A spud shoe node for preventing scour of a foundation of an offshore platform

Abstract

The utility model relates to offshore platform technical field, concretely is a pile shoe node for preventing foundation scouring of offshore platform, including the fixed connection of novel pile shoe with guide pipe frame main leg, the outer periphery of novel pile shoe is equipped with a plurality of inside thread sleeve, and the sleeve fixed setting is in the outside of novel pile shoe, the detachable connection of sleeve has the spoiler part, and the spoiler part includes screw rod and rotates the rotary fan that sets on screw rod, and the rotary fan rotates relative to screw rod under the action of water flow, the rotary fan includes pivot and a plurality of fan blades that are connected to pivot, first support and second support are fixedly arranged on screw rod, and pivot is connected with screw rod through first support and second support, a plurality of sleeve are distributedly arranged in the outside of novel pile shoe with preset interval, and preset interval is greater than the twice of the rotating radius of rotary fan. The utility model discloses the structure can effectively break the horseshoe vortex around the pile shoe, suppresses local scouring, and is easy to maintain.

Description

Technical Field

[0001] This utility model relates to the field of offshore platform technology, and in particular to a pile shoe node for preventing foundation scour of offshore platforms. Background Technology

[0002] Jacket structure: It is the supporting structure of offshore converter stations and offshore booster stations, consisting of hollow legs and longitudinal and transverse bars connecting the legs;

[0003] Pile shoe: The bottom support structure of the jacket support leg, used to connect the leg to the steel pipe pile and transfer the upper load to the steel pipe pile;

[0004] Erosion: refers to the phenomenon of soil displacement at the seabed where marine engineering structures come into contact with the seabed due to the impact of waves and ocean currents.

[0005] With the continuous expansion of offshore wind power, the long-term stability of the foundation structure of offshore booster stations and offshore converter stations, as key power transmission hubs, is of paramount importance. Currently, pile-type jacket structures are widely used in the foundation design of such platforms. However, under the long-term influence of tides and waves, the soil around the piles is prone to local erosion, leading to pile exposure and reduced bearing capacity, thus threatening the safety of the entire superstructure.

[0006] like Figure 1 The diagram shows an existing pile-shoe type jacket platform, comprising several steel pipe piles 10, a jacket 20, and a surface platform 30. The steel pipe piles 10 are driven into the seabed, the jacket 20 is located in the water, and the surface platform 30 is located above the water surface. The jacket 20 connects the steel pipe piles 10 and the surface platform 30. The connection between the jacket 20 and the steel pipe piles 10 is achieved through existing pile shoes 40. The existing pile shoes 40 are welded to the legs of the jacket 20 in a factory. After welding the existing pile shoes 40, the jacket 20 is placed in the water, and the steel pipe piles 10 penetrate the hollow holes of the existing pile shoes 40 before being driven into the seabed. The portion of the steel pipe pile 10 that is fitted with the existing pile shoes 40 is highly susceptible to erosion.

[0007] Jacket scour refers to the phenomenon where seabed sediment around the foundations of marine structures such as offshore platforms and bridge piers is eroded away by water currents (including tides and waves), causing a local drop in seabed elevation and the formation of scour pits. This is a very important and common problem in marine engineering because it significantly reduces structural stability and, in severe cases, can lead to structural instability or even capsizing. Horseshoe vortices are the primary cause of scour. When water flows against obstacles such as the legs of a jacket, it flows around the structure in front of and to the sides of the upstream face. Directly in front of the structure, the obstructed flow causes increased pressure, forcing some water downwards towards the seabed, and then swirling upwards from the sides of the structure, forming a horseshoe-shaped vortex system.

[0008] Currently, the following methods can be used to prevent seabed erosion:

[0009] Rockfill: Gravel or boulders of a certain grade are dumped around the part where the top of the steel pipe pile 10 connects to the existing pile shoe 40. The weight and porosity of the stones are used to reduce the energy of the water flow and cover the easily eroded soil layer. This method is simple to construct, but it has disadvantages such as easy loss of stones, frequent maintenance, greater impact on the seabed ecological environment and difficulty in precision control.

[0010] Flexible protective mats: These are sand mats made of geotextile-wrapped stones or flexible mats made of interlocking concrete blocks. These mats are laid over a large area on the seabed and can effectively disperse the shear force of water flow and protect the underlying sediment. However, they have limitations such as complex construction technology, high overall cost and poor adaptability to irregular seabed topography.

[0011] Pile foundation shape optimization: Using non-circular cross-sections (such as wing-shaped or polygonal piles) to change the vortex shedding mode. Although this method can reduce scour from the design stage, it is often more expensive to manufacture.

[0012] Therefore, the above-mentioned methods such as riprap filling, flexible protective pads, and pile foundation shape optimization may have limitations such as frequent maintenance, high cost, and poor adaptability. Their anti-scouring effect is unsatisfactory under certain complex sea conditions, which is not conducive to the protection of steel pipe piles 10. Scouring has affected the stable support of the sea surface platform 30. It is urgent to make structural improvements to the existing pile shoe 40 to achieve the anti-scouring effect at the lowest possible cost. Utility Model Content

[0013] The purpose of this invention is to improve the structure of existing pile shoes to prevent erosion of steel pipe piles and ensure the stable operation of offshore platforms.

[0014] To achieve the above objectives, this utility model adopts the following technical solution: a pile shoe node for preventing foundation scour on offshore platforms, comprising a novel pile shoe fixedly connected to the main leg of the jacket; the novel pile shoe has several internally threaded sleeves on its outer periphery, the sleeves being fixedly disposed on the outer side of the novel pile shoe; a flow-disrupting component is detachably connected to the sleeves, the flow-disrupting component including a screw and a rotating fan rotatably disposed on the screw, the rotating fan rotating relative to the screw under the action of water flow; the rotating fan includes the rotating shaft and multiple fan blades connected to the rotating shaft; a first bracket and a second bracket are fixedly disposed on the screw; the rotating shaft is connected to the screw through the first bracket and the second bracket; the several sleeves are distributed at a preset interval on the outer side of the novel pile shoe; the preset interval is greater than twice the rotation radius of the rotating fan.

[0015] Preferably, the top ends of the first bracket and the second bracket are respectively provided with shaft holes, and the two ends of the shaft are rotatably fitted into the corresponding shaft holes. Multiple fan blades are fixedly connected to the shaft, and the outer ends of the multiple fan blades are all connected to the fan blade frame.

[0016] Preferably, the two ends of the rotating shaft are fixedly connected to the top ends of the first bracket and the second bracket, respectively, and multiple fan blades are rotatably sleeved on the rotating shaft, with the outer ends of the multiple fan blades connected to the fan blade frame.

[0017] Preferably, the sleeve is fixed to the outer surface of the novel pile shoe by welding.

[0018] Preferably, the depth to which the turbulence-disrupting component is screwed into the sleeve is adjusted to change its extension length relative to the new type of pile shoe.

[0019] Preferably, the orientation of the fan blades can be adjusted and fixed relative to the direction of water flow.

[0020] Preferably, the new type of pile shoe is fixedly connected to the main leg of the guide frame through a lower conjugate plate, a mid-conjugate plate, and an upper conjugate plate. An upper reinforcing plate is provided between the mid-conjugate plate and the upper conjugate plate, and a lower reinforcing plate is provided between the lower conjugate plate and the mid-conjugate plate.

[0021] Compared with the prior art, the advantages and positive effects of this utility model are as follows:

[0022] 1. Effectively suppresses scour and enhances structural stability: The core of this invention lies in the distributed arrangement of rotatable flow-disrupting components on the outer side of the pile shoe. When the ocean current impacts the pile shoe, the water flow drives a rotating fan to continuously rotate around its axis. This rotational motion actively and continuously disrupts and destabilizes the "horseshoe vortex" structure that is about to form around the pile shoe, fundamentally weakening the main driving force causing localized scour. By improving the flow field around the pile shoe, the vortex's entrainment and scouring effect on seabed sediment is significantly reduced, thereby effectively suppressing the formation and development of scour pits, ensuring the embedment depth and bearing capacity of the steel pipe piles, and improving the long-term stability and safety of the entire offshore platform foundation.

[0023] 2. Ingenious structural design and high flow disturbance efficiency: The distributed layout, with multiple flow disturbance components arranged at a preset interval (greater than twice the rotation radius of the rotating fan) around the outer periphery of the pile shoe, ensures that each flow disturbance component can play its role in its own effective area and that there is no motion interference between them, forming a uniform and efficient three-dimensional flow disturbance barrier.

[0024] 3. Adaptive rotation: The rotating fan can rotate freely under the action of water flow. Its turbulence effect is dynamic and adaptive, and it can respond to water flow of different directions and intensities. Its turbulence efficiency is higher than that of a fixed structure.

[0025] 4. Adjustability and Optimization: The extension length of the turbulence-disrupting component relative to the pile shoe can be adjusted by the depth of screw insertion; simultaneously, the orientation of the fan blades can also be adjusted and fixed according to the mainstream current direction of a specific sea area. This adjustability allows this invention to be optimized for different hydrogeological conditions to achieve the best anti-scour effect.

[0026] 5. Convenient construction, controllable quality, and low cost: Factory prefabrication: Welding of the sleeve to the new type of pile shoe, and connection of the conjugate plate to the pile shoe and the main leg of the jacket, are all completed in the factory. Welding quality is easy to control, ensuring the manufacturing precision and strength of key structural nodes. On-site assembly and installation: The spoiler components are quickly installed through the threaded connection between the screw and the sleeve, eliminating the need for complex offshore welding or large equipment. Construction is simple and fast, greatly reducing the difficulty, time, and risk of offshore operations. Low material cost: The spoiler components have a simple structure, mainly composed of screws, brackets, and fans. The manufacturing process is mature, and the material cost is far lower than traditional measures such as rock dumping or flexible protective pads.

[0027] 6. Modular design for easy maintenance and replacement: The agitator components and pile shoes are connected in a detachable manner, forming a standard modular design. During long-term operation, if a agitator component (such as a fan blade or shaft) is damaged due to corrosion, fatigue, or accidental impact, it can be easily disassembled and replaced underwater without any treatment of the pile shoes or jacket structure. This greatly reduces subsequent maintenance costs and time, and minimizes the platform's downtime due to basic maintenance. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of an existing offshore platform in the background art;

[0029] Figure 2 This is a schematic diagram of the pile shoe structure in this utility model;

[0030] Figure 3 This is a schematic diagram of the structure of the turbulence-causing component involved in this utility model;

[0031] Figure 4 This is a schematic diagram of the structure of the guide frame pile shoe node in this utility model;

[0032] Figure 5 This is a schematic diagram showing the layout of the upper sleeve of the novel guide pile shoe in this utility model;

[0033] Explanation of reference numerals in the attached drawings: 10, steel pipe pile; 20, jacket; 30, offshore platform; 40, existing pile shoe; 1, new pile shoe; 11, lower conjugate plate; 12, conjugate plate; 13, upper conjugate plate; 14, upper reinforcing plate; 15, lower reinforcing plate; 2, sleeve; 3, main leg of jacket; 4, rotating fan; 41, shaft; 42, fan blade; 43, fan blade frame; 5, screw; 51, first support; 52, second support; 53, shaft hole; 6, turbulence-causing component. Detailed Implementation

[0034] As described in the background section... Figure 1 The existing pile shoe 40 is fitted on top of the steel pipe pile 10. Plane a is the sea level, and plane b is the seabed. The portion of the top of the steel pipe pile 10 exposed on plane b is protected by the existing pile shoe 40. However, the existing pile shoe 40 still cannot meet the protection requirements of the steel pipe pile 10 under the "horseshoe" vortex condition. Therefore, in order to prevent scouring of the steel pipe pile 10 and protect the stable operation of the jacket 20 and the offshore platform 30, this utility model proposes the following technical solution:

[0035] A pile shoe node for preventing foundation scour on offshore platforms includes a novel pile shoe 1 fixedly connected to the main leg 3 of the jacket; the novel pile shoe 1 replaces the existing pile shoe 40; the novel pile shoe 1 has several internally threaded sleeves 2 on its outer periphery, the sleeves 2 being fixedly disposed on the outside of the novel pile shoe 1, and the sleeves 2 are selected to be fixed to the outside of the novel pile shoe 1 by welding at the factory; a flow-disrupting component 6 is detachably connected to the sleeve 2, the detachable connection being a threaded connection; the flow-disrupting component 6 is adjusted by the depth to which it is screwed into the sleeve 2 via a screw 5, thereby adjusting its extension length relative to the novel pile shoe 1. The flow-disrupting component 6 includes a screw 5 and a rotating fan 4 rotatably mounted on the screw 5. The rotating fan 4 rotates relative to the screw 5 under the action of water flow. The rotating fan 4 includes a rotating shaft 41 and multiple fan blades 42 connected to the rotating shaft 41. A first bracket 51 and a second bracket 52 are fixedly mounted on the screw 5. The rotating shaft 41 is connected to the screw 5 through the first bracket 51 and the second bracket 52. The plurality of sleeves 2 are distributed at a preset spacing H on the outside of the new type of pile shoe 1. The preset spacing H is generally 0.5 to 2 m. The preset spacing H is greater than twice the rotation radius R of the rotating fan 4. The vertical and horizontal spacing between the sleeves 2 are both greater than 2R, so that the rotating fans 4 will not interfere with each other when rotating. The orientation of the fan blades 42 of the rotating fan 4 can be adjusted and fixed relative to the direction of water flow.

[0036] The rotation of the rotating fan 4 relative to the screw 5 under the action of water flow can be achieved in the following way: The top ends of the first support 51 and the second support 52 are respectively provided with shaft holes 53. The two ends of the rotating shaft 41 are rotatably fitted into the corresponding shaft holes 53. Multiple fan blades 42 are welded to the middle of the rotating shaft 41, and fan blade frames 43 are welded to the outer ends of each fan blade 42. The radius of the fan blade frame 43 is R. The fan blade frame 43 sweeps across the space formed between the first support 51 and the second support 52 as the fan blades 42 rotate. The fan blade frame 43 is used to maintain the overall structural strength of the fan blades 42 and to form a more continuous and stable turbulence surface during rotation. When water flow attempts to scour the steel pipe pile 10, since the rotating fan 4 is located on the outer periphery of the new type pile shoe 1, the rotating fan 4 will rotate due to the action of the water flow. During the rotation of the rotating fan 4, the water flow vortex is dispersed. Even if a small portion of the water flow passes through the rotating fan 4, it will first impact the new type pile shoe 1 and will not have too much impact on the steel pipe pile 10.

[0037] The rotation of the rotating fan 4 relative to the screw 5 under the action of water flow can also be achieved in the following way: multiple fan blades 42 are rotatably connected to the rotating shaft 41, and fan blade frames 43 are welded to the outer ends of the multiple fan blades 42. The two ends of the rotating shaft 41 are welded and fixedly connected to the top ends of the first support 51 and the second support 52, respectively. The radius of the fan blade frame 43 is R, and the fan blade frame 43 sweeps across the space formed between the first support 51 and the second support 52 as the fan blades 42 rotate. When water flow wants to scour the steel pipe pile 10, since the rotating fan 4 is located on the outer periphery of the new type of pile shoe 1, the rotating fan 4 will rotate around the rotating shaft 41 due to the action of water flow. In this design, the rotating shaft 41 does not rotate, and the fan blade frame 43 rotates synchronously with the fan blades 42, which disperses the water flow vortex during the rotation.

[0038] The new type of pile shoe 1 is fixedly connected to the main leg 3 of the jacket foundation by welding a lower conjugate plate 11, a mid-conjugate plate 12, and an upper conjugate plate 13. The distance between the mid-conjugate plate 12 and the upper conjugate plate 13, and the distance between the lower conjugate plate 11 and the mid-conjugate plate 12, are both h, which is generally 4-5m. An upper reinforcing plate 14 is provided between the mid-conjugate plate 12 and the upper conjugate plate 13; a lower reinforcing plate 15 is provided between the lower conjugate plate 11 and the mid-conjugate plate 12. During construction, the sleeve 2 is welded to the outer periphery of the new type of pile shoe 1 in the factory. Then, the new type of pile shoe 1 is welded to the main leg 3 of the jacket foundation by welding the lower conjugate plate 11, the mid-conjugate plate 12, and the upper conjugate plate 13. Then, the flow-disrupting component 6, which is detachably connected to the sleeve 2, is installed. After the main leg 3 of the jacket foundation, carrying the new type of pile shoe 1, is placed on plane b, the steel pipe pile 10 is then inserted through the new type of pile shoe 1 and driven into the seabed.

[0039] In an example, under normal marine conditions, it is recommended to arrange 7 rows of 8 plates each, excluding the outer side near the main leg 3 of the jacket structure, because of the presence of the lower conjugate plate 11, the middle conjugate plate 12, and the upper conjugate plate 13. The arrangement direction is shown in [reference needed]. Figure 5 The sleeves 2 can be arranged in a quincunx pattern or aligned. During arrangement, the spacing between the sleeves 2 must meet the space requirements for the installation and rotation of the flow-disrupting component 6. Under different water depths and soil conditions, the arrangement of the sleeves 2, the number of sleeves 2, the extension length of the flow-disrupting component 6 relative to the new pile shoe 1, and the orientation of the fan blades 42 of the flow-disrupting component 6 can be optimized and adjusted based on numerical simulation and flue test results to ensure the best anti-scouring effect. According to the specifications, the connection length between the screw 5 and the sleeve 2 should be 500mm. Since this small node is not a critical structural component, it is recommended to appropriately relax the requirement to about 300mm to allow for adjustment of the orientation of the fan blades 42. Figure 3 , Figure 4 The scour-preventing pile shoe node shown includes a new type of pile shoe 1, an internally threaded sleeve 2, and a flow-disrupting component 6. The sleeve 2 is connected to the new type of pile shoe 1 by welding. The sleeve 2 is connected to the new type of pile shoe 1 at the component factory. The sleeve 2 can be flexibly arranged, and the spacing between the sleeves 2 must meet the space requirements for the installation and rotation of the flow-disrupting component 6. The flow-disrupting component 6 includes a screw 5 and a rotating fan 4. The rotating fan 4 can rotate around its own shaft 41 in the direction of the water flow. The rotating fan 4 includes a shaft 41 and multiple fan blades 42 welded to the middle of the shaft 41. The outer ends of the multiple fan blades 42 are located inside the fan blade frame 43 and welded to the inner wall of the fan blade frame 43. The rotating fan 4 is rotatably connected to the screw 5 through the shaft 41. A first bracket 51 and a second bracket 52 are welded on the screw 5. The top of the first bracket 51 and the second bracket 52 are respectively provided with shaft holes 53 that can be inserted into both ends of the shaft 41. When connecting the flow-disrupting component 6, the extension length and the direction of the flow-disrupting component 6 can be adjusted as needed. The turbulence-disrupting component 6 consists of a screw 5 and a rotating fan 4. The screw 5 is used to connect with the sleeve 2, and the rotating fan 4 can rotate in the direction of the water flow to disrupt the surrounding eddies.

[0040] When ocean currents act on the main leg 3 of the jacket foundation and its surrounding components, a typical horseshoe vortex forms at the bottom of the structure. This vortex structure is the main cause of localized scour. This invention proposes to install a rotatable rotating fan 4 component at the new pile shoe 1. By actively disturbing the flow field, the formation and development of the horseshoe vortex are weakened, thereby effectively reducing the risk of localized scour around the main leg 3 of the jacket foundation and extending the service life of the foundation. For different sea area hydrodynamic conditions, this invention can flexibly adjust the arrangement of the sleeve 2, the extension length of the disturbance component 6, and the orientation of the fan blade 42 according to the actual working conditions to achieve optimal control of the flow field disturbance effect. The rotating fan 4 component designed in this invention can rotate under the action of water flow, similar to the working principle of a windmill. When the rotating fan 4 rotates with the water flow, it continuously changes the velocity distribution and streamline morphology of the local flow field, thereby significantly weakening the intensity and scale of the horseshoe vortex around the new pile shoe 1 and effectively suppressing the development of localized scour. In terms of construction technology, the sleeve 2 and the disturbance component 6 are connected by standardized bolts. This method not only simplifies the installation process and improves construction efficiency, but also facilitates the control of construction quality. At the same time, this connection method has good maintainability. When the fan blade 42 or the turbulence component 6 is damaged due to long-term service or extreme operating conditions, individual components can be quickly disassembled and replaced, thereby reducing maintenance costs and shortening downtime.

Claims

1. A pile shoe joint for preventing foundation scour in offshore platforms, characterized in that: The system includes a new type of pile shoe (1) fixedly connected to the main leg (3) of the guide frame; the new type of pile shoe (1) has several internally threaded sleeves (2) on its outer periphery, and the sleeves (2) are fixedly set on the outside of the new type of pile shoe (1); a flow-disrupting component (6) is detachably connected to the sleeves (2), the flow-disrupting component (6) includes a screw (5) and a rotating fan (4) rotatably set on the screw (5), the rotating fan (4) rotates relative to the screw (5); the rotating fan (4) includes a rotating shaft (41) and a plurality of fan blades (42) connected to the rotating shaft (41); a first bracket (51) and a second bracket (52) are fixedly set on the screw (5); the rotating shaft (41) is connected to the screw (5) through the first bracket (51) and the second bracket (52); the plurality of sleeves (2) are distributed on the outside of the new type of pile shoe (1) at a preset interval; the preset interval is greater than twice the rotation radius of the rotating fan (4).

2. The pile shoe joint for preventing foundation scour of offshore platforms according to claim 1, characterized in that: The top ends of the first bracket (51) and the second bracket (52) are respectively provided with shaft holes (53). The two ends of the shaft (41) are respectively rotatably fitted into the corresponding shaft holes (53). Multiple fan blades (42) are fixedly connected on the shaft (41), and the outer ends of the multiple fan blades (42) are all connected to the fan blade frame (43).

3. The pile shoe joint for preventing foundation scour of offshore platforms according to claim 1, characterized in that: The two ends of the rotating shaft (41) are fixedly connected to the top of the first bracket (51) and the second bracket (52) respectively. Multiple fan blades (42) are rotatably mounted on the rotating shaft (41), and the outer ends of the multiple fan blades (42) are all connected to the fan blade frame (43).

4. The pile shoe node for preventing foundation scour of offshore platforms according to claim 1, characterized in that: The sleeve (2) is fixed to the outer surface of the new type of pile shoe (1) by welding.

5. The pile shoe joint for preventing foundation scour of offshore platforms according to claim 1, characterized in that: The turbulence component (6) is screwed into the sleeve (2) by the screw (5) to adjust its extension length relative to the new pile shoe (1).

6. The pile shoe joint for preventing foundation scour of offshore platforms according to claim 2 or 3, characterized in that: The orientation of the blades (42) of the rotating fan (4) can be adjusted and fixed relative to the direction of water flow.

7. The pile shoe node for preventing foundation scour of offshore platforms according to claim 1, characterized in that: The new type of pile shoe (1) is fixedly connected to the main leg (3) of the guide frame through the lower conjugate plate (11), the middle conjugate plate (12), and the upper conjugate plate (13). An upper reinforcing plate (14) is provided between the middle conjugate plate (12) and the upper conjugate plate (13); a lower reinforcing plate (15) is provided between the lower conjugate plate (11) and the middle conjugate plate (12).

Images