A pile foundation scour protection structure combining solidified soil and energy dissipation components

Abstract

This invention relates to a pile foundation scour protection structure combining solidified soil and energy dissipation components, belonging to the field of offshore wind power engineering technology. The pile foundation is a monopile column, with solidified soil filling the area around the bottom of the monopile. Energy dissipation components are arranged around the bottom of the monopile column, which sits on the solidified soil. The energy dissipation components include arc-shaped plates and a frame. The frame is laid along the seabed bottom surface around the monopile foundation. Several arc-shaped plates are fixed to the frame along its laying direction. The arc-shaped plates are arranged in an array. The solidified soil is prepared by mixing flocculant, clay, water-reducing agent, silt, and solidifying agent. This invention's pile foundation scour protection structure combining solidified soil and energy dissipation components is relatively lightweight due to its thin-walled structure, resulting in lower transportation costs and a higher cost-effectiveness ratio. Because it adopts a multi-segment assembly structure, it is easy to disassemble, and parts that fail can be recycled, making it highly environmentally friendly.

Description

Technical Field

[0001] This invention relates to a pile foundation scour protection structure that combines solidified soil with energy dissipation components, belonging to the field of offshore wind power engineering technology. Background Technology

[0002] Wind energy has become a crucial direction for wind power development worldwide, leading to the widespread application of offshore wind turbines in modern marine engineering. The turbine foundation is a vital facility ensuring the safe operation of the turbine. Pile foundations are characterized by their simple structure, mature construction technology, and relatively low construction cost, making them widely used in offshore wind power projects. However, in the marine environment, the foundation structure's influence on ocean hydrodynamics causes localized scour of the turbine's supporting foundation under complex hydrodynamic conditions. This localized scour around the foundation of marine engineering projects significantly increases economic costs; for example, the foundation construction and scour protection costs for offshore wind turbines account for up to 30% of the total economic cost. Therefore, more effective protective measures are needed to curb the scour of the seabed around the pile foundation.

[0003] For research on scour protection of pile foundations, commonly used offshore wind power foundation scour protection measures are generally divided into two categories: active protection by external structures and passive protection such as post-construction rock and sand replenishment, and marine organism attachment protection. Rock and sand replenishment refers to covering the seabed around the pile foundation with a thick layer of rocks and gravel to form a protective layer around the pile. However, the area around the pile foundation is relatively large, requiring a large amount of gravel and crushed stone, resulting in high engineering costs. Furthermore, fixed-point laying and construction in areas with strong currents is difficult, and regular replenishment and maintenance are required in the later stages of the project.

[0004] Existing pile structures often have problems such as large weight, complex installation and difficult hoisting, resulting in uneven stress on the piles during installation, which affects the stability of the wind turbine; poor environmental friendliness, leading to low cost-effectiveness. Summary of the Invention

[0005] This invention employs a pile foundation scour protection method combining solidified soil and energy dissipation components, capable of withstanding complex marine hydrodynamics. The protective structure of this invention is not only lightweight and easy to install, but also effectively reduces the intensity of eddies on the sides and back of the pile, suppressing the formation of horseshoe vortices and thus reducing scour around the pile.

[0006] The present invention adopts the following technical solution:

[0007] The present invention relates to a pile foundation scour protection structure that combines solidified soil and energy dissipation components. The pile foundation is a single pile column, and the bottom of the single pile column is filled with solidified soil. Energy dissipation components are arranged around the bottom of the single pile column located on the solidified soil.

[0008] The energy dissipation component includes an arc-shaped plate and a frame; the frame is laid along the seabed bottom surface around the monopile foundation; there are several arc-shaped plates, which are fixed to the frame along the laying direction of the frame; the several arc-shaped plates are arranged in an array.

[0009] The solidified soil is prepared by mixing flocculant, clay, water-reducing agent, silt and solidifying agent; the silt is waste soil from the construction site, the water is tap water, and the solidifying agent is a soft soil solidifying agent.

[0010] The energy dissipation component laid on the bottom of the pile bed according to the present invention has an arc plate in the form of a semi-circular trough structure. The axial sides of the arc plate of the semi-circular trough structure are open, and the radial ends of the arc plate of the semi-circular trough structure are respectively provided with folded edges extending outward from the trough.

[0011] The energy dissipation component laid at the bottom of the pile bed according to the present invention has a folded edge forming a 1 / 4 circular arc-shaped sheet structure.

[0012] The energy dissipation component laid on the bottom of the pile bed according to the present invention comprises several arc-shaped plates laid on the frame, wherein the arc surfaces of two adjacent arc-shaped plates are arranged opposite each other, and the grooves of two adjacent arc-shaped plates are in opposite directions; the several arc-shaped plates form a trough-shaped energy dissipation structure.

[0013] The energy dissipation component laid on the bottom of the pile bed according to the present invention has a certain gap between two adjacent arc plates;

[0014] An arc-shaped energy dissipation space is formed between the arc-shaped plates with their slots facing downwards and the arc-shaped plates with their slots facing upwards on both sides, along the direction of the arc surface of the arc-shaped plates.

[0015] A certain gap is provided between the folded edges located on both sides of the top crest or bottom trough of the curved plate.

[0016] The energy dissipation component laid on the bottom of the pile bed according to the present invention has a wave-shaped frame, which consists of several parallel frames arranged in parallel with each other; the parallel frames are respectively arranged on the top and bottom of the arc-shaped plate.

[0017] The energy dissipation component laid on the bottom of the pile foundation according to the present invention consists of several arc-shaped plates and several frames forming the energy dissipation component, which is arranged in a grid pattern with the single pile foundation as the center.

[0018] The energy dissipation component laid at the bottom of the pile bed according to the present invention has an arc-shaped plate made of weather-resistant material.

[0019] The solidified soil laid around the pile foundation described in this invention is composed of a solidifying agent made of cement, slag, desulfurized gypsum, silica fume, and fly ash, all uniformly mixed together.

[0020] The energy dissipation component laid at the bottom of the pile bed according to the present invention, as a preferred technical solution of the present invention, has the following characteristics: the ratio of slag to fly ash should be 9:1, the dosage should be 15%, and the water-cement ratio should be 0.7; the optimal liquid-solid ratio of desulfurized gypsum and silica fume synergistic cement curing is between 0.2 and 0.3, and the ratio of desulfurized gypsum:silica fume:cement is 2:1:1. Beneficial effects

[0021] The energy dissipation assembly provided by this invention, laid at the bottom of the pile bed, is relatively lightweight due to its thin-walled structure, resulting in lower transportation costs and a higher cost-effectiveness ratio. Its multi-segment assembly structure facilitates disassembly, and partially damaged sections can be recycled, making it highly environmentally friendly.

[0022] Since this invention does not act directly on the wind turbine, but uses an external arc-shaped structure laid on the seabed, it has a good weakening effect on the formation of horseshoe vortex system around the wind turbine piles, avoiding the expansion of the exposed seabed area, thereby ensuring the integrity and service life of the wind turbine.

[0023] In domestic engineering projects, cement is often used to solidify waste soil. The large-scale use of cement leads to increased carbon emissions and a series of problems such as aggravated environmental pollution. Desulfurized gypsum is a feasible substitute for cement. Furthermore, silica powder, as an admixture, works in conjunction with cement to solidify soil, which can increase the hydration rate of the solidified soil, improve its resistance to ion erosion, and make it superior to traditional solidified soil. Attached Figure Description

[0024] Figure 1 This is a three-dimensional structural schematic diagram (front view) of the energy dissipation structure of the present invention.

[0025] Figure 2 This is a schematic diagram showing the assembly and mesh frame construction of the energy dissipation structure of the present invention before and after its formation.

[0026] Figure 3 This is a three-dimensional structural diagram of the energy dissipation structure of the present invention;

[0027] Figure 4 This is a three-dimensional enlarged view of the arc-shaped plate structure of the present invention;

[0028] Figure 5 This is a schematic diagram of the laying of the solidified soil according to the present invention;

[0029] Figure 6 This is a schematic diagram of the installation of the energy dissipation component of the present invention;

[0030] The diagram includes: 1. Single pile column; 2. Curved plate; 3. Frame; 4. Energy dissipation component; 5. Bed surface; 6. Folded edge; 7. Solidified soil layer. Detailed Implementation

[0031] To make the objectives and technical solutions of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0032] like Figures 1 to 2 As shown, a pile foundation scour protection structure combining solidified soil and energy dissipation components is disclosed. The pile is a single pile foundation 1, and the energy dissipation components include arc-shaped plates 2 and a frame 3. The frame 3 is laid along the seabed bottom surface around the perimeter of the single pile foundation. There are several arc-shaped plates 2, and the frame 3 has a wave-shaped structure with several frames 3 arranged parallel to each other. The parallel frame frames 3 are respectively arranged at the top and bottom of the arc-shaped plates 2. To enhance the lifespan of the device and cope with complex and changeable marine conditions, while reducing environmental pollution, the arc-shaped plates are made of environmentally friendly weather-resistant materials to reduce the corrosive effects of seawater.

[0033] The arc-shaped plate 2 has a semi-circular trough structure, with its axial sides open. To enhance the energy dissipation structure's diversion effect on the transverse water flow, the radial ends of the arc-shaped plate 2 have flanges 6 extending outward from the trough. The flanges 6 have a 1 / 4 arc-shaped sheet structure to maximize the diversion of the transverse water flow.

[0034] Among the several arc-shaped plates 2 laid on the frame 3, the arc surfaces of two adjacent arc-shaped plates 2 are arranged opposite each other, and the slots of two adjacent arc-shaped plates 2 are in opposite directions; the several arc-shaped plates 2 form a trough-shaped energy dissipation structure.

[0035] A certain gap is provided between two adjacent arc-shaped plates 2; an arc-shaped energy dissipation space is formed between the arc-shaped plate 2 with its groove facing downward and the arc-shaped plates 2 with their grooves facing upward on both sides, along the direction of the arc surface of the arc-shaped plate 2; a certain gap is provided between the folded edges 6 located on both sides of the top crest or bottom trough of the arc-shaped plate 2, the size of the gap being about the radius of the folded edge. Small gaps are left between the arc-shaped plates 2 to divert the transverse water flow vertically and longitudinally, thereby reducing its transverse shear force. If it is still necessary to improve the diversion capacity, the sides of the arc-shaped plates can be perforated.

[0036] Several curved plates 2 and several frames 3 constitute an energy dissipation component, which is arranged in a grid pattern around the monopile foundation. The curved plates 2 are made of weather-resistant material.

[0037] The preparation of the solidified soil next to the piles is as follows: Weigh out a certain amount of cement, slag, desulfurized gypsum, silica fume, fly ash, and other raw materials, dry them in advance, and screen the dried materials to remove large-diameter solids. Mix them according to the required ratio, add an appropriate amount of water, pour into a mixing container, and stir evenly to complete the preparation of the solidifying agent. Collect construction waste soil from the nearby construction site, screen impurities through a grate, and put it into a self-made sludge-dissolving tank for sludge-dissolving treatment. Add the solidifying agent and water-based flocculant according to the predetermined ratio and stir continuously to complete the preparation of the solidified soil.

[0038] When a transverse current arrives, the presence of the curved plate causes the incoming flow to impact the plate, creating a splitting effect. The upward flow moves away from the seabed, reducing scouring, while the downward flow flows along the curved plate, reaching the bend zone and forming vortices within its curvature. This vortex disturbs the transverse current, further reducing scouring. The solidified soil uses silt and clay as the base soil, with a certain proportion of cement and a solidifying agent added for solidification. Through physical and chemical reactions between its components and with the clay, the soil's physical and mechanical properties are improved. Compared to ordinary seabeds, its soil compression coefficient is significantly reduced, while its shear strength and compression modulus are significantly increased. It also exhibits better uniformity and effectively enhances the seabed's resistance to scouring.

[0039] The installation method of this invention is as follows:

[0040] The equivalent radius of the piles is calculated based on engineering data, the direction of the main tidal current is obtained, and a laying pattern is drawn in advance. Multiple energy dissipation components are transported to the sea area above the construction site by a sea transport vessel, and the solidifying agent is prepared on board in advance. Silt is dredged nearby to prepare solidified soil, thus forming solidified soil slurry ready for use. The construction point is located directly above the pile foundation to be reinforced, shortening the distance for pumping the solidified soil slurry. The construction pit of the required size and depth is dug in advance near the scour pit, and the solidified soil slurry is pumped into the scour pit underwater of the pile foundation through a delivery pipeline. Then, floats are attached to each set of energy dissipation components to make them float on the water surface, and each set of energy dissipation devices is laid on the sea surface along the pile foundation with the pile as the center.

[0041] When laying the bed around the pile, the total length along the main tidal direction should be more than 5 times the diameter of the offshore wind turbine pile, and the total length along the direction perpendicular to the tidal direction should be more than 3 times the diameter of the offshore wind turbine pile. Too short a laying length is difficult to achieve the effect of preventing scour. For the laying of the bed around multiple piles, the equivalent diameter method can be used to convert the distance between multiple piles into the equivalent single pile diameter for laying.

[0042] To ensure a fixed position, different energy dissipation components can be secured to the frame using methods such as attaching wires. The angles are adjusted until all components form a unified whole and achieve the desired area. The entire assembly is then connected to the transport vessel via temporary ropes, and buoys are continuously released, allowing it to slowly sink to the seabed surface via the ropes, completing the installation.

[0043] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A pile foundation scour protection structure incorporating a solidified soil with an energy dissipating component, characterised in that: The pile foundation is a single pile column (1), the bottom of the single pile column (1) is filled with solidified soil, and the bottom of the single pile column (1) on the solidified soil is provided with an energy dissipation assembly; The energy dissipation assembly comprises an arc-shaped plate (2) and a framework (3); the framework (3) is laid along the seabed surface around the single pile column foundation; the arc-shaped plate (2) is arranged in an array. The arc-shaped plate (2) is in a semicircular groove structure, the axial sides of the arc-shaped plate (2) are open, and the radial ends of the arc-shaped plate (2) are respectively provided with a folded edge (6) extending outward from the groove. The folded edge (6) is in a 1 / 4 circular arc-shaped sheet structure. The arc surfaces of adjacent two arc-shaped plates (2) are oppositely arranged, and the groove openings of the adjacent two arc-shaped plates (2) are oppositely directed. The adjacent two arc-shaped plates (2) are provided with a certain gap. The arc-shaped plates (2) with downwardly arranged groove openings and the arc-shaped plates (2) with upwardly arranged groove openings are arranged in an arc-shaped energy dissipation space along the arc surface of the arc-shaped plate (2). The folded edges (6) located on both sides of the top wave crest or the bottom wave trough of the arc-shaped plate (2) are provided with a certain gap. The solidified soil is prepared by mixing a flocculating agent, clay, a water reducing agent, silt and a solidifying agent.

2. The erosion protection structure of claim 1, wherein, The framework (3) is in a wave shape, and a plurality of frameworks (3) are arranged in parallel.

3. A pile foundation scour protection structure incorporating a solidified soil and energy dissipating component according to claim 1 or 2, characterised in that, The arc-shaped plates (2) and the frameworks (3) form an energy dissipation assembly, and the energy dissipation assembly is arranged in a checkered pattern around the single pile column foundation.

4. The stabilized soil and energy dissipating assembly integrated pile foundation scour protection structure of claim 1, wherein: The arc-shaped plate (2) is made of a weather-resistant material.

5. The stabilized soil and energy dissipating assembly integrated pile foundation scour protection structure of claim 1, wherein: The solidifying agent is uniformly composed of cement, slag, desulfurization gypsum, silica powder, fly ash and xanthan gum.

6. The stabilized soil and energy dissipating assembly integrated pile foundation scour protection structure of claim 5, wherein: The ratio of slag to fly ash in the solidified soil is 9:1, the mixing amount is 15%, the water-cement ratio is 0.7, the liquid-solid ratio of the desulfurization gypsum and the silica powder cooperated with the cement is between 0.2 and 0.3, and the ratio of desulfurization gypsum, silica powder and cement is 2:1:1.

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