An adaptive closed-loop sedimentation type marine pile foundation scour prevention device

Abstract

This invention discloses an adaptive closed-loop sedimentation-type marine pile foundation scour prevention device, comprising a pile sleeve, with multiple radially arranged sand-guiding baffles connected to the outer side of the pile sleeve. The outer end of each sand-guiding baffle is connected to a unidirectional flow-blocking plate. The unidirectional flow-blocking plate consists of a pair of symmetrical side plates, the outer ends of which are hinged to the sand-guiding baffles via a vertical axis. A horizontally placed hydraulic rod connects the sand-guiding baffles and the side plates, with the sand-guiding baffles and / or the side plates hinged to the hydraulic rod. The hydraulic rod extends and retracts with the wave current intensity, driving the side plates to rotate around the vertical axis at an angle α between 15° and 45° with the sand-guiding baffles. When the angle α is 45°, the gap between the side plates of adjacent unidirectional flow-blocking plates is less than 1.5 cm. This effectively solves the technical problems of existing technologies, such as the lack of adaptive sand replenishment and active sand interception mechanisms, and the limited sand accumulation capacity, thus effectively increasing the sand accumulation capacity.

Description

Technical Field

[0001] This invention belongs to the field of marine engineering technology, and in particular relates to an adaptive closed-loop sedimentation type marine pile foundation anti-scour device. Background Technology

[0002] Marine pile foundations are used to support marine structures. By driving or sinking piles into the seabed, they transfer the loads of structures such as offshore platforms, cross-sea bridges, offshore wind power facilities, and marine aquaculture enclosures to the seabed, ensuring the stability and safety of the structures. Because ocean currents scour pile foundations, creating downflows that erode the seabed, scour pits are formed around the piles, leading to pile exposure and decreased stability. Horseshoe vortices, especially those generated in front of the piles, exacerbate localized scour and threaten structural safety. Therefore, existing marine pile foundations incorporate scour protection measures, including active and passive protection. Active protection involves installing scour protection devices around the piles. The main purpose is to weaken the flow field intensity and reduce its sediment-carrying capacity by altering the local flow field characteristics. During installation, part of the scour protection device is buried in the seabed, while the other part lies above the seabed. However, most of these methods are complex, difficult to manufacture, and their protective effect is not ideal. Passive protection is currently the main protective measure adopted in marine engineering. It involves laying protective equipment on the seabed around the pile foundation to improve the erosion resistance of the seabed around the pile foundation. Such methods include riprap, sandbags, solidified soil, and interlocking sluices. However, in actual engineering applications, most of these methods have problems such as inadequate protection and secondary erosion, and local erosion can still occur around the pile foundation.

[0003] Chinese invention patent application CN115538473A discloses a pile foundation protection device and its arrangement method utilizing tidal current characteristics. Specifically, it includes a cylindrical monopile and several arc-shaped columns, with the arc-shaped columns evenly arranged around the cylindrical monopile, the convex side of each column being away from the cylindrical monopile. While the specification states that this can reduce the surrounding flow velocity and turbulence in the complex wave and current environment of the open sea for large-diameter monopile foundations, and induce water to flow out from above with low sediment content, resulting in siltation around the monopile inside the structure, it lacks an adaptive sand replenishment and active sand interception mechanism, limiting the amount of sand accumulation.

[0004] Chinese invention patent application CN113482060A discloses a device and method for preventing scour of pile foundations in marine engineering structures. The device comprises vertical slide rails, horizontal slide rails, a grid plate, and an adjustment mechanism. Multiple vertical slide rails form a circular cylinder, with horizontal slide rails arranged radially around the cylinder. The grid plate, located above the horizontal slide rails, surrounds the circular cylinder in a conical shape to prevent scour.

[0005] The device consists of a conical scour protector with its larger cross-section facing downwards. The cylindrical body connects to a monopile, the lower end of which extends into the seabed. A horizontal slide rail contacts the monopile foundation. The height of the conical scour protector above and below the cylindrical body is adjustable, as is the taper of the conical scour protector. A vertical slide rail is fixed to the monopile, and a vertical sliding seat connected to the horizontal slide rail slides in a sliding engagement with the vertical slide rail. During pile driving, the horizontal slide rail contacts the monopile foundation and adaptively moves towards the upper end of the vertical slide rail. Two sliding seats are installed on the horizontal slide rail, with locking pins passing through locking holes on the horizontal slide rail. When one horizontal sliding seat is locked, it pushes the other horizontal sliding seat to adjust the taper of the conical scour protector to adapt to different ocean currents. It can be seen that the height of the horizontal slide rail and the taper of the conical scour protector are manually adjusted and fixed during installation and do not adaptively adjust during use. Therefore, although its instruction manual states that it "effectively consumes and reduces the kinetic energy of water, weakens or disperses the intensity of horseshoe vortices and tail vortices around a single pile, allows some incoming sand to pass directly through the grid plate, promotes sedimentation and siltation behind the grid plate, reduces toe impact in front of and behind the grid plate, and effectively achieves the anti-scouring effect of slow flow and siltation", sand can also pass through the grid plate, resulting in poor sedimentation effect. Summary of the Invention

[0006] The present invention aims to solve the above-mentioned technical problems existing in the prior art by providing an adaptive closed-loop sedimentation type marine pile foundation anti-scour device.

[0007] The technical solution of this invention is: an adaptive closed-loop sedimentation type marine pile foundation anti-scour device, comprising a pile sleeve, with multiple radially arranged sand guide baffles connected to the outer side of the pile sleeve. The outer end of each sand guide baffle is connected to a one-way flow barrier. The one-way flow barrier is composed of a pair of symmetrical side plates. The outer ends of the side plates are hinged to the sand guide baffles via a vertical axis. A horizontally placed hydraulic rod is connected between the sand guide baffles and the side plates, and the sand guide baffles or / and the side plates are hinged to the hydraulic rod. The hydraulic rod extends and retracts with the wave current intensity, driving the side plates to rotate around the vertical axis. The rotation angle is an angle α between the side plates and the sand guide baffles, which is 15°~45°. When the angle α is 45°, the gap between the side plates of adjacent one-way flow barriers is less than 1.5cm.

[0008] Preferably, a transverse baffle plate located in the vertical middle section of the sand guide plate is fixed to the radial outer side of the pile sleeve, and the transverse baffle plate has multiple vertical through holes.

[0009] Preferably, the sand guide plate has multiple transverse through holes.

[0010] Preferably, the height difference between the upper surface of the sand guide baffle and the upper surface of the one-way flow barrier is 0.2~0.5m.

[0011] Preferably, the outer side of the pile sleeve is evenly distributed with grooves equal in number to the number of sand guide baffles and arranged along the generatrix, and the plug-in fixed to the inner end of the sand guide baffle is inserted into the groove.

[0012] Preferably, the transverse spoiler has radial grooves in the same number as the sand guide baffles, and the sand guide baffles are inserted into the radial grooves and fixed to the transverse spoiler by fasteners.

[0013] The hydraulic rod in this invention can extend and retract with the intensity of the wave flow, driving the side plate to rotate around the vertical axis at an angle α of 15° to 45° with the sand-guiding baffle. When the incoming flow velocity is greater than the upper limit (e.g., 0.5 m / s), the hydraulic rod retracts, and the angle α gradually decreases from 45°. The adjacent one-way flow-blocking plates automatically open, and the resulting radial and arrow-shaped structure has a certain turbulence effect, which can weaken the horseshoe vortex and reduce the scouring capacity of the water flow, thereby weakening the development of scour pits and achieving the purpose of pile foundation scour prevention. At the same time, it can guide the water flow carrying sand and soil into the opening, promoting the accumulation of silt around the pile column. When the incoming flow velocity is less than the lower limit (e.g., 0.3 m / s), the adjacent one-way flow-blocking plates close into an approximately ring-shaped structure with a gap of less than 1.5 cm to prevent suspended silt from spreading with the water flow to the surrounding area, forming a "only-in, no-out" dynamic siltation layer to compensate for the scour area. Experiments show that increasing the sediment thickness can further slow down the water flow velocity inside the cavity. After 10cm of sediment accumulation, the flow velocity within the approximately annular cavity decreases by another 20%. In particular, the transverse flow-dispersing plate with multiple vertical through-holes and the multiple transverse through-holes on the sand-guiding baffle effectively reduce the downflow near the pile, lessen the scouring around the pile foundation, and further facilitate sediment deposition around the pile, thus providing triple protection for the pile through slowing flow, intercepting sediment, and preventing downflow. Simultaneously, the height difference between the surfaces of the sand-guiding baffle and the unidirectional flow-dispersing plate creates a stepped flow gradient, enhancing local turbulence to further promote sediment settling. This invention effectively solves the technical problems of existing technologies, such as the lack of adaptive sediment replenishment and active sediment interception mechanisms, and the limited amount of sand accumulation, effectively increasing the amount of sand accumulation. Furthermore, this invention has a simple structure and is easy to manufacture. In particular, the plug-in structure between the sand-guiding baffle and the pile sleeve is convenient to construct and has low maintenance costs, making it suitable for complex hydrological environments in the deep sea. Attached Figure Description

[0014] Figure 1 This is a structural schematic diagram of an embodiment of the present invention.

[0015] Figure 2 This is a schematic diagram of the structure of the pile sleeve according to an embodiment of the present invention.

[0016] Figure 3 This is a schematic diagram of the structure of the sand guide baffle and the one-way flow barrier in an embodiment of the present invention.

[0017] Figure 4 , Figure 5This is a schematic diagram of the usage state of an embodiment of the present invention. Detailed Implementation

[0018] The present invention discloses an adaptive closed-loop sedimentation-type marine pile foundation scour prevention device, which is made of high-strength corrosion-resistant steel, and its specific structure is as follows: Figure 1 As shown: Similar to the prior art, there is a pile sleeve 1 that can be fitted onto the pile. The difference from the prior art is that the outer side of the pile sleeve 1 is connected to six radially arranged sand guide baffles 2 that are evenly distributed. The length of the sand guide baffles 2 is 1.5D~2.5D (D is the inner diameter of the pile sleeve 1) and the height is 0.3~1.0m. Each sand-guiding baffle 2 has its outer end connected to a one-way flow-blocking plate 3. The one-way flow-blocking plate 3 consists of a pair of symmetrical side plates 31. The outer ends of the side plates 31 are hinged to the sand-guiding baffle 2 via a vertical shaft 4. A horizontally placed hydraulic rod 5 connects the sand-guiding baffle 2 and the side plates 31, and the sand-guiding baffle 2 or / and the side plates 31 are hinged to the hydraulic rod 5 via a hinge support 9. The hydraulic rod 5 extends and retracts with the wave intensity, driving the two side plates 31 to rotate around the vertical shaft 4. The rotation angle is an angle α with the sand-guiding baffle 15° to 45°. When the angle α is 45°, the gap between the side plates 31 of adjacent one-way flow-blocking plates 3 is less than 1.5 cm. A transverse flow-disrupting plate 6 located in the vertical middle section of the sand-guiding baffle 2 is also fixed radially outside the pile sleeve 1. The transverse flow-disrupting plate 6 has multiple vertical through holes 61 distributed on it, and the sand-guiding baffle 2 also has multiple transverse through holes 21. The heights of the sand-guiding baffle 2 and the one-way flow-blocking plate 3 can be equal, but preferably the height difference between their upper surfaces is 0.2~0.5m to form a stepped water flow gradient. A preferred structure is as follows: Figure 2 , Figure 3 As shown, the outer side of the pile sleeve 1 has grooves 7, the same number as the sand guide baffles 2, evenly distributed along the generatrix. The insert 22, fixed to the inner end of the sand guide baffle 2, is inserted into the groove 7. The transverse baffle 6 has radial grooves 62, the same number as the sand guide baffles 2. The sand guide baffles 2 are inserted into the radial grooves 62 and fixed to the transverse baffle 6 by fasteners 8 (angle steel connectors and bolts).

[0019] When the wave velocity exceeds the upper limit (e.g., 0.5 m / s), such as Figure 4 As shown, the hydraulic rod 5 retracts, and the included angle α gradually decreases from 45°. The adjacent one-way flow-blocking plates 3 automatically open, and the resulting radial and arrow-shaped structure has a certain turbulence effect, which can weaken the horseshoe vortex and reduce the scouring capacity of the water flow, thereby weakening the development of scour pits and achieving the purpose of pile foundation scour prevention. At the same time, it can guide the water flow carrying sand and soil to enter through the opening, promoting the accumulation of silt around the pile column; when the wave velocity is less than the lower limit (e.g., 0.3 m / s), such as Figure 5As shown, adjacent one-way baffles close into an approximately ring-shaped structure with a gap of less than 1.5 cm to prevent suspended sediment from spreading to the surrounding area with the water flow, forming a dynamic sedimentation layer that "only enters and does not exit," thus compensating for the scour area.

Claims

1. An adaptive closed-loop sedimentation type marine pile foundation scour prevention device, comprising a pile sleeve (1), characterized in that: The outer side of the pile sleeve (1) is connected to a plurality of radially arranged sand guide baffles (2). The outer end of each sand guide baffle (2) is connected to a one-way flow barrier (3). The one-way flow barrier (3) is composed of a pair of left and right symmetrical side plates (31). The outer end of the side plate (31) is hinged to the sand guide baffle (2) through a vertical shaft (4). A horizontally placed hydraulic rod (5) is connected between the sand guide baffle (2) and the side plate (31). The sand guide baffle (2) and the side plate (31) are hinged to the hydraulic rod (5). The hydraulic rod (5) can extend and retract with the wave intensity, driving the side plate (31) to rotate around the vertical shaft (4). The rotation angle is an angle α of 15° to 45° with the sand guide baffle. When the angle α is 45°, the gap between the side plates (31) of the adjacent one-way flow barrier (3) is less than 1.5cm.

2. The adaptive closed-loop sedimentation type marine pile foundation scour prevention device according to claim 1, characterized in that: The pile sleeve (1) is also fixed with a transverse baffle (6) located in the vertical middle section of the sand guide baffle (2) on the radial outer side. The transverse baffle (6) has multiple vertical through holes (61).

3. The adaptive closed-loop sedimentation type marine pile foundation scour prevention device according to claim 1 or 2, characterized in that: The sand guide plate (2) has multiple transverse through holes (21).

4. The adaptive closed-loop sedimentation type marine pile foundation scour prevention device according to claim 3, characterized in that: The height difference between the upper surface of the sand guide baffle (2) and the one-way flow barrier (3) is 0.2~0.5m.

5. The adaptive closed-loop sedimentation type marine pile foundation scour prevention device according to claim 4, characterized in that: The outer side of the pile sleeve (1) is evenly distributed with grooves (7) equal in number to those of the sand guide baffles (2) and arranged along the generatrix. The plug (22) fixed to the inner end of the sand guide baffles (2) is inserted into the groove (7).

6. The adaptive closed-loop sedimentation type marine pile foundation scour prevention device according to claim 2, characterized in that: The transverse spoiler (6) has radial grooves (62) in the same number as the sand guide baffle (2). The sand guide baffle (2) is inserted into the radial grooves (62) and fixed to the transverse spoiler (6) by fasteners (8).

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