Impact-preventing siltation-promoting fixing device for offshore platform pile foundation

Abstract

The invention discloses an anti-scour siltation promotion fixing device for an offshore platform pile foundation, which is provided with an inner pile casing, an outer pile casing, a protective ring and a bottom plate, siltation holes and flow blocking thorns are arranged in the outer pile casing, and grids are arranged in the bottom plate; the inner pile casing and the outer pile casing are connected through the connecting rod, and the protective ring and the bottom plate are sequentially connected to the lower end of the outer pile casing. The scour prevention and siltation promotion device is installed outside the pile foundation. The device has the functions of scour prevention and siltation promotion, silt in the device can be deposited, the protection effect on a pile foundation and the device is achieved, the device has the function of preventing seabed scour, the stability of the device can be improved through silt deposition in the device, and the device can be effectively prevented from being scoured again by ocean currents. The pile foundation is simple in structure and reasonable in design, can play an effective role in scour prevention and siltation promotion around the pile foundation, and is suitable for all ocean engineering platform pile foundations, such as offshore oil platforms, wind power platforms and other ocean engineering platforms.

Description

Technical Field

[0001] The invention relates to protective equipment for pile foundations in nearshore and marine engineering projects, and in particular to an anti-scouring and silting-promoting fixing device for offshore platform pile foundations. Background Art

[0002] Offshore oil platforms are a major structural form in offshore engineering. Seabed scour is a common phenomenon near the platform pile foundations. After the platform foundation is constructed in the seabed, the coupled effects of waves and currents cause the streamlines of water particles near the pile foundation to change. This sudden change in streamlines increases the shear stress on the soil particles on the seabed surface, causing scour around the pile foundation. Scour reduces the buried depth of the pile foundation and increases the cantilever length of the platform structure, thereby reducing the bearing capacity of the pile foundation, increasing the overturning moment of the pile foundation and the horizontal displacement of the platform wind turbine, seriously affecting the stability of the platform structure. Furthermore, scour of the platform foundation can reduce the natural frequency of the pile structure, increase the fatigue stress amplitude, and increase the number of stress cycles, thus affecting the fatigue life of the platform as a whole. Therefore, preventing scour from ocean currents and promoting sediment accumulation around the platform pile foundation is particularly important for the stability of offshore oil platforms.

[0003] Pile foundation scour protection has become one of the key technologies in offshore oil platform construction. Based on the platform structure and the principle of pile foundation scour protection, offshore oil platform pile foundation scour protection measures can be divided into the following categories: (1) No protection scheme: No anti-scouring measures are taken, but compensation is made by increasing the stiffness of the pile foundation.

[0004] (2) Passive protection: Reduce the scouring of the platform foundation by increasing the seabed's ability to resist water shear, such as laying protective materials on the seabed around the pile foundation or solidifying the seabed soil.

[0005] (3) Active protection: By setting up various forms of flow disturbance structures around the platform pile foundation, such as guard rings, baffles, pile foundation slits or pile rows, the water flow characteristics are changed to reduce the scouring effect, disrupt the flow field of the ocean current around the pile foundation, and weaken the erosion ability of the water flow on the seabed around the pile foundation, thereby reducing the scouring of the seabed surface. The active protection scheme directly solves the problem from the perspective of the cause of the scouring process, so its protection efficiency is higher than that of the passive protection scheme.

[0006] Overall, while passive protection solutions such as riprap, sand blankets, and soil consolidation have been widely used in engineering practice, they are time-consuming, costly, and potentially harmful to the pile foundation during construction. Active protection, which modifies flow characteristics through retaining rings, baffles, pile foundation cracks, or pile rows, is less commonly used in marine structures due to the current lack of robust and adaptable active protection devices.

[0007] A search revealed the following patent: Patent application number 201410479851.9 discloses a method for pile foundation scour protection, which combines a pre-pile row of piles and a retaining ring around the pile group. The pre-pile row of piles is positioned in front of the pile group to deflect the direction of high-speed water flow in front of the pile group, reduce the water velocity in the wake area of ​​the pile group, and reduce the turbulence intensity of the vortex system around the pile group. The retaining ring around the pile group is a wheel retaining ring installed on at least one row of piles facing the water flow in the pile group to reduce the intensity of the descending water flow and horseshoe-shaped vortex. The piles are arranged in a herringbone or arc shape, with the corresponding angle or center of the circle facing the direction of the pile group's incoming flow axis. This method improves the reliability of pile foundation scour protection and enhances the stability and safety of infrastructure such as bridges and offshore platforms. Furthermore, the method is convenient to construct and highly practical. No subsequent maintenance is required after implementation, which greatly reduces the workload, saves time and effort, and reduces the consumption of manpower and materials, resulting in high economic efficiency.

[0008] However, the above invention method can only improve the scour protection effect of the pile foundation and can only weaken the intensity of the descending water flow and the horseshoe-shaped vortex through the wheel guard ring, but cannot enhance the stability of the device itself and the pile foundation.

[0009] Application No. 202111218935.3 provides a new type of pile foundation anti-scour protection structure and its construction method, the structure includes geotextile, riprap layer and mold bag concrete, the geotextile is laid flat on the riverbed or seabed around the steel pipe pile foundation to reduce the flow of bed sediment and gravel around the pile foundation; the riprap layer is laid on the upper part of the geotextile within the scour pit around the pile foundation to fill the scour pit around the pile foundation; the mold bag concrete is located on the upper part of the geotextile and the riprap layer, and concrete or cement mortar is poured into the mold bag by a high-pressure pump. After solidification, a mold bag concrete overall structure with a certain strength is formed. The above invention is convenient to construct, has good application effect and strong adaptability, and can be widely used in the pile foundation protection of structures such as cross-sea bridges, offshore platforms and offshore wind power. Each protective layer fits tightly and has good integrity, which can effectively improve the anti-scour ability.

[0010] While the aforementioned invention offers strong scour resistance, with the top layer of bagged concrete solidifying to form a relatively strong overall bagged concrete structure, combined with the previously laid geotextile and riprap layers, it forms a rigid plate-like scour barrier that adheres to the seabed and fits tightly to the pile foundation, preventing scour points and effectively resisting wave damage. However, the project still suffers from the drawbacks of being time-consuming and costly, as well as potentially damaging to the pile foundation itself.

[0011] Therefore, proposing a pile foundation protection device with high protection efficiency and strong adaptability is one of the problems to be solved in the design and construction of offshore platforms. Summary of the Invention

[0012] In view of the shortcomings of the existing technology, in order to prevent the seabed around the pile foundation of the offshore engineering platform from being scoured by the combined action of shallow water wave effect and bottom current disturbance, an anti-scouring and sedimentation-promoting fixing device for the offshore platform pile foundation is provided to accelerate the sedimentation of sediment particles in the sand-laden water flow around the pile foundation, so as to improve the protection effect of the platform pile foundation and enhance the stability of the platform pile foundation.

[0013] To solve the above technical problems, the present invention adopts the following technical solutions: an anti-scouring and sedimentation-promoting fixing device for offshore platform pile foundations, comprising an inner casing, an outer casing, a protective ring, and a bottom plate; the outer casing is provided with silt collection holes and flow-blocking spikes, and the bottom plate is provided with a grid; the inner casing and the outer casing are connected by a connecting rod, and the protective ring and the bottom plate are sequentially connected to the lower end of the outer casing; The anti-scouring and sedimentation-promoting device is installed outside the pile foundation.

[0014] Preferably, the silt collection holes distributed in the outer casing body are through-holes in the form of tapered holes, with the small diameter end of the silt collection holes being located inside the outer casing and the large diameter end being located outside the outer casing; The diameter of the large diameter end of the silt collection hole is 2-3 times that of the small diameter end; The silt collection holes have the same diameter and are staggered in the outer casing, or have different diameters and are arranged in mixed intervals in the outer casing.

[0015] Preferably, the flow-blocking thorns in the outer casing are transverse and irregularly fixed in the barrel of the outer casing; the flow-blocking thorns can be cylindrical rods with consistent outer diameters, or can be conical rods with sharp ends, or a mixture of cylindrical rods with consistent outer diameters and conical rods with sharp ends and irregularly arranged in the outer casing; when the flow-blocking thorns are conical rods, the flow-blocking thorns located on the inner side of the outer casing are cylindrical and the flow-blocking thorns located on the outer side of the outer casing are conical rods; the flow-blocking thorns are made of steel bars and coated with anti-rust paint.

[0016] Preferably, the number of flow-blocking thorns distributed in the outer casing is 1-2 times the number of silt collection holes and is coated with anti-rust paint; the length of the flow-blocking thorns is more than 0.3 times the diameter of the pile foundation.

[0017] Preferably, the base plate is a square plate with a pile foundation mounting hole in the center of the plate, and the grids are evenly distributed in the base plate around the pile foundation mounting hole; the grids are through circular holes or rectangular grooves, and the porosity of the grids in the base plate can be adjusted.

[0018] Preferably, the protective ring is a conical ring and there are no grids or holes on the surface and inside of the ring; the upper end of the outer protective ring is connected to the lower end of the outer casing, and the lower end is connected to the bottom plate; the angle between the outer protective ring and the bottom plate is set between 35 degrees and 70 degrees.

[0019] Preferably, the inner casing is made of stainless steel, the thickness of the inner casing is less than that of the outer casing and no holes of any kind are provided in the cylinder of the inner casing; the inner wall structure and size of the inner casing are consistent with the outer wall structure and size of the pile foundation and can be installed outside the pile foundation.

[0020] Preferably, there are two or more connecting rods connected between the inner casing and the outer casing, and the connecting rods are made of high-strength, corrosion-resistant steel bars and coated with anti-rust paint; the connecting rods can also be vertically welded to the outer wall of the inner casing.

[0021] Preferably, the outer casing, protective ring and base plate are all cast with concrete and steel plates are fixed on the outer surfaces of the outer casing, protective ring and base plate and anti-rust paint is applied on the steel plates; the inner casing, outer casing, protective ring and base plate are all split structures, and the steel plates fixed on the outer surfaces of the outer casing, protective ring and base plate are all provided with wing edges and can be fixed together by wing edges and bolts.

[0022] Preferably, the bottom plate can be placed above the seabed or buried in the seabed, and the bottom of the steel plate on the lower end surface of the bottom plate can also be processed with anti-slip serrations.

[0023] Compared with the prior art, the present invention has the following remarkable effects: 1. The present invention has a simple structure and reasonable design, and can effectively prevent erosion and promote sedimentation around the pile foundation. It is suitable for all marine engineering platform pile foundations, such as offshore oil platforms, wind power platforms and other marine engineering platforms.

[0024] 2. The present invention has good overall performance, low maintenance cost, high practicality, no risk of damage to the pile foundation during installation and use, and can be disassembled or modified.

[0025] 3. The device has the function of preventing erosion and promoting sedimentation, which can cause sedimentation inside the device to achieve protection for the pile foundation and the device itself, and has the function of preventing seabed erosion. The sedimentation inside the device will improve the stability of the device and can effectively prevent the ocean current from eroding the device again.

[0026] 4. The device of the present invention is provided with a number of vertical grids and transverse silt collection holes, which are beneficial to the activities of marine organisms and the transportation of marine substances, and can reduce the impact on the marine environment around the pile foundation.

[0027] In summary, the present invention has significant use effect and application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings: Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention; Figure 2 It is a front view of the planar structure of the present invention; Figure 3 yes Figure 2 A top view of Figure 4 yes Figure 2 sectional view of In the figure: inner casing 1, connecting rod 2, silt collection hole 3, outer casing 4, flow-blocking thorn 5, protective ring 6, bottom plate 7, grid 8, seabed 9, pile foundation 10, pile foundation installation hole 11, wing edge 12. DETAILED DESCRIPTION

[0029] The accompanying drawings are for reference and illustration purposes only and are not intended to limit the scope of protection of the present invention. The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0031] In the description of the present invention, it should be understood that the terms "length," "width," "up," "down," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inside," "outside," and the like, indicating positions or location relationships, are based on the positions or location relationships shown in the accompanying drawings and are intended only to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limiting the present invention. Furthermore, in the description of the present invention, "plurality" means two or more, unless otherwise expressly and specifically defined.

[0032] See also Figure 1 - Figure 4 A device for preventing erosion and promoting sedimentation of an offshore platform pile foundation is provided, which comprises an inner casing 1, an outer casing 4, a protective ring 6 and a bottom plate 7. The outer casing 4 is provided with silt collection holes 3 and flow-blocking thorns 5, and the bottom plate 7 is provided with a grid 8; the inner casing 1 and the outer casing 4 are connected by a connecting rod 2, and the protective ring 6 and the bottom plate 7 are sequentially connected to the lower end of the outer casing 4; the device for preventing erosion and promoting sedimentation is installed on the outside of the pile foundation 10.

[0033] The present invention has a simple structure and can be installed outside the offshore platform pile foundation. Since the outer casing 4 is provided with silt collection holes 3 and flow-blocking spikes 5 and the inner casing 1 is connected to the outer casing 4 by a connecting rod 2, a sand annulus is formed between the inner casing 1 and the outer casing 4.

[0034] When the ocean current carrying silt washes over the device of the present invention, the flow-blocking thorns 5 in the outer casing 4 attenuate the impact force of the ocean current, effectively consume the kinetic energy of the water body, and weaken the strength of the horseshoe vortex near the pile foundation 10; when the silt in the ocean current rushes onto the outer casing 4, part of the silt enters the sedimentation annulus formed between the inner casing 1 and the outer casing 4 through the silt accumulation holes 3 and settles at the bottom of the protective ring 6. The inner casing 1, the outer casing 4 and the protective ring 6 together constitute a sedimentation space, which can effectively enhance the stability of the device and the pile foundation 10.

[0035] The grid 8 on the bottom plate 7 can ensure that the water pressure between the sedimentation space above the device of the present invention and the surface of the seabed 9 below is connected. The device is independent of the pile foundation 10 and is located above the surface of the seabed 9 or the bottom plate 7 is buried below the surface of the seabed 9, and other components are located above the surface of the seabed 9. ， This effectively protects pile foundation 10. By adjusting the length of connecting rod 2, the gap in the sediment annulus between inner casing 1 and outer casing 4 can be controlled. This annulus acts as a slow-flow area, allowing sediment to settle and accumulate above bottom plate 7 and on the seabed 9. The outer casing 4 and protective ring 6 together isolate the inner and outer flow fields, providing protection for pile foundation 10.

[0036] Based on the above embodiment 1, the present invention also has the following embodiments: A preferred embodiment: the silt collection holes 3 distributed in the outer casing 4 are through-holes with a tapered shape, the small diameter end of the silt collection hole 3 is arranged on the inner side of the outer casing 4 and the large diameter end is arranged on the outer side of the outer casing 4; The diameter of the large-diameter end of the sediment collection holes 3 is 2-3 times that of the small-diameter end. These sediment collection holes 3 may have the same diameter and be staggered within the outer casing 4, or may have different diameters and be interspersed within the outer casing 4. The sediment collection holes 3 within the outer casing 4 may be of a single diameter or a mix of multiple diameters. This allows some small-diameter sand particles to enter the sedimentation annulus between the inner casing 1 and the outer casing 4 through the sediment collection holes 3, while some large-diameter sand particles are blocked and fall outside the outer casing 4. Both sand particles that enter the sedimentation annulus and settle at the bottom of the protective ring 6 and sand particles that slide off the outer casing 4 and settle on the bottom plate 7 enhance the stability of the device and the platform pile foundation.

[0037] A preferred embodiment: the flow-blocking thorns 5 in the outer casing 4 are transverse and irregularly fixed in the cylinder of the outer casing 4; the flow-blocking thorns 5 can be cylindrical rods with consistent outer diameters, or can be conical rods with sharp ends, or a mixture of cylindrical rods with consistent outer diameters and conical rods with sharp ends and irregularly arranged in the outer casing 4; when the flow-blocking thorns 5 are conical rods, the flow-blocking thorns 5 located on the inner side of the outer casing 4 are cylindrical and the flow-blocking thorns 5 located on the outer side of the outer casing 4 are conical rods; the flow-blocking thorns 5 are made of steel bars and coated with anti-rust paint.

[0038] The flow-blocking spikes 5 can be rod-shaped and of various structures and specifications, and are irregularly distributed on both the inner and outer sides of the outer casing 4. They can disrupt the internal flow field of the outer casing 4 and reduce the velocity of the ocean current in the sedimentation annulus, thereby promoting sediment deposition and achieving the goal of promoting sedimentation. At the same time, they can disrupt the horseshoe vortex around the outer casing 4, reducing the impact of ocean currents on the device and pile foundation 10 of the present invention. The irregular distribution of the flow-blocking spikes 5 has a more significant effect on disrupting the flow field.

[0039] A preferred embodiment: the number of the flow-blocking thorns 5 distributed in the outer casing 4 is 1-2 times the number of the silt collection holes 3 and is coated with anti-rust paint; the length of the flow-blocking thorns 5 is more than 0.3 times the diameter of the pile foundation 10.

[0040] In a preferred embodiment, the base plate 7 is a square plate with a pile foundation mounting hole 11 in the center. Grids 8 are evenly distributed in the base plate 7 around the pile foundation mounting hole 11. The grids 8 are through-holes or rectangular slots, and the porosity of the grids 8 in the base plate 7 can be adjusted. The grids 8 not only help to settle falling sand but also facilitate the activity of marine organisms and the transport of substances in the water flow.

[0041] A preferred embodiment: the protective ring 6 is a conical ring and there are no grids or holes on the surface and inside of the ring body, which keeps the bottom of the device isolated from the external flow field environment and prevents the sediment deposited below from being washed away again; the upper end of the outer protective ring 6 is connected to the lower end of the outer casing 4, and the lower end is connected to the bottom plate 7; the angle between the outer protective ring 6 and the bottom plate 7 is set between 35 degrees and 70 degrees, the bottom diameter of the protective ring 6 is larger than its top diameter, and the sediment blocked outside the outer casing 4 can slide down onto the bottom plate 7, and the conical ring is more conducive to the formation of sediment deposition; the upper end of the protective ring 6 is connected to the outer casing 4, the lower end is connected to the bottom plate 7, and an angle between the bottom plate 7 and the outer casing 4 is set between 35 degrees and 70 degrees, which expands the sedimentation space inside the device.

[0042] In a preferred embodiment, the inner casing 1 is made of stainless steel, is thinner than the outer casing 4, and contains no holes of any kind. The inner wall structure and dimensions of the inner casing 1 match those of the outer wall of the pile foundation 10 and can be installed outside the pile foundation 10. If the outer wall of the pile foundation 10 is square, the inner wall of the inner casing 1 will also be square; if the outer wall of the pile foundation 10 is circular, the inner wall of the inner casing 1 will also be circular. The inner casing 1 in this device is installed tightly against the pile foundation 10, providing protection for the pile foundation 10.

[0043] In a preferred embodiment, two or more connecting rods 2 are provided between the inner casing 1 and the outer casing 4. The connecting rods 2 are made of high-strength, corrosion-resistant steel bars and coated with anti-rust paint. The connecting rods 2 can also be vertically welded to the outer wall of the inner casing 1 to reinforce and support the inner casing 1. The high-strength, corrosion-resistant steel bars are grade 3 or 4 high-strength chloride-corrosion-resistant steel bars, such as HRB400cE and HRB500cE.

[0044] A preferred embodiment: the outer casing 4, protective ring 6 and bottom plate 7 are all cast with concrete and steel plates are fixed on the outer surfaces of the outer casing 4, protective ring 6 and bottom plate 7 and anti-rust paint is applied on the steel plates to protect the integrity of the device to the greatest extent so that it can provide the best protection for the pile foundation 10; the inner casing 1, outer casing 4, protective ring 6 and bottom plate 7 are all split structures, and the steel plates fixed on the outer surfaces of the outer casing 4, protective ring 6 and bottom plate 7 are all provided with wing edges 12 and can be fixed together by the wing edges 12 and bolts, which is convenient for divers to install and construct on the seabed. Figure 1 - Figure 4 The cross circles in the figure represent bolts, which are located in the bolt holes 12 in the steel plates on the outer surfaces of the outer casing 4, protective ring 6, and base plate 7. They are used to connect and secure the split outer casing 4, protective ring 6, and base plate 7. As shown in the figure, the position and number of bolts in the figure only represent the connection positions of the split outer casing 4, protective ring 6, and base plate 7, and do not limit the number of bolts. Of course, the device can also be manufactured as a whole on land, and the diameter of the pile foundation mounting holes 11 in the inner casing 1 and base plate 7 can be larger than the outer diameter of the pile foundation 10. During construction, the device can be hoisted from the top of the pile foundation 10 to the outside of the bottom of the pile foundation 10 by a floating crane.

[0045] A preferred embodiment: the bottom plate 7 can be placed above the seabed 9 or buried in the seabed 9. The bottom of the steel plate on the lower end surface of the bottom plate 7 can also be processed with anti-slip serrations, which are not shown in the figure. They can cut into the interior of the seabed 9, increase the friction between the device and the seabed 9, further stabilize the foundation of the device, and prevent the device from being displaced under the action of strong current impact.

[0046] In summary, the present invention, fixed around the pile foundation 10 of an offshore engineering platform and laid on the seabed 9 or with the bottom plate 7 buried in the seabed 9, can effectively enhance the strength of offshore engineering structures exposed to multi-directional ocean currents and reduce the scouring force on the offshore platform's pile foundation 10 caused by the combined effects of shallow water waves and bottom current disturbances. Furthermore, the multiple silt collection holes 3, grids 8, and flow-blocking spikes 5 all act to slow the flow, effectively storing sediment carried by the water flow, causing it to settle and promoting siltation, thereby enhancing the stability of the pile foundation 10.

[0047] The embodiments described above are merely typical embodiments, but the present invention is not limited to these embodiments, and those skilled in the art can make modifications without departing from the spirit and enlightenment of the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. Any modifications, equivalent replacements, improvements, etc. made within the creative spirit and creative concept of the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection is not limited to the above description.

Claims

1. An anti-scouring and sedimentation-promoting fixing device for offshore platform pile foundations, characterized by: An inner casing (1), an outer casing (4), a protective ring (6) and a bottom plate (7) are provided. The outer casing (4) is provided with a silt collection hole (3) and a flow-blocking thorn (5), and the bottom plate (7) is provided with a grid (8). The inner casing (1) and the outer casing (4) are connected by a connecting rod (2), and the protective ring (6) and the bottom plate (7) are sequentially connected to the lower end of the outer casing (4). The anti-scouring and silting-promoting device is installed outside the pile foundation (10).

2. The anti-scouring and sedimentation-promoting fixing device for offshore platform pile foundation according to claim 1 is characterized in that: The silt accumulation holes (3) in the outer casing (4) are through-holes of tapered shape. The small diameter end of the silt accumulation holes (3) is arranged on the inner side of the outer casing (4) and the large diameter end is arranged on the outer side of the outer casing (4). The diameter of the large diameter end of the silt accumulation holes (3) is 2-3 times the diameter of the small diameter end. The silt accumulation holes (3) have the same diameter and are staggered in the outer casing (4) or have different diameters and are arranged in mixed intervals in the outer casing (4).

3. The anti-scouring and sedimentation-promoting fixing device for offshore platform pile foundations according to claim 2, characterized in that: The flow-blocking thorns (5) in the outer casing (4) are transversely and irregularly fixed in the barrel of the outer casing (4); the flow-blocking thorns (5) can be cylindrical rods with a uniform outer diameter, or can be tapered rods with a sharp end, or a mixture of cylindrical rods with a uniform outer diameter and tapered rods with a sharp end, and are irregularly arranged in the outer casing (4); when the flow-blocking thorns (5) are tapered rods, the flow-blocking thorns (5) located inside the outer casing (4) are cylindrical and the flow-blocking thorns (5) located outside the outer casing (4) are tapered rods; the flow-blocking thorns (5) are made of steel bars and coated with anti-rust paint.

4. The anti-scouring and sedimentation-promoting fixing device for offshore platform pile foundation according to claim 2 or 3, characterized in that the distribution The number of the flow-blocking thorns (5) in the outer casing (4) is 1-2 times the number of the silt collection holes (3) and is coated with anti-rust paint; the length of the flow-blocking thorns (5) is more than 0.3 times the diameter of the pile foundation (10).

5. The anti-scouring and sedimentation-promoting fixing device for offshore platform pile foundations according to claim 4, characterized in that: The bottom plate (7) is a square plate body and a pile foundation installation hole (11) is provided at the center of the plate body. The grids (8) are evenly distributed in the bottom plate (7) around the pile foundation installation hole (11). The grids (8) are through-holes or rectangular slots. The porosity of the grids (8) in the bottom plate (7) can be adjusted.

6. The anti-scouring and sedimentation-promoting fixing device for offshore platform pile foundations according to claim 5, characterized in that: The protective ring (6) is a conical ring and has no grids or holes on the surface or inside of the ring body; the upper end of the outer protective ring (6) is connected to the lower end of the outer protective tube (4), and the lower end is connected to the bottom plate (7); the angle between the outer protective ring (6) and the bottom plate (7) is set between 35 degrees and 70 degrees.

7. The anti-scouring and sedimentation-promoting fixing device for offshore platform pile foundations according to claim 6, characterized in that: The inner casing (1) is made of stainless steel, the thickness of the inner casing (1) is less than the thickness of the outer casing (4), and no holes of any form are provided in the barrel of the inner casing (1); the inner wall structure and size of the inner casing (1) are consistent with the outer wall structure and size of the pile foundation (10) and can be installed outside the pile foundation (10).

8. The anti-scouring and sedimentation-promoting fixing device for offshore platform pile foundations according to claim 7, characterized in that: Two or more connecting rods (2) are provided between the inner casing (1) and the outer casing (4); the connecting rods (2) are made of high-strength, corrosion-resistant steel bars and coated with anti-rust paint; the connecting rods (2) can also be vertically welded to the outer wall of the inner casing (1).

9. The anti-scouring and sedimentation-promoting fixing device for offshore platform pile foundations according to claim 8, characterized in that: The outer casing (4), the protective ring (6) and the bottom plate (7) are all cast with concrete, and steel plates are fixed on the outer surfaces of the outer casing (4), the protective ring (6) and the bottom plate (7), and anti-rust paint is applied to the steel plates; the inner casing (1), the outer casing (4), the protective ring (6) and the bottom plate (7) are all split structures, and the steel plates fixed on the outer surfaces of the outer casing (4), the protective ring (6) and the bottom plate (7) are all provided with wing edges (12) and can be fixed together by the wing edges (12) and bolts.

10. The anti-scouring and sedimentation-promoting fixing device for offshore platform pile foundations according to claim 9, characterized in that: The bottom plate (7) can be placed above the seabed (9) or buried in the seabed (9), and the bottom of the steel plate on the lower end surface of the bottom plate (7) can also be processed with anti-slip serrations.

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