An integrated pile-anchor reinforcement structure and construction method for floating foundations of offshore wind turbines

Abstract

This invention relates to an integrated pile-anchor reinforcement structure and construction method for floating foundations of offshore wind turbines. The structure includes a cylindrical pile-anchor body; at least one flow valve installed at the closed end of the pile-anchor body, the flow valve being mounted on a drainage pump; and an auxiliary reinforcement structure integrated with the pile-anchor body. The auxiliary reinforcement structure includes several reinforcement piles distributed around the pile-anchor body, each pile vertically inserted into the seabed. A constraint frame is simultaneously inserted through the top of each reinforcement pile, and the reinforcement piles are fixed to the constraint frame. The middle position of the constraint frame is fitted onto the pile-anchor body. The reinforcement piles located on the surface of the constraint frame are fixed to the pile-anchor body by locking elements. This invention, through innovative design, optimizes the lateral and vertical resistance of the anchoring system, significantly simplifies the operation and maintenance process, reduces modification and replacement costs, and provides an efficient and reliable solution for the long-term stable operation of deep-sea floating wind turbine foundations.

Description

Technical Field

[0001] This invention relates to an integrated pile-anchor reinforcement structure and construction method for floating foundations of offshore wind turbines, belonging to the technical field of floating foundations for offshore wind turbines. Background Technology

[0002] In recent years, with the continuous increase in global demand for renewable energy, offshore wind power has become one of the important technological approaches to address the energy crisis and reduce carbon emissions. In deep-sea areas, floating wind turbine foundations, with their advantages of flexible adaptation to different water depths and complex geological conditions, have gradually become the mainstream solution for the construction of deep-sea wind farms. As the core anchoring system of floating wind turbine foundations, the pile-anchor structure ensures the structural stability of the wind turbine in extreme weather and long-term operation by providing reliable tensile, shear, and compressive strength. However, the performance of the pile-anchor system directly affects the overall reliability and economy of the floating wind turbine foundation, and its optimized design and reinforcement technology have become one of the key research issues.

[0003] Although pile-anchor systems are widely used in floating wind turbine foundations, they face the following technical challenges in deep-sea applications: 1. Insufficient lateral and vertical load resistance: In the complex environment of deep-sea areas, the anchoring system of floating wind turbine foundations needs to withstand enormous lateral and vertical loads, especially under extreme weather conditions caused by combined wind, waves, and currents. The swaying of the anchor chain can cause disturbance, scouring, and even trenching of the seabed soil around the pile anchor, directly weakening its lateral resistance and threatening the stability of the entire wind turbine foundation. Furthermore, due to the special characteristics of soils in deep-sea areas (such as low-density sand or soft clay layers), the vertical bearing capacity of the pile-anchor system often fails to meet design requirements. 2. Difficulty in pile and anchor installation and maintenance in deep-sea areas: The complex geological conditions and great water depth in deep-sea areas place stringent requirements on the installation and maintenance of anchoring structures. In practical engineering, traditional pile-anchor structures often fail to achieve the ideal penetration depth, or their bearing capacity decreases due to insufficient early penetration. Furthermore, existing retrofitting or reinforcement technologies typically require the complete replacement of the original pile anchors. This method is not only time-consuming and costly, but may also lead to the interruption of floating wind turbine operation, thereby affecting the economic benefits of the wind farm. Third, the dynamic changes in load requirements and insufficient adaptability: With the continuous increase in the single-unit capacity and extended service life of offshore wind turbines, the pile anchor structure needs to cope with dynamically changing load requirements. For example, due to the increase in turbine capacity or adjustments to the operation and maintenance plan, the pile anchor needs 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 requirements, thus limiting the reliability and sustainability of wind farm operation.

[0004] In existing technologies, some solutions improve anchoring performance by optimizing existing pile and anchor designs. For example, the utility model patent "A Tension Leg Floating Wind Turbine" (CN 221820193 U) by Global Marine Engineering (Tianjin) Co., Ltd. proposes a solution for connecting a tension leg floating wind turbine through a foundation laid on the seabed, which is a form of floating wind turbine foundation. However, the seabed foundation designed in this patent does not include scour-resistant design measures. When the area around the foundation is subjected to localized scour, the loss of seabed soil will significantly reduce the foundation's bearing capacity, thereby threatening the safety of the floating wind turbine's superstructure. The invention patent "An Adjustable Mooring Tension Wind Turbine Mooring System" (CN 118850261A) by China Marine Engineering Equipment Technology Development Co., Ltd. proposes an anchor bolt arranged on the seabed for connecting the mooring cable at the bottom of the floating wind turbine platform. However, this patent also does not provide a solution to the problem of reduced bearing capacity of the anchor bolt due to localized scour. Since the safety of the anchor bolt 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 also exist in the invention patents of Shandong Electric Power Engineering Consulting Institute Co., Ltd., entitled "A Self-Stabilizing Floating Wind Turbine Foundation" (CN 118419246 A), and Shanghai East Marine Engineering Technology Co., Ltd., entitled "Mud-Floating Offshore Wind Turbine Foundation and Its Supporting Device and Lifting Device" (CN 117249046 A). While these patents demonstrate different innovations in the design of floating wind turbine foundations, none fully consider the problem of load-bearing capacity failure of seabed anchors due to erosion. In deep-sea wind farms, erosion of seabed soil due to strong currents or waves is a common phenomenon. This phenomenon significantly weakens the supporting performance of anchors, thus 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] This invention provides an integrated pile-anchor reinforcement structure and construction method for floating foundations of offshore wind turbines. Through innovative design, it optimizes the lateral and vertical resistance of the anchoring system, while significantly simplifying the operation and maintenance process, reducing the cost of modification and replacement, and providing an efficient and reliable solution for the long-term stable operation of floating wind turbine foundations in deep-sea areas.

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

[0008] An integrated pile-anchor reinforcement structure for floating foundations of offshore wind turbines includes a pile-anchor body, which is cylindrical in shape. The end of the pile-anchor body that is anchored into the seabed sedimentary layer is defined as the bottom end, and 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 set on the drainage pump;

[0010] It also includes an auxiliary reinforcement structure, which is integrated with the pile anchor body; the auxiliary reinforcement structure includes a number of reinforcement piles, which are distributed around the pile anchor body, and each reinforcement pile is vertically inserted into the seabed; the top of the reinforcement piles is simultaneously fitted with a constraint frame, the reinforcement piles are all fixed to the constraint frame, and the middle position of the constraint frame is fitted onto the pile anchor body.

[0011] The reinforcing piles located on the surface of the constraint frame are fixed to the pile anchor body by locking elements;

[0012] The height of the reinforcing pile is at least twice the height of the main pile anchor.

[0013] Furthermore, eyelets are installed on the circumferential wall of the pile anchor body 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 support rod is fixed near the closed end of the pile anchor body. The support rod has a U-shaped structure. The vertical part of the support rod is symmetrically fixed on the circumferential wall of the closed end of the pile anchor body, and the horizontal part of the support rod is equipped with a hook.

[0015] Furthermore, the constraint frame is trapezoidal in shape, with two reinforcing piles installed on its short side and three reinforcing piles installed on its long side.

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

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

[0018] Step S1: Start the crane and lower the anchor body to the predetermined seabed area using the hook. Use the guide device to ensure that the open end is vertically aligned with the seabed surface.

[0019] Step S2: After the main body of the pile anchor comes into contact with the seabed, it gradually embeds itself into the seabed sedimentary 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 flowing into the pile anchor body is precisely controlled by the flow valve. As the water inside the pile anchor body is gradually emptied, the pressure difference driving effect is enhanced, pushing the pile anchor body to penetrate deep soil until the design depth is reached.

[0021] Step S4: Based on the failure area and load distribution requirements of the pile anchor body, insert several reinforcing piles near the pile anchor body using a guiding device, and use an underwater vibratory hammer, weight stacking, or directional drive module to gradually penetrate the reinforcing piles into the target soil layer.

[0022] Step S5: A mechanical connection is made between the reinforced 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 pile anchor body location and encircle the pile anchor body and several reinforcing columns. The reinforcing columns are fixed to the constraint frame by welding, bolts or mechanical clips.

[0024] Step S7: Extend the restraint frame through the reinforcing plate to cover all the gaps between the reinforcing column and the restraint frame, so that the restraint frame and the pile anchor body are in complete contact.

[0025] Step S8: One end of the fixing chain is installed in the slot of the pile anchor body, and the other end is connected to the offshore wind power floating foundation, completing the construction.

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

[0027] Step S51: Using a remotely operated vehicle or other underwater robot, the locking element is precisely positioned in the gap between the reinforcing pile and the pile anchor body.

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

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

[0030] By employing the above technical solutions, the present invention has the following beneficial effects compared to the prior art:

[0031] 1. The construction method of the integrated pile-anchor reinforcement structure provided by the present invention is a multi-mode installation method, which 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 a modular design and efficient reinforcement methods, which greatly improves its resistance to lateral and vertical loads while ensuring the deep soil embedment effect of the pile-anchor structure.

[0033] 3. The integrated pile-anchor reinforcement structure provided by this invention adopts a highly flexible design, which can effectively adapt and adjust according to changes in wind turbine load and different deep-sea environmental conditions. This allows the system to still provide reliable stability even when the single-unit capacity of the wind turbine increases, operating conditions change, or service life is extended, thereby improving the adaptability and sustainability of floating wind turbine foundations. Attached Figure Description

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

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

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

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

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

[0039] In the diagram: 1 is the main body of the pile anchor, 1A is the open end, 1B is the closed end, 2 is the flow valve, 3 is the drainage pump, 4 is the locking eye, 5 is the chain, 6 is the strut, 7 is the hook, 8 is the reinforcing pile, 9 is the locking element, 10 is the restraint frame, 11 is the mooring line, and 12 is the trench. Detailed Implementation

[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 part," "lower part," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. "First," "second," etc., do not indicate the importance of the components, and therefore should not be construed as a limitation of the present invention. The specific dimensions used in this embodiment are only for illustrating the technical solution and do not limit the scope of protection of the present invention.

[0041] In existing technologies, pile-anchor systems mainly include monopile anchors, suction pile anchors, and towed anchors. Depending on the design and construction methods, the anchoring performance is improved by optimizing existing pile-anchor designs. Taking suction pile anchors as an example, one or more reinforcing rings are installed on their outer wall to increase the contact area between the anchor and the surrounding soil. This design can improve the anchor's resistance to lateral loads in the initial stage. Installing an extension sleeve on the top of the suction pile anchor allows the vertical load to be distributed more evenly to the soil around the pile, thereby improving the vertical bearing capacity. Injecting reinforcing grout around the suction pile anchor increases soil strength and improves the anchor's embedment performance. While these design ideas provide new directions for improving the performance of suction pile anchors, they still have the following problems in practical applications in deep-sea areas: Limited scope of application: The effect of the external reinforcing ring and the top extension sleeve is limited to the surface soil, while the bearing capacity of the deep soil is not significantly utilized, especially under soft clay conditions, where the reinforcement effect is limited. High construction difficulty: The installation and grouting of the reinforcing ring require sophisticated underwater construction techniques, which significantly increases the risks and costs 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 erosion occurs, the bearing capacity of the suction pile anchor will decrease rapidly.

[0042] Therefore, this application provides an integrated pile-anchor reinforcement structure for floating foundations of offshore wind turbines. Figures 1-2 This is a schematic diagram of its overall structure. The main structure is the pile anchor body 1, which adopts a modular cylindrical construction. This design not only facilitates manufacturing, transportation, and installation but also significantly enhances the system's adaptability and functional expansion capabilities. 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 triangular, rectangular, pentagonal, etc.), elliptical, and composite cross-sectional forms. This results in excellent adaptability in soft soil layers, high-density sediments, and complex soil environments. Furthermore, the polygonal and composite cross-sectional designs can further reduce soil disturbance during penetration while optimizing the load distribution path, ensuring high efficiency and stability under lateral and longitudinal loads.

[0043] The design of the anchor body specifically considers the convenience of modular installation. The end of the anchor body that anchors into the seabed sediment layer is defined as the bottom end, and the other end as the top end. The top end is a closed end 1B, and the bottom end is an open end 1A. At least one flow valve 2 is installed at the closed end of the anchor body, and this flow valve is connected to a drainage pump 3, enabling precise control of the fluid inside the anchor body. This control mechanism is one of the core innovations of the system. By precisely adjusting the pressure difference between the internal and external water bodies (pressure differential), it significantly enhances the performance of the anchor body during its penetration into the seabed sediment layer. Specifically, during installation, after the anchor body is slowly lowered to the target seabed position, the drainage pump starts working, gradually extracting water from inside the body. Simultaneously, the flow valve adjusts the inflow rate of external water, thereby creating a significant pressure difference between the inside and outside of the body. This pressure differential-driven mechanism not only firmly embeds the anchor into the seabed sediment but also reduces external soil disturbance, avoiding soil redeposition caused by turbulent water flow, further improving the embedment depth and stability of the device.

[0044] To cope with the extreme conditions of high salinity and high dynamic loads in deep-sea environments, the flow valve is made of high-strength, corrosion-resistant materials and coated with a wear-resistant coating, effectively resisting long-term seawater erosion and mechanical damage. Simultaneously, the internal channels of the flow valve are optimized for fluid dynamics, ensuring minimal turbulence within the channels, thereby reducing energy loss and improving drainage efficiency. These designs significantly extend the service life of the flow valve, enabling it to operate reliably for extended periods in high-pressure, high-salinity environments. Furthermore, the flow valve integrates intelligent regulation functions, capable of real-time monitoring and adjustment of internal fluid parameters, including flow rate, pressure, and temperature. Through connection with high-precision sensors and a central control system, operators can remotely monitor and optimize the flow valve's operating status, achieving intelligent control of the entire pile-anchor penetration 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] Eyelets 4 are installed on the circumferential wall of the anchor body to secure one end of the chain 5, the other end of which connects to the offshore wind turbine floating foundation. The eyelets, the core component connecting the securing chain, are located on one side of the main body. Their design focuses on ensuring the reliability and long-term stability of the chain connection through high-strength materials and optimized geometry. Made of corrosion-resistant alloy material, their surface is strengthened to enhance wear resistance. The optimized connection angle and opening shape effectively disperse the stress applied by the chain, avoiding metal fatigue caused by localized stress concentration. The securing chain is made of high-strength chain, using multi-layer galvanizing and tensile strength optimization technology to ensure high strength and low deformation characteristics in high-salinity, highly dynamic environments. Connecting the offshore wind turbine floating foundation to the anchor system, it efficiently transfers loads in dynamic marine environments. The eyelets and chain, as key functional components of the mechanism, work together to significantly improve the system's adaptability and reliability.

[0046] During the deployment of the integrated pile-anchor reinforcement structure on the seabed, to achieve precise positioning and controlled descent, a support rod 6 is fixed near the closed end of the pile-anchor body. This support rod has a U-shaped structure, with its vertical portion symmetrically fixed to the circumferential wall of the closed end of the pile-anchor body, and a hook 7 installed on its transverse portion. The support rod is made of lightweight, high-strength materials, providing effective balance support during the descent of the pile-anchor and preventing it from tilting or rotating during hoisting or insertion. 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 position along a predetermined trajectory.

[0047] To address the potential decline in load-bearing capacity of pile-anchor reinforced structures during long-term operation, such as insufficient support due to soil erosion, localized scour, or loads exceeding design values, this application designs an auxiliary reinforcement structure. This structure is integrated with the pile-anchor body and, through modular design and an innovative concept of multi-functional collaboration, provides significant lateral and vertical load enhancement capabilities for existing pile-anchor devices. It can also 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 several reinforcement piles 8, which are distributed around the pile anchor body, and each reinforcement pile is vertically inserted into the seabed; the top of the reinforcement piles is simultaneously fitted with a constraint frame 10, and the reinforcement piles are all fixed to the constraint frame, with the middle position of the constraint frame fitted onto the pile anchor body; the reinforcement piles located on the surface of the constraint frame are fixed to the pile anchor body by locking elements 9.

[0049] Reinforced piles are the main support components of integrated reinforced pile systems, significantly enhancing the system's load-bearing capacity through lateral insertion and longitudinal penetration. Their length, diameter, and cross-sectional shape can be flexibly adjusted according to construction conditions and geological environment. In conventional applications, the length of the reinforced pile is typically more than twice the length of the anchor body, ensuring penetration into deep soil areas with high bearing capacity. The cross-sectional shape can be circular, elliptical, or polygonal to optimize penetration resistance and improve load distribution. Reinforced piles are made of high-strength, corrosion-resistant alloy steel or carbon fiber composite materials, combined with fatigue-resistant design, enabling them to maintain stable performance under long-term dynamic load conditions. The installation process utilizes vibratory hammers, gravity stacking, or directional drive modules for efficient penetration, and is complemented by guiding devices to ensure accurate position and angle, thus providing reliable support in complex marine environments. In dynamic marine environments, Figure 4 As shown, the periodic movement of the mooring line 11 may create a trench 12 in front of the main pile anchor, damaging the surrounding soil support structure. In this case, the reinforcing piles, precisely positioned between the trench and the pile anchor body, serve a dual purpose of isolation and soil support restoration. The reinforcing piles not only effectively isolate the main pile anchor from the disturbed area but also rebuild the support strength weakened by soil erosion, thereby preventing the pile anchor body from tilting, shifting laterally, or becoming unstable.

[0050] To adapt to different construction conditions and environmental requirements, the cross-sectional shape and material design of reinforced piles are flexible and diverse. 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 polymers, are preferred for reinforced piles. These materials not only withstand the high salinity and dynamic loads of marine environments but also have high fatigue life, maintaining reliability during long-term operation.

[0051] Locking elements are the core components for enabling the coordinated operation of the pile anchor and the reinforced pile. Their function is to achieve efficient load transfer by eliminating gaps and establishing reliable mechanical coupling. The locking elements are placed in the gap between the pile anchor body and the reinforced pile, eliminating structural loosening through filling or expansion, thereby enhancing the overall system's stability and load-bearing capacity. Locking elements come in various designs, including expandable packers, mechanical locking systems, and cement-filled bags. These elements can be activated by water pressure, heat, or electromagnetic radiation, rapidly expanding and filling the gap, while providing a high-strength mechanical connection after curing. During installation, remotely operated vehicles (ROVs) can assist in the placement and operation of the locking elements, significantly improving the efficiency and safety of deep-sea construction.

[0052] In this innovative design for vertical load dispersion, a constraint frame is used. This frame, by covering the top of the pile anchor body and connecting to the reinforced pile, achieves efficient dispersion of vertical loads. The constraint frame is connected to the top of the reinforced pile via welding or mechanical fixing, while its extended portion covers the closed end of the pile anchor body, forming a stable contact area. This design combines an extended structure and a multi-point connection mechanism, enabling it to distribute some of the load to the surrounding reinforced piles and deep soil when the vertical load borne by the pile anchor exceeds the design value, thereby avoiding localized overload or failure problems caused by load concentration. In actual construction, the constraint frame can also serve as a guiding component, assisting in the penetration and positioning of the reinforced pile, improving the overall accuracy and efficiency of the construction.

[0053] The geometry and connection methods of constraint frames can be customized to meet diverse engineering needs. For example, flat-plate frames are suitable for scenarios with uniform load distribution; they are simple in structure and easy to install and maintain. Reinforced grid frames are used in scenarios with high load requirements; through the multi-point distribution of the grid structure, they significantly improve load dispersion.

[0054] Overall, the extended portion of the restraint frame evenly distributes the vertical load borne by the pile anchor body to multiple reinforced piles, reducing the single-point pressure on the pile anchor body and enhancing the overall system stability. Under the action of waves, ocean currents, or other dynamic loads, the restraint frame, through multi-point contact with the reinforced piles, further disperses the lateral load to the surrounding deep soil, preventing the system from tilting or shifting laterally. Simultaneously, the rigid structure and elastic contact interface of the restraint frame work together to effectively absorb short-term impact loads or periodic load changes, extending the system's service life.

[0055] Preferred, such as Figure 3 As shown, the constraint frame is trapezoidal in shape, with two reinforcing piles installed on its short side and three reinforcing piles installed on its long side.

[0056] Following this, this application further provides a construction method for the aforementioned integrated pile-anchor reinforcement structure, specifically including the following steps:

[0057] Step S1: Start the crane and lower the anchor body to the predetermined seabed area using the hook. Use the guide device to ensure that the open end is vertically aligned with the seabed surface.

[0058] Step S2: After the main body of the pile anchor comes into contact with the seabed, it gradually embeds itself into the seabed sedimentary 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 flowing into the pile anchor body is precisely controlled by the flow valve. As the water inside the pile anchor body is gradually emptied, the pressure difference driving effect is enhanced, pushing the pile anchor body to penetrate deep soil until the design depth is reached.

[0060] Step S4: Based on the failure area and load distribution requirements of the pile anchor body, insert several reinforcing piles near the pile anchor body using a guiding device, and use an underwater vibratory hammer, weight stacking, or directional drive module to gradually penetrate the reinforcing piles into the target soil layer.

[0061] Step S5: A mechanical connection is made between the reinforced 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 pile anchor body location and encircle the pile anchor body and several reinforcing columns. The reinforcing columns are fixed to the constraint frame by welding, bolts or mechanical clips.

[0063] Step S7: Extend the restraint frame through the reinforcing plate to cover all the gaps between the reinforcing column and the restraint frame, so that the restraint frame and the pile anchor body are in complete contact.

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

[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, the locking element is precisely positioned in the gap between the reinforcing pile and the pile anchor body.

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

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

[0069] As described above, the integrated pile-anchor reinforcement structure for offshore wind turbine floating foundations provided in this application has two main advantages: firstly, from a hydrodynamic perspective, it significantly improves the efficiency and stability of the pile-anchor penetration process; secondly, it significantly enhances both lateral and vertical bearing capacity.

[0070] Regarding the aforementioned advantages, this application further provides specific verification results, to Figure 3The given preferred embodiment serves as an example. The two flow valves are configured based on fluid mechanics principles. During pile anchor penetration, the flow valves regulate the internal and external water flow velocities to create a stable pressure gradient. According to Bernoulli's equation, the conversion relationship between fluid kinetic energy and static pressure energy is as follows:

[0071]

[0072] Among them, P 内 and P 外 These are the static pressures inside and outside the pile anchor body, respectively; ρ is the density of seawater; v 内 and v 外 The flow rate is regulated by the multi-channel design of the flow valve. 外 ) lower than the internal drainage velocity (v 内 This creates a static pressure difference ΔP = P between the inside and outside of the pile anchor body. 外 -P 内 The driving pile anchor body is driven into the ground.

[0073] During the penetration test of the soft clay layer, the conditions of a certain marine soft clay (cohesion c = 5 kPa, internal friction angle φ = 10°) were simulated in a laboratory soil tank. A pile anchor system with a flow valve (pressure difference 50 kPa) was used, and the penetration depth reached 12 m, which is 71% higher than the traditional suction pile anchor (without pressure difference drive) of 7 m.

[0074] During the erosion resistance test of the sand layer, the sand conditions were simulated by laboratory soil tank tests (sand density ρ). s =1.8g / cm 3 Permeability coefficient k = 10 -3 The flow valve design reduces the surrounding soil velocity to 0.2 m / s during penetration (compared to 0.8 m / s in the traditional scheme), reducing the soil disturbance area by 60%.

[0075] Regarding the distribution of lateral and vertical loads, the lateral loads are mainly caused by waves, ocean currents, and the dynamic tension of mooring chains. The lateral arrangement of the reinforcing piles forms a composite retaining structure, significantly increasing the passive earth pressure. According to Coulomb's theory, the passive earth pressure P... p for:

[0076]

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

[0078] In the laboratory soil test, a grid arrangement of 2m×3m piles was simulated, with a pile depth of 15m and soil parameters of γ=18kN / m. 3φ=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 scheme is 12cm).

[0079] Under lateral loads, the pile anchor body and the reinforced pile form a rigid connection frame, which is achieved through the moment balance equation in structural mechanics:

[0080]

[0081] Where, k i To strengthen the pile stiffness, δ i The displacement is [not specified]. Laboratory test data shows that multi-point support reduces the maximum bending moment by 50% and controls the lateral displacement to within 5cm, significantly improving the lateral stability of the system.

[0082] The vertical load is transferred to the deep, high-bearing-capacity soil layer 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 reinforcing piles were arranged in a 2m×3m grid, with a pile depth D. f =20m, soil parameters are c=10kPa, γ=18kN / m 3 φ=30°. Test results show that the vertical bearing capacity is 800kN / m. 2 Increased to 1500kN / m 2 This represents 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 by the frame.

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

[0088] The meaning of "and / or" as used in this application includes situations where each exists alone or both exist simultaneously.

[0089] The term "connection" as used in this application can mean a direct connection between components or an indirect connection between components through other components.

[0090] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A construction method for integrated pile-anchor reinforcement structures, characterized in that: It includes the main body of the pile anchor, which is a cylindrical structure. The end of the pile anchor that is anchored into the seabed sedimentary layer is defined as the bottom end, and 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 set on the drainage pump; It also includes an auxiliary reinforcement structure, which is integrated with the pile anchor body; the auxiliary reinforcement structure includes a number of reinforcement piles, which are distributed around the pile anchor body, and each reinforcement pile is vertically inserted into the seabed; the top of the reinforcement piles is simultaneously fitted with a constraint frame, the reinforcement piles are all fixed to the constraint frame, and the middle position of the constraint frame is fitted onto the pile anchor body. The reinforcing piles located on the surface of the constraint frame are fixed to the pile anchor body by locking elements; The height of the reinforcing pile is at least twice the height of the pile anchor body; Specifically, the following steps are included: Step S1: Start the crane and lower the anchor body to the predetermined seabed area using the hook. Use the guide device to ensure that the open end is vertically aligned with the seabed surface. Step S2: After the main body of the pile anchor comes into contact with the seabed, it gradually embeds itself into the seabed sedimentary 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 flowing into the pile anchor body is precisely controlled by the flow valve. As the water inside the pile anchor body is gradually emptied, the pressure difference driving effect is enhanced, pushing the pile anchor body to penetrate deep soil until the design depth is reached. Step S4: Based on the failure area and load distribution requirements of the pile anchor body, insert several reinforcing piles near the pile anchor body using a guiding device, and use an underwater vibratory hammer, weight stacking, or directional drive module to gradually penetrate the reinforcing piles into the target soil layer. Step S5: A mechanical connection is made between the reinforced pile and the pile anchor body through a locking element to form a stable mechanical coupling structure; Step S51: Using a remotely operated vehicle or other underwater robot, the locking element is precisely positioned in the gap between the reinforcing pile and the pile anchor body. Step S52: Depending on the type of locking element, the expansion or filling process is initiated using a water pressure pump, heat conduction equipment, or electromagnetic activation device. Specifically, the expansion packer expands to the gap size using water pressure; the mechanical packer expands to the target position through mechanical operation; and the grouting bag is filled with special grouting material using grouting equipment until it is completely filled. After filling, the curing process is monitored in real time to ensure that there are no gaps or uneven filling problems at the connection points. Step S6: Transport the constraint frame to the pile anchor body position and encircle the pile anchor body and several reinforcing piles. The reinforcing piles are fixed to the constraint frame by welding, bolts or mechanical clips. Step S7: Extend the constraint frame through the reinforcing plate to cover all the gaps between the reinforcing pile and the constraint frame, so that the constraint frame and the pile anchor body are in complete contact. Step S8: One end of the fixing chain is installed in the slot of the pile anchor body, and the other end is connected to the offshore wind turbine floating foundation, thus completing the construction.

2. The construction method according to claim 1, characterized in that: Eyelets are installed on the circumferential wall of the pile anchor body to fix one end of the chain, and the other end of the chain is connected to the floating foundation of the offshore wind turbine. A support rod is fixed near the closed end of the pile anchor body. The support rod has a U-shaped structure. The vertical part of the support rod is symmetrically fixed on the circumferential wall of the closed end of the pile anchor body, and the horizontal part of the support rod is equipped with a hook.

3. The construction method according to claim 1, characterized in that: The constraint frame is trapezoidal in shape, with two reinforcing piles installed on its short side and three reinforcing piles installed on its long side.

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