A pile foundation structure for offshore wind turbine tower

Abstract

This invention provides a pile foundation structure for offshore wind turbine towers, belonging to the field of offshore wind power technology. The pile foundation structure includes a pile cylinder extending vertically along its axis and cast-in-place piles fixedly installed at the bottom of the pile cylinder. The pile cylinder and the cast-in-place piles are coaxially arranged. Each cast-in-place pile includes a pile tube. Multiple support fins extending along the axial direction are fixedly installed on the outer wall of the pile tube, evenly distributed along the circumference of the pile tube. A protective cylinder is slidably sleeved on the outer wall of the pile cylinder. A fixing plate is fixedly sleeved on the outer wall of the pile cylinder, located above the protective cylinder, to limit the movement of the protective cylinder along its axial direction. A protective frame is fixedly sleeved on the bottom of the outer wall of the protective cylinder. The protective frame includes a fixing disc coaxially arranged with the protective cylinder. Two sets of protective components are fixedly installed at the bottom of the fixing disc to prevent the pile cylinder from sinking and tilting due to geological changes after long-term use.

Description

Technical Field

[0001] This invention belongs to the field of offshore wind power technology, specifically relating to a pile foundation structure for offshore wind turbine towers. Background Technology

[0002] Offshore wind power generation is a clean and environmentally friendly method of power generation. The foundation of an offshore wind turbine is crucial in supporting the entire turbine, and many accidents involving offshore wind turbines are caused by unstable foundations. Due to the action of waves and currents, the silt surrounding the foundation will be eroded, forming scour pits that affect the stability of the foundation. Currently, the main anti-scour device for offshore wind turbine foundations is the rock-fill protection method. However, rock-fill protection has poor overall integrity and requires significant maintenance costs and workload. Conventional flexible anti-scour methods typically involve laying bionic aquatic plants, but this method is unsuitable for small-scale applications and is inconvenient to maintain.

[0003] Chinese patent CN117090235B discloses an anti-scour pile foundation and protection method for offshore wind power. The first flexible flow-restricting fan blade on the first flexible cylinder has an angle with the outer surface of the first flexible cylinder and is distributed in a clockwise circular array. The second flexible flow-restricting fan blade on the second flexible cylinder has an angle with the outer surface of the second flexible cylinder and is distributed in a counterclockwise circular array. When installed on the pile foundation alone, the two blades will rotate in opposite directions with the water flow. The overall structure has the functions of shock absorption, tensile strength and energy absorption, and prevents damage when subjected to rapid currents.

[0004] In existing offshore wind turbine tower pile foundation structures, when the flexible cylinder rotates under the action of water flow, the force on the flexible cylinder will act on the pile foundation body during this rotation. When the pile foundation body is continuously subjected to this force transmitted by the rotation of the flexible cylinder for a long time, the cohesive force between the sediment particles and the friction between the sediment and the surface of the pile foundation body will gradually decrease, resulting in gaps between the pile foundation body and the seabed sediment, causing the pile foundation body to loosen and tilt. Summary of the Invention

[0005] The purpose of this invention is to provide a pile foundation structure for offshore wind turbine towers, aiming to solve the problem that in the existing pile foundation structure for offshore wind turbine towers, when the flexible cylinder rotates under the action of water flow, the force it receives will act on the pile foundation body. The pile foundation body is subjected to rotational force for a long time, which will cause gaps between the pile foundation body and the seabed sediment, resulting in the pile foundation body becoming loose and tilting.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a pile foundation structure for offshore wind turbine towers, comprising a pile foundation cylinder extending vertically along its axis and cast-in-place piles fixedly installed at the bottom of the pile foundation cylinder. The pile foundation cylinder and the cast-in-place piles are coaxially arranged. The cast-in-place piles include a pile tube, and the outer wall of the pile tube is fixedly equipped with support fins extending along its axial direction. There are multiple support fins, and the multiple support fins are evenly distributed along the circumference of the pile tube.

[0007] A protective sleeve is slidably fitted onto the outer wall of the pile foundation tube, and a fixing plate is fixedly fitted onto the outer wall of the pile foundation tube. The fixing plate is located above the protective sleeve and is used to limit the movement of the protective sleeve along its axial direction. A protective frame is fixedly fitted onto the bottom of the outer wall of the protective sleeve. The protective frame includes a fixing disk coaxially arranged with the protective sleeve. At least two sets of protective components are fixedly installed at the bottom of the fixing disk. Each set of protective components includes multiple protective fins extending along the axial direction of the fixing disk. The multiple protective fins are evenly distributed along the circumference of the fixing disk, and the multiple sets of protective fins are arranged in a concentric ring coaxial with the fixing disk.

[0008] The beneficial effects of this invention are as follows: By setting up supporting fins, fixing discs, and protective fins, during the installation of the pile foundation structure, the supporting fins are driven into the seabed sediment, thereby increasing the contact area between the cast-in-place pile and the seabed sediment, ensuring the stability of the cast-in-place pile. Driving the protective fins into the seabed sediment allows the fixing disc to contact the seabed. On the one hand, the fixing disc can fix the seabed sediment, preventing it from being washed away by underwater currents, thus ensuring the cohesion between sediment particles and the friction between the sediment and the surface of the pile foundation structure. This avoids gaps between the pile foundation structure and the seabed sediment, preventing loosening and tilting of the pile foundation structure. On the other hand, the fixing disc and protective disc can limit and fix the pile foundation cylinder, preventing the pile foundation cylinder from sinking and tilting due to geological changes after long-term use, thus ensuring the stability and service life of the pile foundation structure.

[0009] The top of the fixed plate has multiple sets of through slots, each set of slots has multiple slots and extends along the circumference of the fixed plate. The multiple sets of through slots are arranged in a concentric ring with the fixed plate as coaxial, and the through slots penetrate the fixed plate.

[0010] The effect is that by setting multiple through channels, when the pile foundation structure is being installed, the seawater located below the fixed plate can flow out through the through channels as the fixed plate moves from the sea surface to the seabed. This reduces the resistance caused by the seawater to the fixed plate during its movement, thereby ensuring the smooth installation of the pile foundation structure.

[0011] A flow guiding mechanism is fixedly installed on the top of the protective frame. The flow guiding mechanism includes at least two fixed inner rings and at least two fixed outer rings. Multiple fixed inner rings and multiple fixed outer rings are all sleeved on the outer wall of the protective cylinder and are coaxially arranged with the protective cylinder. Multiple fixed inner rings and multiple fixed outer rings correspond one to one and are evenly distributed up and down along the axial direction of the protective cylinder. Multiple flow guiding plates are fixedly connected between the corresponding fixed inner rings and fixed outer rings. Multiple flow guiding plates are evenly arranged along the circumference of the fixed inner rings.

[0012] Its effect is that, by setting multiple guide plates, on the one hand, the guide plates can turbulent the rapid flow impacting the pile foundation structure and prevent the rapid flow from scouring the pile foundation structure; on the other hand, the guide plates are made of flexible or elastic materials, which can play a role in shock absorption, tensile strength and energy absorption when the rapid flow impacts the guide plates, avoiding damage under the impact force of the rapid flow, thereby improving the service life of the guide plates.

[0013] The length extension direction of the deflector forms an acute angle with the diameter direction of the fixed outer ring, and the angle is less than 45 degrees.

[0014] The width extension direction of the deflector forms an acute angle with the axial direction of the fixed outer ring, and the angle is less than 45 degrees.

[0015] The effect is that the inclined design of the baffle disperses the impact force of the water flow and reduces the local stress concentration on the baffle. At the same time, the inclined baffle guides the water flow in a specific direction, reducing water separation and vortex formation behind the baffle, thereby reducing the range and intensity of the backflow zone and extending its service life.

[0016] The guide vanes installed on two adjacent fixed inner rings are tilted in opposite directions.

[0017] Its effect is that by tilting the guide plates on two adjacent fixed inner rings in different directions, the water flow in any direction can be obstructed by the guide plates, thereby quickly transforming different flow directions of rapid flow or mainstream into a uniformly diffused slow flow to reduce the impact of scouring.

[0018] The installation height of the deflector at the fixed inner ring end is higher than the installation height at the fixed outer ring end.

[0019] Both the inner and outer rings are equipped with connectors for fixing the baffle.

[0020] Multiple fixing members are fixedly connected between the fixed inner ring and the outer wall of the protective cylinder, which are evenly distributed along the circumference of the fixed inner ring to fix the fixed inner ring. Multiple supporting members are fixedly installed on the top of the fixed plate, which are evenly distributed along its circumference. The top of the supporting members passes through multiple fixed outer rings and is fixedly connected to the fixed outer rings.

[0021] Its effect is that it can securely fix the inner ring, outer ring, and guide vane to the protective cylinder and frame in a stable and reliable manner, effectively preventing the guide vane from detaching from the protective cylinder and frame under the strong impact of the rapid flow.

[0022] There is an angle between the protective fins and the radial direction of the fixed plate, and the degree of this angle is less than 180 degrees. The angles formed by the multiple protective fins and the radial direction of the fixed plate are different.

[0023] Its effect is that by setting up a variety of protective fins with different tilt angles at specific locations, when a rapid flow from different directions comes, these protective fins can fix and buffer the mud and sand with their unique tilt angles, thereby effectively preventing the rapid flow from washing away the mud and sand below the fixing plate.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] 1. By incorporating support fins, fixing discs, and protective fins, the support fins are driven into the seabed sediment during pile foundation installation, increasing the contact area between the cast-in-place pile and the seabed sediment, thus ensuring the stability of the pile. The protective fins are driven into the seabed sediment, allowing the fixing disc to contact the seabed. This serves two purposes: firstly, the fixing disc secures the seabed sediment, preventing it from being washed away by underwater currents, thus maintaining the cohesion between sediment particles and the friction between the sediment and the pile foundation surface. This prevents gaps between the pile foundation and the seabed sediment, which could lead to loosening and tilting of the pile foundation. Secondly, the fixing disc and protective disc limit and fix the pile foundation cylinder, preventing it from sinking or tilting due to geological changes after prolonged use, thereby ensuring the stability and service life of the pile foundation structure.

[0026] 2. By setting multiple guide plates, on the one hand, the guide plates can turbulent the rapid flow impacting the pile foundation structure and prevent the rapid flow from scouring the pile foundation structure; on the other hand, the guide plates are made of flexible or elastic materials, which can play a role in shock absorption, tensile strength and energy absorption when the rapid flow impacts the guide plates, avoiding damage under the impact force of the rapid flow, thereby improving the service life of the guide plates.

[0027] 3. By setting multiple guide plates, on the one hand, the guide plates can turbulently flow through the impacting pile foundation structure, preventing the rapid flow from scouring the pile foundation; on the other hand, the guide plates are made of flexible or elastic materials, which can play a role in shock absorption, tensile strength, and energy absorption when the rapid flow impacts the guide plates, avoiding damage under the impact force of the rapid flow, thereby improving the service life of the guide plates; the inclined setting of the guide plates can disperse the impact force of the water flow, reduce the local stress concentration of the guide plates, and at the same time, the inclined guide plates can guide the water flow in a specific direction, reduce the separation and vortex formation of the water flow behind the plate, thereby reducing the range and intensity of the backflow zone and extending the service life; tilting the guide plates on two adjacent fixed inner rings in different directions can make the water flow in any direction subject to the obstruction effect of the guide plates, thereby quickly transforming the rapid flow or mainstream of different flow directions into a uniformly diffused slow flow, reducing the impact of scouring. Attached Figure Description

[0028] Figure 1 This is a three-dimensional structural diagram of the pile foundation structure in this invention;

[0029] Figure 2 This is a schematic diagram of the main structure of the pile foundation in this invention;

[0030] Figure 3 This is a schematic diagram of the bottom view of the cast-in-place pile in this invention;

[0031] Figure 4 This is a three-dimensional structural diagram of the protective component in this invention;

[0032] Figure 5 This is a schematic diagram of the main structure of the protective component in this invention;

[0033] Figure 6 This is a top view of the protective component in this invention.

[0034] Figure 7 This is a bottom view of the protective component in this invention.

[0035] Figure 8 This is a three-dimensional structural diagram of the flow guiding mechanism in this invention.

[0036] In the diagram: 1. Pile foundation tube; 11. Fixing plate; 2. Cast-in-place pile; 21. Pile tube; 22. Support fin; 3. Protective tube; 4. Protective frame; 41. Fixing plate; 411. Through groove; 42. Protective fin; 5. Flow guiding mechanism; 51. Fixed inner ring; 52. Fixed outer ring; 53. Flow guiding plate; 54. Connector; 55. Support; 56. Fixing component. Detailed Implementation

[0037] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0038] Please see Figures 1-8 The present invention provides the following technical solution: a pile foundation structure for offshore wind turbine towers, including a pile foundation cylinder 1, a cast-in-place pile 2, a protective cylinder 3, a protective frame 4, and a flow guiding mechanism 5.

[0039] refer to Figure 1 As shown, the axis of the pile foundation cylinder 1 extends vertically. The cast-in-place pile 2 is coaxially arranged with the pile foundation cylinder 1 and fixedly installed at the bottom of the pile foundation cylinder 1, its function being to connect with the seabed rock strata. The protective cylinder 3 is also coaxially arranged with the pile foundation cylinder 1 and slidably sleeved onto the outer wall of the pile foundation cylinder 1. The protective frame 4 is fixedly sleeved at the bottom position of the outer wall of the protective frame 3, used to fix the seabed sediment and prevent it from being washed away by the water flow. The flow guiding mechanism 5 is installed on the top of the protective frame 4, its function being to create turbulence when a rapid current passes by, preventing the rapid current from scouring the pile foundation cylinder 1.

[0040] refer to Figure 2 As shown, a fixing plate 11 is fixedly sleeved on the outer wall of the pile foundation cylinder 1. The fixing plate 11 is located above the protective cylinder 3, and its function is to limit the movement of the protective cylinder 3 along the axial direction.

[0041] refer to Figure 3 As shown, the cast-in-place pile 2 includes a pile cylinder 21. Multiple support fins 22 extending along the axial direction are fixedly installed on the outer wall of the pile cylinder 21. These support fins 22 are evenly distributed along the circumference of the pile cylinder 21. The support fins 22 increase the contact area between the pile cylinder 21 and the silt, thereby enhancing the stability of the pile foundation cylinder 1. Simultaneously, before the installation of the device, the support fins 22 also provide support for the protective cylinder 3 and the protective frame 4.

[0042] refer to Figure 5 and Figure 7 As shown, the protective frame 4 includes a fixed disk 41 coaxially arranged with the protective cylinder 3. At least two sets of protective components are fixedly installed at the bottom of the fixed disk 41. Each set of protective components includes multiple protective fins 42 extending along the axial direction of the fixed disk 41. The multiple protective fins 42 are evenly distributed along the circumference of the fixed disk 41. The multiple sets of protective fins 42 are arranged in a concentric ring coaxial with the fixed disk 41. There is an angle between the protective fins 42 and the radial direction of the fixed disk 41, and the degree of the angle is less than 180 degrees. The angles formed by the multiple protective fins 42 and the radial direction of the fixed disk 41 are all different.

[0043] The top of the fixed plate 41 has multiple sets of through slots 411, each set containing multiple slots that extend along the circumference of the fixed plate 41. These slots 411 are arranged in a concentric ring, coaxial with the fixed plate 41, and penetrate the fixed plate 41. During pile foundation installation, the protective fins 42 need to be driven into the seabed sediment. During this process, seawater is discharged from the bottom of the fixed plate 41 through the multiple sets of through slots 411, reducing the resistance from seawater during pile foundation installation.

[0044] refer to Figure 4 , Figure 6 and Figure 8 As shown, the flow guiding mechanism 5 includes a fixed inner ring 51, a fixed outer ring 52, a flow guide plate 53, a connector 54, a support 55, and a fixing member 56.

[0045] There are at least two fixed inner rings 51 and at least two fixed outer rings 52. Multiple fixed inner rings 51 and multiple fixed outer rings 52 are fitted onto the outer wall of the protective cylinder 3 and are coaxially arranged with the protective cylinder 3. Multiple fixed inner rings 51 and multiple fixed outer rings 52 correspond one to one and are evenly distributed up and down along the axial direction of the protective cylinder 3.

[0046] Multiple guide vanes 53 are installed between multiple corresponding fixed inner rings 51 and fixed outer rings 52. Both ends of each guide vane 53 are fixedly connected to the corresponding fixed inner ring 51 and fixed outer ring 52 via connectors 54. The multiple guide vanes 53 are evenly arranged along the circumference of the fixed inner ring 51. The guide vanes 53 are made of flexible or elastic materials, thus playing a role in shock absorption, tensile strength, and energy absorption, preventing damage when subjected to rapid flow impact.

[0047] The length extension direction of the guide vane 53 forms an acute angle with the diameter direction of the fixed outer ring 52, and this angle is less than 45 degrees; the width extension direction of the guide vane 53 also forms an acute angle with the axial direction of the fixed outer ring 52, and this angle is less than 45 degrees. The guide vanes 53 installed on two adjacent fixed inner rings 51 have opposite inclination directions, and the installation height of the guide vane 53 at one end of the fixed inner ring 51 is higher than its installation height at one end of the fixed outer ring 52.

[0048] There are multiple support members 55, which are fixedly installed on the top of the fixed disk 41 and evenly distributed along the circumference of the fixed disk 41. The top of the support member 55 passes through multiple fixed outer rings 52 and is fixedly connected to the fixed outer rings 52. The support member 55 is a support column or a support plate.

[0049] There are multiple fasteners 56, which are located between multiple inner rings 51 and the outer wall of the protective cylinder 3. The multiple fasteners 56 on each inner ring 51 are evenly distributed along the circumference of the inner ring 51. The fasteners 56 are connecting posts or connecting plates, and their two ends are fixedly connected to the inner ring 51 and the outer wall of the protective cylinder 3, respectively.

[0050] The implementation principle of this invention is as follows: When installing the pile foundation structure, the pile cylinder 1 and the cast-in-place pile 2 are placed at a predetermined position on the seabed along their axial direction. Then, external force is applied to drive the cast-in-place pile 2 into the seabed sediment. At this time, the support fins 22 are also inserted into the sediment simultaneously, thereby increasing the contact area between the pile cylinder 21 and the sediment and increasing the stability of the pile cylinder 21.

[0051] Pressure is continued to be applied to the pile foundation cylinder 1, causing it to sink into the sediment. At this time, the protective fins 42 at the bottom of the fixing plate 41 contact the seabed, driving the protective cylinder 3, protective frame 4, and flow guiding mechanism 5 to slide upwards along the axis of the pile foundation cylinder 1 until the top of the protective cylinder 3 contacts the fixing plate 11. As the pile foundation cylinder 1 continues to sink, the protective fins 42 are pressed into the seabed sediment until the fixing plate 41 contacts the seabed. At this point, the protective fins 42 are inserted into the sediment, making the fixing plate 41 adhere tightly to the seabed, thus fixing the fixing plate 41. This also allows the protective frame 4 to fix the sediment, preventing it from being washed away. At the same time, the protective cylinder 3 can limit the position of the pile foundation cylinder 1, preventing it from sinking and tilting due to geological changes after long-term use. Then, counterweights such as stones are placed on top of the fixing plate 41 to further increase the stability of the pile foundation structure.

[0052] Although embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present invention.

Claims

1. A pile foundation structure for an offshore wind turbine tower, comprising a pile foundation cylinder extending in vertical direction along an axis and a cast-in-place pile fixedly mounted at the bottom of the pile foundation cylinder, the pile foundation cylinder and the cast-in-place pile being coaxially arranged, characterized in that A cast-in-place pile includes a pile cylinder, and the outer wall of the pile cylinder is fixedly equipped with support fins extending along its axial direction. There are multiple support fins, and the multiple support fins are evenly distributed along the circumference of the pile cylinder. A protective sleeve is slidably fitted onto the outer wall of the pile foundation tube, and a fixing plate is fixedly fitted onto the outer wall of the pile foundation tube. The fixing plate is located above the protective sleeve and is used to limit the movement of the protective sleeve along its axial direction. A protective frame is fixedly fitted onto the bottom of the outer wall of the protective sleeve. The protective frame includes a fixing disk coaxially arranged with the protective sleeve. At least two sets of protective components are fixedly installed at the bottom of the fixing disk. Each set of protective components includes multiple protective fins extending along the axial direction of the fixing disk. The multiple protective fins are evenly distributed along the circumference of the fixing disk and are arranged in a concentric ring coaxial with the fixing disk. A flow guiding mechanism is fixedly installed on the top of the protective frame. The flow guiding mechanism includes multiple fixed inner rings and multiple fixed outer rings. The multiple fixed inner rings and multiple fixed outer rings are sequentially fitted onto the protective cylinder and are coaxially arranged with the protective cylinder. The multiple fixed inner rings and multiple fixed outer rings correspond one to one and are evenly distributed up and down along the axial direction of the protective cylinder. Multiple flow guiding plates are fixedly connected between the corresponding fixed inner rings and fixed outer rings. The multiple flow guiding plates are evenly arranged along the circumferential direction of the fixed inner ring. The length extension direction of the deflector forms an acute angle with the diameter direction of the fixed outer ring, and the angle is less than 45 degrees.

2. A pile foundation structure for an offshore wind turbine tower according to claim 1, characterized in that: The top of the fixed disk has multiple sets of through slots, each set of through slots has multiple slots and extends along the circumference of the fixed disk. The multiple sets of through slots are arranged in a concentric ring with the fixed disk as coaxial, and the through slots penetrate the fixed disk.

3. A pile foundation structure for an offshore wind turbine tower according to claim 1, characterized in that: The width extension direction of the guide plate forms an acute angle with the axial direction of the fixed outer ring, and the angle is less than 45 degrees.

4. The pile foundation structure for offshore wind turbine towers according to claim 3, characterized in that: The guide vanes installed on the two adjacent fixed inner rings are tilted in opposite directions.

5. The pile foundation structure for offshore wind turbine towers according to claim 4, characterized in that: The installation height of the guide plate at one end of the fixed inner ring is higher than the installation height at one end of the fixed outer ring.

6. The pile foundation structure for offshore wind turbine towers according to claim 5, characterized in that: Both the fixed inner ring and the fixed outer ring are equipped with connectors for fixing the guide plate.

7. The pile foundation structure for offshore wind turbine towers according to claim 1, characterized in that: Multiple fixing members are fixedly connected between the fixed inner ring and the outer wall of the protective cylinder, which are evenly distributed along the circumference of the fixed inner ring to fix the fixed inner ring. Multiple supporting members are fixedly installed on the top of the fixed plate, which are evenly distributed along its circumference. The top of the supporting members passes through multiple fixed outer rings and is fixedly connected to the fixed outer rings.

8. The pile foundation structure for offshore wind turbine towers according to claim 1, characterized in that: There is an angle between the protective fins and the radial direction of the fixed disk, and the degree of the angle is less than 180 degrees. The angles formed by the multiple protective fins and the radial direction of the fixed disk are different.

Images