Integrated pile anchor reinforcing structure for offshore wind turbine floating foundation and construction method

Abstract

The invention relates to an integrated pile anchor reinforcing structure for an offshore wind turbine floating foundation and a construction method, and the integrated pile anchor reinforcing structure comprises a pile anchor main body which is of a cylindrical structure; at least one flow valve is mounted at the closed end of the pile anchor main body, and the flow valve is arranged on a drainage pump; the auxiliary reinforcing structure is integrated with the pile anchor main body; the auxiliary reinforcing structure comprises a plurality of reinforcing piles which are distributed on the periphery of the pile anchor body, and each reinforcing pile is perpendicularly inserted into a seabed. The top ends of the multiple reinforcing piles penetrate through the constraint frame at the same time, the reinforcing piles are all fixed to the constraint frame, and the pile anchor body is sleeved with the middle of the constraint frame. The reinforcing piles located on the surface of the restraining frame and the pile anchor body are fixed through locking elements. Through innovative design, the lateral resistance and the perpendicularity resistance of the anchoring system are optimized, meanwhile, the operation and maintenance process is greatly simplified, the transformation and replacement cost is reduced, and an efficient and reliable solution is provided for long-term stable operation of the deep sea floating type fan foundation.

Description

Technical Field

[0001] The present invention relates to an integrated pile-anchor reinforcement structure for an offshore wind turbine floating foundation and a construction method thereof, belonging to the technical field of offshore wind turbine floating foundations. Background Art

[0002] In recent years, with the increasing global demand for renewable energy, offshore wind power has become one of the important technological solutions for addressing the energy crisis and reducing carbon emissions. In deep-sea areas, floating wind turbine foundations, with their flexibility to adapt to varying water depths and complex geological conditions, have gradually become the mainstream solution for deep-sea wind farm construction. As the core anchoring system of floating wind turbine foundations, pile-anchor structures provide reliable tensile, shear, and compressive resistance, ensuring the structural stability of wind turbines in extreme weather and long-term operation. However, the performance of the pile-anchor system directly affects the overall reliability and economic efficiency of floating wind turbine foundations, and its optimized design and reinforcement technology have become one of the key research issues.

[0003] Although pile-anchor systems have been widely used in floating wind turbine foundations, they face the following technical challenges in deep-sea applications: 1. Insufficient lateral and vertical load resistance of piles and anchors: In the complex environment of the deep sea, the anchoring system of the floating wind turbine foundation needs to withstand huge lateral and vertical loads, especially in extreme weather conditions under the combined effects of wind, waves, and currents. The swinging of the anchor chain will cause disturbance, scouring, and even groove formation of the seabed soil around the pile anchor. This phenomenon directly weakens the lateral resistance of the pile anchor, thereby threatening the stability of the entire wind turbine foundation. In addition, due to the special characteristics of the soil in the deep-sea area (such as low-density sand or soft clay layers), the vertical bearing capacity of the pile-anchor system often fails to meet the design requirements. 2. Difficulty in installing and maintaining piles and anchors in deep-sea areas: The geological conditions in deep-sea areas are complex and the water depth is large, which places strict requirements on the installation and maintenance of the anchoring structure. In actual projects, traditional pile-anchor structures often find it difficult to achieve the ideal penetration depth, or the bearing performance is reduced due to insufficient early penetration. In addition, existing transformation or reinforcement technologies usually require the overall replacement of the original pile anchors. This method not only has a long construction period and high costs, but may also cause interruptions in the operation of floating wind turbines, thereby affecting the economic benefits of the wind farm. 3. Dynamic changes in load requirements and lack of adaptability: With the continuous improvement of the capacity of single offshore wind turbines and the extension of their operating life, pile anchor structures need to cope with dynamically changing load requirements. For example, due to increased wind turbine capacity or adjustments to operation and maintenance plans, pile anchors need to withstand higher vertical and horizontal loads. However, the design flexibility of traditional pile anchor systems is low, making it difficult to meet such dynamically changing needs, thereby limiting the reliability and sustainability of wind farm operations.

[0004] In existing technologies, some solutions improve anchoring performance by optimizing existing pile-anchor designs. For example, Global Marine Engineering (Tianjin) Co., Ltd.'s utility model patent, "A Tension-Leg Floating Wind Turbine" (CN 221820193 U), proposes a solution for connecting a tension-leg floating wind turbine to a foundation located beneath the seabed. This is a form of floating wind turbine foundation. However, the seabed foundation designed in this patent does not include design measures related to scour prevention. When the foundation is subject to local scour, the loss of seabed soil will cause the foundation's bearing capacity to decrease significantly, thereby threatening the safety of the floating wind turbine superstructure. China Marine Engineering Equipment Technology Development Co., Ltd.'s invention patent, "A Wind Turbine Mooring System with Adjustable Mooring Tension" (CN 118850261A), proposes an anchor deployed on the seabed for connecting to a mooring cable at the bottom of a floating wind turbine platform. However, this patent also does not provide a solution to the problem of reduced bearing capacity of the anchor caused by local scour. Because the safety of the anchor is closely related to the integrity of the seabed soil support, scour around the foundation will directly threaten the stability of the mooring system. Similar limitations exist in the invention patents "A Self-Stabilizing Floating Wind Turbine Foundation" (CN 118419246 A) filed by Shandong Electric Power Engineering Consulting Institute Co., Ltd. and "Mud-Floating Offshore Wind Turbine Foundation, Bearing Device, and Lifting Device Thereof" (CN 117249046 A) filed by Shanghai East Marine Engineering Technology Co., Ltd. While these patents incorporate various innovations in the design of floating wind turbine foundations, none fully consider the issue of bearing capacity failure of seabed anchors due to scouring. In deep-sea wind farms, scouring of the seabed soil due to strong currents or wind and wave action is a common phenomenon. This phenomenon significantly weakens the supporting performance of the anchors, posing a potential threat to the safety of floating wind turbine foundations.

[0005] Therefore, it is necessary to propose a new pile-anchor reinforcement structure to solve the above problems. Summary of the Invention

[0006] The present invention provides an integrated pile-anchor reinforcement structure and construction method for offshore wind turbine floating foundations. Through innovative design, the lateral and vertical resistance of the anchoring system are optimized, while the operation and maintenance process is greatly simplified, the cost of modification and replacement is reduced, and an efficient and reliable solution is provided for the long-term stable operation of deep-sea floating wind turbine foundations.

[0007] The technical solution adopted by the present invention to solve its technical problem is:

[0008] An integrated pile-anchor reinforcement structure for an offshore wind turbine floating foundation includes a pile-anchor body having a cylindrical structure, wherein the end of the pile-anchor body anchored in the seabed sediment layer is defined as the bottom end, the other end is defined as the top end, the top end is a closed end, and the bottom end is an open end;

[0009] At least one flow valve is installed at the closed end of the pile anchor body, and the flow valve is arranged on the drainage pump;

[0010] The anchor also includes an auxiliary reinforcement structure integrated with the pile anchor body; the auxiliary reinforcement structure includes a plurality of reinforcement piles, the plurality of reinforcement piles are distributed around the pile anchor body, and each reinforcement pile is vertically inserted into the seabed; a restraining frame is simultaneously passed through the top of the plurality of reinforcement piles, the reinforcement piles are fixed to the restraining frame, and the middle position of the restraining frame is mounted on the pile anchor body;

[0011] The reinforcement piles located on the surface portion of the restraint frame are fixed to the pile anchor body by a locking element;

[0012] The height of the reinforcement pile is at least twice the height of the main pile anchor;

[0013] Furthermore, a clamping eye is installed on the circumferential wall of the pile anchor body, which is used to fix one end of the chain, and the other end of the chain is connected to the offshore wind power floating foundation;

[0014] A strut is fixed near the closed end of the pile anchor body, wherein the strut is of U-shaped structure, the vertical portion of the strut is symmetrically fixed to the circumferential wall of the closed end of the pile anchor body, and a hook is provided on the transverse portion of the strut;

[0015] Furthermore, the constraint frame is in a trapezoidal shape, with two reinforcement piles installed on its short sides and three reinforcement piles installed on its long sides;

[0016] Furthermore, the locking element is an inflatable packer or a mechanical locking system or a cement-filled bag, which expands and fills the gap between the reinforced pile and the pile anchor body after being activated by water pressure, heat or electromagnetic radiation, and forms a mechanical connection after curing;

[0017] A construction method, for the integrated pile-anchor reinforcement structure, specifically comprises the following steps:

[0018] Step S1: Start the crane, lower the pile anchor body to the predetermined seabed area with a hook, and use a guide device to ensure that the open end is vertically aligned with the seabed surface;

[0019] Step S2: After the pile anchor body contacts the seabed, it gradually embeds into the seabed sediment layer by its own weight until it reaches a preliminary stable state;

[0020] Step S3: Start the drainage pump to gradually extract the water inside the pile anchor body. The flow rate of the water outside the pile anchor body is precisely controlled by the flow valve. As the water inside the pile anchor body is gradually emptied, the pressure differential driving effect is enhanced, pushing the pile anchor body to penetrate the deep soil until it reaches the designed depth.

[0021] Step S4: inserting a number of reinforcement piles near the pile anchor body through a guide device according to the failure area of the pile anchor body and the load distribution requirements, and gradually penetrating the reinforcement piles into the target soil layer using an underwater vibratory hammer, a weight stack, or a directional drive module;

[0022] Step S5, mechanically connecting the reinforcement pile and the pile anchor body through a locking element to form a stable mechanical coupling structure;

[0023] Step S6: transport the constraint frame to the location of the pile anchor body, and encircle the pile anchor body and a plurality of reinforcement columns, and fix the reinforcement columns to the constraint frame by welding, bolts or mechanical buckles;

[0024] Step S7, extending the constraint frame through the reinforcement plate to cover all gaps between the reinforcement column and the constraint frame, so that the constraint frame is in full contact with the pile anchor body;

[0025] Step S8: One end of the fixed chain is installed in the eye of the pile anchor body, and the other end is connected to the offshore wind turbine floating foundation, and the construction is completed;

[0026] Furthermore, the construction steps of the locking element include:

[0027] Step S51, using a remotely operated vehicle or other underwater robot, accurately positioning the locking element in the gap between the reinforcement pile and the pile anchor body;

[0028] Step S52: Depending on the type of locking element, an expansion or filling process is initiated using a hydraulic pump, a heat transfer device, or an electromagnetic activation device. In this process, the inflatable packer is inflated to the gap size by hydraulic pressure, the mechanical packer is extended to the target position by mechanical operation, and the grouting bag is filled with a special grouting material by grouting equipment until it is completely filled.

[0029] Step S53: After the filling is completed, the curing process is monitored in real time to ensure that there are no leaks or uneven filling problems at the connection parts.

[0030] Through the above technical solution, compared with the existing technology, the present invention has the following beneficial effects:

[0031] 1. The construction method of the integrated pile-anchor reinforcement structure provided by the present invention is a multi-mode installation method that not only ensures the efficient penetration of the pile-anchor reinforcement structure in complex geological conditions, but also significantly reduces the construction difficulty and cost through flexible combination of construction methods, providing reliable technical support for deep-sea wind farms and other marine engineering facilities.

[0032] 2. The integrated pile-anchor reinforcement structure provided by the present invention adopts modular design and efficient reinforcement means, which not only ensures the deep soil embedment effect of the pile-anchor structure, but also greatly improves its ability to resist lateral and vertical loads;

[0033] 3. The integrated pile-anchor reinforcement structure provided by the present invention adopts a highly flexible design and can effectively adapt and adjust according to changes in wind turbine load and different deep-sea environmental conditions. This allows the system to provide reliable stability even when the wind turbine capacity is increased, operating conditions change, or the operating life is extended, thereby improving the adaptability and sustainability of the floating wind turbine foundation. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention will be further described below with reference to the accompanying drawings and examples.

[0035] Figure 1 This is a three-dimensional view of the integrated pile-anchor reinforcement structure for the offshore wind turbine floating foundation provided by the present invention;

[0036] Figure 2 This is a side view of the integrated pile-anchor reinforcement structure for an offshore wind turbine floating foundation provided by the present invention;

[0037] Figure 3 This is a top view of a preferred embodiment of an integrated pile-anchor reinforcement structure for an offshore wind turbine floating foundation provided by the present invention;

[0038] Figure 4 It is an overall schematic diagram of the implementation of the integrated pile-anchor reinforcement structure for the offshore wind turbine floating foundation provided by the present invention.

[0039] In the figure: 1 is the pile anchor body, 1A is the open end, 1B is the closed end, 2 is the flow valve, 3 is the drainage pump, 4 is the eye, 5 is the chain, 6 is the support rod, 7 is the hook, 8 is the reinforcement pile, 9 is the locking element, 10 is the restraining frame, 11 is the mooring line, and 12 is the groove. DETAILED DESCRIPTION

[0040] The present invention will now be described in further detail with reference to the accompanying drawings. In the description of this application, it should be understood that the terms "left side", "right side", "upper", "lower", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are intended only to facilitate the description of the present invention and simplify the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. "First", "second", etc. do not indicate the importance of the components and therefore should not be understood as limiting the present invention. The specific dimensions used in this embodiment are only for illustrative purposes only and do not limit the scope of protection of the present invention.

[0041] In existing technologies, pile-anchor systems primarily include single pile anchors, suction pile anchors, and drag anchors. Depending on the design and construction method, optimization of existing pile-anchor designs is employed to improve anchoring performance. For example, in suction pile anchors, one or more reinforcement rings are installed on their outer walls to increase the contact area between the pile anchor and the surrounding soil. This design can initially enhance the pile anchor's ability to resist lateral loads. An extension sleeve is installed at the top of the suction pile anchor to more evenly distribute vertical loads to the soil surrounding the pile, thereby improving vertical bearing capacity. Reinforcement grout is injected around the suction pile anchor to increase soil strength and improve the anchor's embedment. While these design approaches offer new avenues for improving suction pile anchor performance, they still present the following challenges in deep-sea applications: Limited range of action: The external reinforcement rings and top extension sleeves act only on the surface soil, while the bearing capacity of the deeper soil layers is not significantly utilized. This enhancement is particularly limited in soft clay soils. High Construction Difficulty: The installation and grouting of the reinforcement ring requires sophisticated underwater construction techniques, which significantly increases the risk and cost of construction in deep water environments. Long-term Performance Degradation: The long-term maintenance of negative pressure suction depends on the stability of the soil structure. Once soil disturbance or scour occurs, the bearing capacity of the suction pile anchor will rapidly decrease.

[0042] Therefore, this application provides an integrated pile-anchor reinforcement structure for offshore wind turbine floating foundations. Figure 1-Figure 2 It is a schematic diagram of its overall structure. The main structure is the pile anchor body 1, which adopts a modular cylindrical structure. This design is not only convenient for manufacturing, transportation and installation, but also significantly enhances the adaptability and functional expansion capabilities of the system. Of course, the cross-sectional shape of the pile anchor body can be customized according to the geological conditions of the target area, including but not limited to circular, polygonal (such as triangle, rectangle, pentagon, etc.), elliptical and composite cross-sectional forms. As a result, it exhibits excellent adaptability in soft soil layers, high-density sediments and complex soil environments. In addition, the design of polygonal and composite cross-sections can further reduce soil disturbance during the penetration process, while optimizing the load distribution path to ensure efficient stability under lateral and longitudinal loads.

[0043] The design of the pile anchor body specifically considers the convenience of modular installation. The end of the pile anchor body anchored into the seabed sediment layer is defined as the bottom end, and the other end is defined as the top end. The top end is the closed end 1B, and the bottom end is the open end 1A. At least one flow valve 2 is installed at the closed end of the pile anchor body. The flow valve is set on the drainage pump 3 to achieve precise control of the fluid inside the pile anchor body. This control mechanism is one of the core innovations of the system. By precisely adjusting the pressure difference (pressure differential) between the internal and external water bodies, it significantly enhances the performance of the pile anchor body during the process of penetrating the seabed sediment layer. Specifically, during the installation process, after the pile anchor body is slowly lowered to the target seabed position, the drainage pump starts working, gradually extracting the water inside the body, and at the same time adjusting the inflow rate of the external water body through the flow valve, thereby forming a significant pressure differential between the inside and outside of the body. This pressure differential drive mechanism not only can firmly embed the pile anchor into the seabed sediment, but also can reduce external soil disturbance, avoid soil re-deposition caused by water flow turbulence, and further improve the embedment depth and stability of the device.

[0044] To withstand the extreme conditions of deep-sea environments, such as high salinity and high dynamic loads, the flow valve is constructed of high-strength, corrosion-resistant materials and coated with a wear-resistant coating, effectively resisting long-term seawater erosion and mechanical damage. Furthermore, the flow valve's internal channel has been optimized for fluid dynamics to minimize water turbulence, thereby reducing energy loss and improving drainage efficiency. These features significantly extend the life of the flow valve, enabling long-term reliable operation in high-pressure, high-salinity environments. Furthermore, the flow valve incorporates intelligent regulation capabilities that monitor and adjust internal fluid parameters, including flow rate, pressure, and temperature, in real time. By connecting to high-precision sensors and a central control system, operators can remotely monitor and optimize the flow valve's operating status, enabling intelligent control of the entire pile anchor installation process. This technology not only improves construction efficiency but also significantly reduces the complexity and risks of manual intervention, providing an efficient and reliable solution for pile anchor installation in deep-sea wind farms.

[0045] An eyelet 4 is installed on the circumferential wall of the pile anchor body, securing one end of a chain 5, the other end of which is connected to the offshore wind turbine floating foundation. The eyelet is the core component that connects the fixed chain and is located on one side of the body. Its design focuses on ensuring the reliability and long-term stability of the chain connection through high-strength materials and optimized geometry. It is manufactured from a corrosion-resistant alloy material, with a surface reinforced to enhance wear resistance. The connection angle and opening shape are optimized to effectively disperse the stress applied by the chain and avoid metal fatigue caused by localized stress concentration. The fixed chain is made of high-strength chain, and through multi-layer galvanizing and tensile strength optimization technology, it ensures high strength and low deformation in high-salinity and highly dynamic environments. It connects the offshore wind turbine floating foundation to the pile anchor system and can efficiently transfer loads in dynamic marine environments. The eyelet and chain are key functional components of the mechanism, and the synergy between these components significantly improves the system's adaptability and reliability.

[0046] During seabed deployment of the integrated pile-anchor reinforcement structure, a support rod 6 is fixed near the closed end of the pile anchor body to ensure precise positioning and controlled descent. This U-shaped support rod has its vertical portion symmetrically fixed to the circumferential wall of the closed end of the pile anchor body, and a hook 7 is attached to its transverse portion. Made of lightweight, high-strength material, the support rod provides effective balancing support during the lowering of the pile anchor, preventing the pile anchor from tilting or rotating during lifting or penetration. The hook, connected to a crane or other lifting machinery, bears the weight of the pile anchor and ensures its smooth descent to the target location along the predetermined trajectory.

[0047] In response to the problem of decreased bearing capacity that may occur in pile-anchor reinforcement structures during long-term operation, such as insufficient support due to soil loss, local scouring or loads exceeding the design value, this application designs an auxiliary reinforcement structure that is integrated with the pile anchor body. Through modular design and combined with the innovative concept of multi-functional collaboration, it provides significant lateral and vertical load enhancement capabilities for existing pile anchor devices, while being able to flexibly adapt to various failure mechanisms, thereby ensuring the long-term stability and reliability of the system under complex conditions.

[0048] The auxiliary reinforcement structure includes a plurality of reinforcement piles 8, which are distributed around the pile anchor body, and each reinforcement pile is vertically inserted into the seabed; a constraint frame 10 is simultaneously passed through the top of the plurality of reinforcement piles, and the reinforcement piles are fixed to the constraint frame, and the middle position of the constraint frame is sleeved on the pile anchor body; the reinforcement piles located on the surface of the constraint frame are fixed to the pile anchor body by a locking element 9.

[0049] Reinforcement piles are the main supporting components of the integrated reinforcement pile mode, which significantly enhance the load-bearing capacity of the system through lateral insertion and longitudinal penetration. Its length, diameter and cross-sectional shape can be flexibly adjusted according to construction conditions and geological environment. In conventional applications, the length of the reinforcement pile is usually more than twice the length of the pile anchor body to ensure that it penetrates into deep soil areas with high bearing capacity. The cross-sectional shape can be circular, elliptical or polygonal to optimize penetration resistance and enhance load dispersion. The material of the reinforcement pile is high-strength, corrosion-resistant alloy steel or carbon fiber composite material, combined with anti-fatigue design, which can maintain stable performance under long-term dynamic load conditions. Its installation process uses a vibratory hammer, gravity stacking or directional drive module to achieve efficient penetration, and cooperates with a guide device to ensure the accuracy of its position and angle, thereby providing reliable support in complex marine environments. In a dynamic marine environment, Figure 4 As shown, the cyclical movement of the mooring line 11 can create a groove 12 in front of the main pile anchor, damaging the surrounding soil support structure. In this situation, reinforcement piles, precisely placed between the groove and the main pile anchor, perform both isolation and soil support restoration. The reinforcement piles not only effectively isolate the main pile anchor from the disturbed area but also restore support strength weakened by soil loss, thereby preventing the main pile anchor from tilting, lateral displacement, or instability.

[0050] To accommodate diverse construction conditions and environmental requirements, reinforcement piles feature a variety of cross-sectional shapes and materials. Common cross-sectional shapes include cylindrical, rectangular, hollow tube, and solid steel columns. High-strength, corrosion-resistant alloy steel or composite materials, such as carbon fiber reinforced polymer, are preferred. These materials not only withstand the high salinity and dynamic loads of marine environments but also exhibit high fatigue life, ensuring reliability over long-term operation.

[0051] The locking element is the core component that enables the pile anchor and the reinforcement pile to work together. Its function is to achieve efficient load transfer by eliminating gaps and establishing reliable mechanical coupling. The locking element is arranged in the gap between the pile anchor body and the reinforcement pile, and eliminates structural looseness problems by filling or expanding, thereby enhancing the stability and load resistance of the overall system. The locking element can be designed in various forms, including inflatable packers, mechanical locking systems, and cement filling bags. These elements can be activated by water pressure, heat or electromagnetic radiation, and quickly expand and fill the gap, while providing a high-strength mechanical connection after curing. During the installation process, remotely operated vehicles (ROVs) can assist in the arrangement and operation of the locking elements, significantly improving the efficiency and safety of deep-sea construction.

[0052] In the innovative design of vertical load dispersion, the present application sets up a constraint frame, which achieves efficient dispersion of vertical loads by covering the top of the pile anchor body and connecting to the reinforcement pile. The constraint frame is connected to the top of the reinforcement pile by welding or mechanical fixing, and its extended part covers the closed end of the pile anchor body to form a stable contact area. This design combines an extended structure and a multi-point connection mechanism. When the vertical load borne by the pile anchor exceeds the design value, it can disperse part of the load to the surrounding reinforcement piles and deep soil, thereby avoiding local overload or failure problems caused by load concentration. In actual construction, the constraint frame can also be used as a guide component to assist in the penetration and positioning of the reinforcement piles, thereby improving the accuracy and efficiency of the overall construction.

[0053] The geometry and connection methods of the restraint frame can be customized to meet diverse engineering needs. For example, a flat-plate frame is suitable for evenly distributed loads, offering a simple structure and easy installation and maintenance. A reinforced grid frame is designed for high-load applications, significantly improving load distribution through the multi-point distribution of the grid structure.

[0054] Overall, the extended portion of the restraint frame evenly distributes the vertical load borne by the pile anchor body to multiple reinforcement piles, reducing single-point pressure on the pile anchor body and enhancing the stability of the overall system. Under the influence of waves, currents, or other dynamic loads, the restraint frame, through multiple points of contact with the reinforcement piles, further disperses the lateral load into the surrounding deep soil, preventing the system from tilting or shifting. Furthermore, the restraint frame's rigid structure, working in tandem with the elastic contact interface, effectively absorbs short-term impact loads or cyclical load variations, extending the system's operational life.

[0055] Preferably, Figure 3 As shown, the constraint frame is in a trapezoidal shape, with two reinforcement piles installed on its short side and three reinforcement piles installed on its long side.

[0056] Next, the present application provides a construction method for the integrated pile-anchor reinforcement structure, which specifically includes the following steps:

[0057] Step S1: Start the crane, lower the pile anchor body to the predetermined seabed area with a hook, and use a guide device to ensure that the open end is vertically aligned with the seabed surface;

[0058] Step S2: After the pile anchor body contacts the seabed, it gradually embeds into the seabed sediment layer by its own weight until it reaches a preliminary stable state;

[0059] Step S3: Start the drainage pump to gradually extract the water inside the pile anchor body. The flow rate of the water outside the pile anchor body is precisely controlled by the flow valve. As the water inside the pile anchor body is gradually emptied, the pressure differential driving effect is enhanced, pushing the pile anchor body to penetrate the deep soil until it reaches the designed depth.

[0060] Step S4: inserting a number of reinforcement piles near the pile anchor body through a guide device according to the failure area of the pile anchor body and the load distribution requirements, and gradually penetrating the reinforcement piles into the target soil layer using an underwater vibratory hammer, a weight stack, or a directional drive module;

[0061] Step S5, mechanically connecting the reinforcement pile and the pile anchor body through a locking element to form a stable mechanical coupling structure;

[0062] Step S6: transport the constraint frame to the location of the pile anchor body, and encircle the pile anchor body and a plurality of reinforcement columns, and fix the reinforcement columns to the constraint frame by welding, bolts or mechanical buckles;

[0063] Step S7, extending the constraint frame through the reinforcement plate to cover all gaps between the reinforcement column and the constraint frame, so that the constraint frame is in full contact with the pile anchor body;

[0064] Step S8: One end of the fixed chain is installed in the eye of the pile anchor body, and the other end is connected to the offshore wind power floating foundation, and the construction is completed.

[0065] In the above construction method, the construction steps of the locking element include:

[0066] Step S51, using a remotely operated vehicle or other underwater robot, accurately positioning the locking element in the gap between the reinforcement pile and the pile anchor body;

[0067] Step S52: Depending on the type of locking element, an expansion or filling process is initiated using a hydraulic pump, a heat transfer device, or an electromagnetic activation device. In this process, the inflatable packer is inflated to the gap size by hydraulic pressure, the mechanical packer is extended to the target position by mechanical operation, and the grouting bag is filled with a special grouting material by grouting equipment until it is completely filled.

[0068] Step S53: After the filling is completed, the curing process is monitored in real time to ensure that there are no leaks or uneven filling problems at the connection parts.

[0069] As described above, the integrated pile-anchor reinforcement structure for offshore wind turbine floating foundations provided by this application offers two specific advantages. First, it significantly improves the efficiency and stability of the pile-anchor penetration process from a fluid dynamics perspective. Second, it significantly enhances both lateral and vertical bearing capacity.

[0070] Regarding the above advantages, this application continues to provide specific verification results to Figure 3The preferred embodiment given is an example. The two flow valves are set based on the principles of fluid mechanics. During the pile anchor penetration process, the flow valves adjust the internal and external water flow velocities to form a stable pressure gradient. According to the Bernoulli equation, the conversion relationship between fluid kinetic energy and static pressure energy is:

[0071]

[0072] Among them, P 内 and P 外 are the static pressure inside and outside the pile anchor body, ρ is the density of seawater, and v 内 and v 外 The external water flow rate (v 外 ) is lower than the internal drainage velocity (v 内 ), thus forming a static pressure difference ΔP=P inside and outside the pile anchor body 外 -P 内 , driving the pile anchor body into penetration.

[0073] During the penetration test of the soft clay layer, the conditions of a certain marine soft clay (cohesion c = 5kPa, internal friction angle φ = 10°) were simulated in a laboratory soil tank. A pile-anchor system with a flow valve (pressure difference 50kPa) was used. The penetration depth reached 12m, which is 71% higher than the 7m of traditional suction pile anchors (no pressure differential drive).

[0074] When continuing to conduct the anti-scour performance test of the sand layer, the sand conditions were simulated by the laboratory soil tank test (sand density ρ s =1.8g / cm 3 , permeability coefficient k = 10 -3 m / s), the flow valve design reduces the flow velocity of the surrounding soil to 0.2m / s during the penetration process (the traditional solution is 0.8m / s), and the soil disturbance area is reduced by 60%.

[0075] In terms of lateral and vertical load distribution, the lateral load is mainly caused by waves, ocean currents and the dynamic tension of the mooring chain. The lateral arrangement of the reinforcement piles forms a composite retaining structure, which significantly increases the passive earth pressure. According to Coulomb theory, the passive earth pressure P p for:

[0076]

[0077] Among them, K p =tan 2 (45°+φ / 2), H is the pile depth.

[0078] In the laboratory soil trench test, the simulated reinforcement pile spacing was 2m×3m grid arrangement, the pile depth was 15m, and the soil parameter was γ=18kN / m 3, φ = 30, cohesion c = 5kPa. The test results show that the lateral bearing capacity is increased by 2.5 times, and the maximum lateral displacement is controlled within 5cm (the traditional solution is 12cm).

[0079] Under the action of lateral load, the pile anchor body and the reinforcement pile form a rigid connection frame, which is based on the moment equilibrium equation in structural mechanics:

[0080]

[0081] Among them, k i is the stiffness of the reinforced pile, δ i Laboratory test data shows that multi-point support reduces the maximum bending moment by 50%, controls the lateral displacement within 5cm, and significantly improves the lateral stability of the system.

[0082] As for vertical loads, they are transferred to deep high-bearing capacity soil layers through the restraint frame and reinforced piles.

[0083] Using Terzaghi's ultimate bearing capacity formula:

[0084] q u =cN c +γD f N q +0.5γBN γ

[0085] In the laboratory soil trench test, the reinforcement piles were arranged in a 2m×3m grid with a pile depth of D f =20m, soil parameters are c=10kPa, γ=18kN / m 3 ,φ=30°. The test results show that the vertical bearing capacity increases from 800kN / m 2 Increased to 1500kN / m 2 , an increase of 87.5%.

[0086] The pile-anchor system under a 10MN vertical load was simulated using finite element analysis software (ANSYS). The results showed that the stress concentration area of the main pile anchor (originally 120MPa) was reduced to 60MPa after being dispersed through the frame.

[0087] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with their meanings in the context of the prior art and, unless defined as such herein, will not be interpreted in an idealized or overly formal sense.

[0088] The meaning of "and / or" in this application means that both situations where each exists alone or both exist at the same time are included.

[0089] The term “connection” as used in this application may mean a direct connection between components or an indirect connection between components via other components.

[0090] With the above-described preferred embodiments of the present invention as a guide, and with reference to the above description, relevant personnel are fully capable of making various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the contents of the specification and must be determined according to the scope of the claims.

Claims

1. An integrated pile-anchor reinforcement structure for an offshore wind turbine floating foundation, characterized by: The pile anchor body is a cylindrical structure, wherein the end of the pile anchor body anchored into the seabed sediment layer is defined as the bottom end, the other end is defined as the top end, the top end is the closed end, and the bottom end is the open end; At least one flow valve is installed at the closed end of the pile anchor body, and the flow valve is arranged on the drainage pump; The anchor also includes an auxiliary reinforcement structure integrated with the pile anchor body; the auxiliary reinforcement structure includes a plurality of reinforcement piles, the plurality of reinforcement piles are distributed around the pile anchor body, and each reinforcement pile is vertically inserted into the seabed; a restraining frame is simultaneously passed through the top of the plurality of reinforcement piles, the reinforcement piles are fixed to the restraining frame, and the middle position of the restraining frame is mounted on the pile anchor body; The reinforcement piles located on the surface portion of the restraint frame are fixed to the pile anchor body by a locking element; The height of the reinforcement pile is at least twice the height of the main pile anchor.

2. The integrated pile-anchor reinforcement structure for an offshore wind turbine floating foundation according to claim 1, characterized in that: A clamping eye is installed on the circumferential wall of the pile anchor body, which is used to fix one end of the chain, and the other end of the chain is connected to the offshore wind power floating foundation; A strut is fixed near the closed end of the pile anchor body. The strut is U-shaped. The vertical portion of the strut is symmetrically fixed on the circumferential wall of the closed end of the pile anchor body, and a hook is provided on the transverse portion of the strut.

3. The integrated pile-anchor reinforcement structure for an offshore wind turbine floating foundation according to claim 1, characterized in that: The restraint frame is in a trapezoidal shape, with two reinforcement piles installed on its short side and three reinforcement piles installed on its long side.

4. The integrated pile-anchor reinforcement structure for an offshore wind turbine floating foundation according to claim 1, characterized in that: The locking element is an inflatable packer or a mechanical locking system or a cement filling bag, which is activated by water pressure, heat or electromagnetic radiation, expands and fills the gap between the reinforced pile and the pile anchor body, and forms a mechanical connection after curing.

5. A construction method for the integrated pile-anchor reinforcement structure according to any one of claims 1 to 4, characterized in that: The specific steps include: Step S1: Start the crane, lower the pile anchor body to the predetermined seabed area with a hook, and use a guide device to ensure that the open end is vertically aligned with the seabed surface; Step S2: After the pile anchor body contacts the seabed, it gradually embeds into the seabed sediment layer by its own weight until it reaches a preliminary stable state; Step S3: Start the drainage pump to gradually extract the water inside the pile anchor body. The flow rate of the water outside the pile anchor body is precisely controlled by the flow valve. As the water inside the pile anchor body is gradually emptied, the pressure differential driving effect is enhanced, pushing the pile anchor body to penetrate the deep soil until it reaches the designed depth. Step S4: inserting a number of reinforcement piles near the pile anchor body through a guide device according to the failure area of the pile anchor body and the load distribution requirements, and gradually penetrating the reinforcement piles into the target soil layer using an underwater vibratory hammer, a weight stack, or a directional drive module; Step S5, mechanically connecting the reinforcement pile and the pile anchor body through a locking element to form a stable mechanical coupling structure; Step S6: transport the constraint frame to the location of the pile anchor body, and encircle the pile anchor body and a plurality of reinforcement columns, and fix the reinforcement columns to the constraint frame by welding, bolts or mechanical buckles; Step S7, extending the constraint frame through the reinforcement plate to cover all gaps between the reinforcement column and the constraint frame, so that the constraint frame is in full contact with the pile anchor body; Step S8: One end of the fixed chain is installed in the eye of the pile anchor body, and the other end is connected to the offshore wind power floating foundation, and the construction is completed.

6. The construction method according to claim 5, characterized in that: The construction steps of the locking element include: Step S51, using a remotely operated vehicle or other underwater robot, accurately positioning the locking element in the gap between the reinforcement pile and the pile anchor body; Step S52: Depending on the type of locking element, a hydraulic pump, a heat transfer device, or an electromagnetic activation device is used to initiate an expansion or filling process. In this process, the inflatable packer is inflated to the gap size by hydraulic pressure, the mechanical packer is mechanically extended to the target position, and the grouting bag is filled with a special grouting material by grouting equipment until it is completely filled. Step S53: After the filling is completed, the curing process is monitored in real time to ensure that there are no leaks or uneven filling problems at the connection parts.

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