offset 3°-4° clockwise is the longitudinal wire b;

[0017] Furthermore, a plurality of slots are installed on the circumference of the fixed ring, and a plurality of buckles are installed along the circumference of the net of the breeding net. The slots match the buckles to realize the fixed connection between the fixed ring and the net. When the slots and the buckles are locked, a gap is left between the slots and the buckles.

[0018] Furthermore, a plurality of heavy ballasts are covered along the circumferential edge of the bottom of the outermost layer of the aquaculture net of the pile basic body, and the plurality of heavy ballasts are connected in series through series ropes to form an ecological mat;

[0019] The heavy ballast is sea pebbles or concrete blocks, which are evenly arranged in a matrix around the aquaculture net;

[0020] According to the construction method of the wind turbine pile foundation anti-scour device combined with marine economic crop farming, the method specifically includes the following steps:

[0021] Step S1, laying a soil layer on the seabed around the pile base body;

[0022] Step S2, sleeve a fixing ring on the pile basic body, and install a plurality of slots on the fixing ring;

[0023] Step S3, a circular hole with the same diameter as the pile basic body is opened at the center of the breeding net, the edges of the circular hole are strung together by a mesh, a number of buckles are installed on the mesh, and a number of layers of breeding nets are sleeved on the pile basic body, the mesh of each layer of breeding net is fitted with the pile basic body, and the buckles are embedded in the card slots;

[0024] Step S4, cultivating marine cash crops in batches on the soil layer;

[0025] Step S5, placing a plurality of heavy ballasts at the bottom of the breeding net farthest from the pile basic body, and connecting the plurality of heavy ballasts with series ropes.

[0026] Through the above technical solution, compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The wind turbine pile foundation anti-scour device combined with marine economic crop farming provided by the present invention arranges several layers of staggered farming nets around the pile foundation body, and forms a flexible water barrier by farming marine economic crops (such as kelp), which effectively blocks the lateral flow around the pile foundation and the secondary flow downward on the pile foundation, thereby achieving the effect of sedimentation, disturbing flow and energy dissipation, and further reducing the scour of the pile foundation;

[0028] 2. The wind turbine pile foundation anti-scour device combined with marine economic crop farming provided by the present invention, based on the actual working condition that the pile foundation body is located on the seabed, uses aquaculture nets and marine economic crops such as kelp to achieve the function of dispersing and dissipating energy of upstream water flow, thereby reducing the manufacturing cost of anti-scour. At the same time, the repeated harvesting and farming of marine economic crops further improves the economic benefits;

[0029] 3. The wind turbine pile foundation anti-scour device combined with marine economic crop farming provided by the present invention can absorb nutrients in the water body through the growth of marine economic crops such as kelp, thereby achieving the effect of alleviating eutrophication of the water body. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0031] Figure 1 It is a structural schematic diagram of the preferred embodiment provided by the present invention regarding the actual use of the wind turbine pile foundation anti-scour device;

[0032] Figure 2 It is a schematic structural diagram of a wind turbine pile foundation anti-scour device according to a preferred embodiment of the present invention;

[0033] Figure 3It is a top view of a wind turbine pile foundation anti-scour device according to a preferred embodiment of the present invention;

[0034] Figure 4 It is a front view of a wind turbine pile foundation anti-scour device according to a preferred embodiment of the present invention;

[0035] Figure 5 It is a schematic diagram of a preferred embodiment of the present invention regarding the buckle and the buckle slot being engaged;

[0036] Figure 6 It is a schematic diagram of an ecological mat according to a preferred embodiment of the present invention;

[0037] Figure 7 It is a flow chart of the construction method of the wind turbine pile foundation anti-scour device according to the preferred embodiment provided by the present invention.

[0038] In the figure: 1 is a pile basic body, 2 is a seabed, 3 is a soil layer, 4 is a fixing ring, 5 is a breeding net, 6 is a marine economic crop, 7 is an ecological mat, 8 is a buckle, 9 is a slot, 10 is a concrete block, 11 is a series rope, 12 is a net, 13 is a net edge, and 14 is a net outline. DETAILED DESCRIPTION

[0039] The present invention will now be described in further detail with reference to the accompanying drawings. In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "left side", "right side", "upper part", "lower part", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and "first", "second", etc. do not indicate the importance of the components, and therefore cannot be understood as a limitation on the present invention. The specific dimensions used in this embodiment are only for illustrating the technical solution by example, and do not limit the scope of protection of the present invention.

[0040] As explained in the background technology, the current methods for reducing the scour strength of offshore wind turbine pile foundations include riprap protection, horizontal partitions, and the latest protective devices. Under the premise that the anti-scour effect of these means is unknown, the anti-scour cost is bound to increase. Therefore, considering the actual environment in which the pile foundation is located, the present application provides a wind turbine pile foundation anti-scour device combined with the cultivation of marine economic crops. The marine economic crops here mainly refer to species with longer leaves and larger leaf widths, such as kelp.

[0041] The selection of kelp as the main participant is based on the following considerations: kelp and other ribbon-shaped marine cash crops grow in seawater. When the ocean current passes through, its ribbon-shaped shape will hinder and interfere with the ocean current, reducing the speed of the ocean current and changing the direction of the current; this disturbance of the ocean current can reduce the direct scouring force of the ocean current on the seabed around the wind turbine pile foundation, and reduce the possibility of the seabed soil around the pile foundation being scoured away, thereby protecting the pile foundation. The growth cycle of marine cash crops such as kelp is relatively short and can be planted and harvested repeatedly. Reasonable planning of breeding and harvesting time can ensure that there are always enough marine cash crops around the pile foundation to play an anti-scouring role and achieve a continuous and stable protection effect. At the same time, the harvested marine cash crops such as kelp can bring additional economic benefits. Finally, the vegetation area formed by a large number of marine cash crops can enhance the stability of the marine ecosystem and improve the adaptability of the marine ecosystem to environmental changes.

[0042] like Figure 1 As shown in FIG. 1 , it is a schematic diagram of the overall structure of the wind turbine pile foundation anti-scouring device after cultivating marine economic crops such as kelp provided by the present invention. Obviously, it is also particularly important to build a structure for cultivating and surviving marine economic crops such as kelp. After also considering the anti-scouring effect and cost, as shown in FIG. Figure 2 Shown is a schematic structural diagram of a preferred embodiment of a wind turbine pile foundation anti-scour device.

[0043] It includes a pile basic body 1, a soil layer 3 is laid on the seabed 2 around the bottom, and several layers of aquaculture nets 5 are stacked outside the pile basic body, and each layer of aquaculture nets forms a hollow structure with the pile basic body as the center and the diameter gradually expanding from the top to the bottom. The laying of the soil layer is for the cultivation of different marine cash crops 6. Considering that silt soil can provide good soil conditions for marine cash crops such as kelp, and algae have a significant deposition effect on silt, the silt bottom is selected as the soil layer. The silt bottom includes clay silt, silt and gravel. Marine cash crops such as kelp of different cycles are planted on the soil layers covered by different layers of aquaculture nets, providing good soil conditions for the cultivation of marine cash crops such as kelp. Regarding the "Temple of Heaven"-shaped hollow structure, this design can facilitate each layer of aquaculture net to fully cultivate marine cash crops, stagger the harvesting time of various marine cash crops, ensure that there are always enough plant leaves around the pile basic body, and then play the effect of disturbing flow and eliminating waves, and reduce the scouring of the pile foundation by the incoming flow.

[0044] Of course, the planting density and arrangement spacing of marine economic crops such as kelp will change according to the required wind turbine pile foundation protection effect.

[0045] The breeding net needs to be fixedly connected to the pile basic body, so a fixing ring 4 is sleeved on the pile basic body, and the top opening of the hollow structure formed by each layer of breeding net takes the fixing ring as the starting end, and the bottom opening of the hollow structure is arranged on the soil layer. Preferably, a plurality of slots 9 are installed on the circumference of the fixing ring, and a plurality of buckles 8 are installed along the circumference of the net of the breeding net. The slots and buckles match to realize the fixed connection between the fixing ring and the net, and the fixing ring and the buckle are made of aluminum alloy. When the slots and buckles are locked, a gap is left between the slots and the buckles. Figure 5 The figure shows a schematic diagram of the slot and the buckle after they are embedded. It can be clearly seen from the figure that the slot on the fixing ring is an embedded L-shaped structure, and the buckle is a U-shaped structure with two vertical ends of inconsistent lengths. The short end of the buckle is embedded in the slot. In actual design, a long deformation space is left on the buckle and the slot along the circumferential direction to prevent water erosion.

[0046] The distribution of several layers of aquaculture nets is another innovative point of this application. It has been confirmed through experimental theory that under relatively strong hydrodynamic effects, if the diameter of the pile basic body is defined as D, the balanced scour depth around the pile can generally reach 1.0D-1.2D, and the scour slope angle is generally close to the angle of repose of the riverbed soil. For sandy soil, the repose angle is generally 30°-44°. Therefore, the distance from the top of the aquaculture net to the bottom of the pile basic body, that is, the scour depth, is defined as h, the angle between the inclined surface of the aquaculture net and the soil layer, that is, the angle of repose, is θ, and the radius of the bottom opening of the aquaculture net, that is, the distance between the scour edge and the pile basic body, is R, then R=h / tanθ. The distance between the scour edge and the pile basic body is obtained from the above formula to be 1.73D-2.08D, so the diameter range of the scour pit formed should be 4.46D-5.16D. In actual use, the fixed ring is usually located 1-2 meters above sea level.

[0047] From the dual considerations of anti-scouring effect and economic cost, the present application preferably sets four layers of breeding nets. Starting from the direction of the pile base, the bottom diameters of each layer of breeding nets are 2D, 3D, 4D and 5D respectively.

[0048] After the location of the aquaculture net is determined, the anti-scouring performance is also affected by the specific structure of the aquaculture net itself, which is also one of the innovative points of this application. Figure 3-Figure 4 As shown, the aquaculture net includes a net 12, a net edge 13 and a net 14. The aquaculture net is a polyethylene structure with corrosion resistance. The net is in the shape of a ring and is connected to a fixed ring. The net edge is also in the shape of a ring and is in contact with the soil layer. The net is arranged between the net and the net edge. The net includes a plurality of mesh wires woven in a crisscross pattern, wherein the transverse mesh wires are parallel to the soil layer and the longitudinal mesh wires extend from the net to the net edge. The spacing of the holes formed by the crisscrossing mesh wires can be specifically set according to the planting density of the marine cash crops.

[0049] As mentioned above, the multi-layer design of the aquaculture net is combined with marine economic crops such as kelp to achieve double disturbance and wave elimination. In order to optimize the anti-scouring ability of the aquaculture net, several layers of aquaculture nets are stacked in sequence from the pile basic body to the outside, and the longitudinal mesh wires of the two adjacent layers of aquaculture nets are staggered; the layers of aquaculture nets are staggered with each other to form a flexible water barrier with marine economic crops such as kelp. Specifically, if the longitudinal mesh wires of the two adjacent layers of aquaculture nets are defined as a and b respectively, with the central axis of the pile basic body as the center line, the position of the longitudinal mesh wire a offset by 3°-4° clockwise (of course, counterclockwise is also feasible here) is the longitudinal mesh wire b.

[0050] After the successful cultivation of marine economic crops such as kelp, when the tide carries mud and sand to scour the cultivation net, the plant leaves can disturb the tide, reduce the flow velocity of the tide and cause wave energy loss, which in turn causes an increase in the sedimentation rate of mud and sand in the cultivation net and a weakening of the resuspension process, thus playing an anti-scouring effect.

[0051] In the wind turbine pile foundation anti-scour device combined with marine economic crop farming, Figure 6 As shown, a plurality of heavy ballasts are covered along the circumferential edge of the bottom of the aquaculture net at the outermost layer of the pile basic body, and the plurality of heavy ballasts are connected in series by series ropes 11 to form an ecological mat 7, which is used to fix the aquaculture net and cover the scouring area around the pile basic body. The heavy ballasts are sea pebbles or concrete blocks 10, which are evenly arranged in a matrix around the aquaculture net.

[0052] Finally, the designed wind turbine pile foundation anti-scour device combined with marine economic crop farming needs to be actually constructed and installed. This application fully considers the characteristics of each component and provides corresponding construction methods, such as Figure 7 As shown, the specific steps include:

[0053] Step S1, laying a soil layer on the seabed around the pile base body;

[0054] Step S2, a fixing ring is set on the pile body at a position 1-2 meters above the sea level, and a plurality of slots are installed on the fixing ring;

[0055] Step S3, a circular hole with the same diameter as the pile basic body is opened at the center of the breeding net, the edges of the circular hole are strung together by a mesh, a number of buckles are installed on the mesh, and a number of layers of breeding nets are sleeved on the pile basic body, the mesh of each layer of breeding net is fitted with the pile basic body, and the buckles are embedded in the card slots;

[0056] Step S4, cultivating marine cash crops in batches on the soil layer;

[0057] Step S5, placing a plurality of heavy ballasts at the bottom of the breeding net farthest from the pile basic body, and connecting the plurality of heavy ballasts with series ropes.

[0058] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those generally understood by those skilled in the art to which this application belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless defined as herein.

[0059] The meaning of "and / or" described in this application means that the situations where each exists alone or both exist at the same time are included.

[0060] The term “connection” as used in this application may mean a direct connection between components or an indirect connection between components via other components.

[0061] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A wind turbine pile foundation anti-scour device combined with marine economic crop breeding, characterized by: It includes a pile basic body, a soil layer is laid on the seabed around the bottom, and several layers of aquaculture nets are stacked outside the pile basic body, each layer of aquaculture net forms a hollow structure with the pile basic body as the center and the diameter gradually increases from the top to the bottom; A fixing ring is set on the pile basic body, the top opening of the hollow structure formed by each layer of breeding net takes the fixing ring as the starting end, and the bottom opening of the hollow structure is arranged on the soil layer; Define the distance from the top of the breeding net to the bottom of the pile basic body, i.e., the scouring depth, as h; the angle between the inclined surface of the breeding net and the soil layer, i.e., the repose angle, as θ; the radius of the bottom opening of the breeding net, i.e., the distance between the scouring edge and the pile basic body, as R, then R = h / tanθ, where the scouring depth h is 1.0D-1.2D, D is the diameter of the pile basic body, and the repose angle θ is 30°-44°; The aquaculture net is used to culture marine economic crops.

2. The wind turbine pile foundation anti-scour device combined with marine economic crop breeding according to claim 1 is characterized by: Four layers of breeding nets are set up. Starting from the direction of the pile base, the bottom diameters of each layer of breeding nets are 2D, 3D, 4D and 5D respectively.

3. The wind turbine pile foundation anti-scour device combined with marine economic crop breeding according to claim 1 is characterized by: The soil layer is a silt sand base, which includes clay silt sand, silt sand and gravel.

4. The wind turbine pile foundation anti-scour device combined with marine economic crop breeding according to claim 1 is characterized by: The breeding net includes a net, a net edge and a net frame, the net frame is in a circular ring shape and is connected to a fixing ring, the net edge is also in a circular ring shape and is in contact with the soil layer, and the net is arranged between the net frame and the net edge; The net is formed by a plurality of mesh wires woven in a crisscross pattern, wherein the transverse mesh wires are parallel to the soil layer, and the longitudinal mesh wires extend from the net frame to the edge of the net.

5. The wind turbine pile foundation anti-scour device combined with marine economic crop breeding according to claim 4 is characterized by: Several layers of breeding nets are stacked in sequence from the pile base to the outside, and the longitudinal wires of the breeding nets of two adjacent layers are staggered; If the longitudinal wires of the breeding net in two adjacent layers are defined as a and b respectively, with the central axis of the pile basic body as the center line, the position where the longitudinal wire a is offset 3°-4° clockwise is the longitudinal wire b.

6. The wind turbine pile foundation anti-scour device combined with marine economic crop breeding according to claim 4 is characterized by: A plurality of slots are installed on the circumference of the fixed ring, and a plurality of buckles are installed along the circumference of the net of the breeding net. The slots match with the buckles to realize the fixed connection between the fixed ring and the net. When the slots and the buckles are locked, a gap is left between the slots and the buckles.

7. The wind turbine pile foundation anti-scour device combined with marine economic crop farming according to claim 1 is characterized by: A plurality of heavy ballasts are laid along the circumferential edge of the bottom of the outermost layer of the aquaculture net of the pile basic body, and the plurality of heavy ballasts are connected in series through series ropes to form an ecological mat; The heavy ballast is sea pebbles or concrete blocks, which are evenly arranged around the breeding net in a matrix shape.

8. The construction method of the wind turbine pile foundation anti-scour device combined with marine economic crop breeding according to any one of claims 1 to 7, characterized in that: The specific steps include: Step S1, laying a soil layer on the seabed around the pile base body; Step S2, sleeve a fixing ring on the pile basic body, and install a plurality of slots on the fixing ring; Step S3, a circular hole with the same diameter as the pile basic body is opened at the center of the breeding net, the edges of the circular hole are strung together by a mesh, a number of buckles are installed on the mesh, and a number of layers of breeding nets are sleeved on the pile basic body, the mesh of each layer of breeding net is fitted with the pile basic body, and the buckles are embedded in the card slots; Step S4, cultivating marine cash crops in batches on the soil layer; Step S5, placing a plurality of heavy ballasts at the bottom of the breeding net farthest from the pile basic body, and connecting the plurality of heavy ballasts with series ropes.

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