A telescopic suction anchor and method of installation and recovery thereof

Abstract

This invention belongs to the field of marine engineering fundamentals and mooring technology, and discloses a telescopic suction anchor and its installation and retrieval method. It includes an outer cylinder and an inner cylinder, as well as a fixing and sealing device, a negative pressure device, and a mooring device. The inner cylinder is nested inside the outer cylinder and can telescopically extend relative to the outer cylinder along the axial direction. The fixing and sealing device is located between the inner and outer cylinders to achieve a fixed connection, relative movement switching, and sealing isolation between the inner and outer cylinders. The negative pressure device is connected to the sealed space inside the anchor body, providing pressure power for the insertion and retrieval of the suction anchor. The mooring device is located on the anchor body. This invention, by setting up telescopic inner and outer anchor bodies and a staged insertion mechanism, achieves functional decoupling between the installation and service stages. While ensuring installation feasibility, it improves the overall load-bearing capacity of the suction anchor, effectively solves the application bottlenecks of traditional suction anchors, meets the anchoring needs of different marine engineering projects, and improves the economy and safety of anchoring projects.

Description

Technical Field

[0001] This invention belongs to the field of marine engineering fundamentals and mooring technology, specifically relating to a telescopic suction anchor and its installation and retrieval method, applicable to mooring and anchoring of marine engineering facilities such as offshore wind power generation equipment and floating production storage and offloading (FPSO) units. Background Technology

[0002] Suction anchors (also known as suction tubes or suction caissons) are commonly used seabed anchoring foundations in the field of marine engineering. With their advantages of convenient installation, strong adaptability, and recyclability, they are widely used in various marine geological areas such as soft clay, silt, and fine sand. They are the core anchoring form for offshore platforms, floating structures, offshore wind power and other facilities. Their load-bearing capacity directly determines the operational safety and service life of marine engineering facilities.

[0003] On the one hand, during the penetration of a suction anchor, the anchor body needs to overcome the penetration resistance generated by the seabed soil. This penetration resistance mainly includes the side friction resistance of the outer wall of the anchor body, the side friction resistance of the inner wall, and the end resistance. As the size of the suction anchor increases or the penetration depth increases, the resistance of each part gradually increases synchronously during penetration, resulting in a significant increase in the negative pressure required during the installation phase. Especially in large deep-water suction anchors, excessive installation negative pressure can easily lead to problems such as anchor body instability, increased seabed disturbance, penetration difficulties, and even installation failure. On the other hand, to improve the pull-out bearing capacity and combined load bearing performance of suction anchors in complex marine environments, existing technologies typically enhance their bearing capacity by increasing the anchor body size, adding auxiliary load-bearing structures, or setting up composite load-bearing systems. However, while these improvements increase the bearing capacity during service, they also simultaneously increase the penetration resistance that needs to be overcome during installation. In other words, existing suction anchors generally suffer from a problem of "increased bearing capacity" coupled with "increased installation difficulty."

[0004] To improve the pull-out bearing capacity of suction anchors, some improved products in the existing technology have added internal and external baffles, fins, or adopted multi-barrel and pile-anchor hybrid structures. Related technologies can be found in "Attached Barbed Reinforced Suction Anchor (Patent No. CN202411630515.X)," "Piston-Type Suction Anchor and Its Installation and Recovery Method (Patent No. CN202411614828.6)," "A Ring Anchor and Torsional Bearing Capacity Calculation Method and Its Installation and Recovery Components (Patent No. CN202310387597.9)," and "Suction Pile Anchor System and Marine Aquaculture Platform (Patent No. CN202411367730.5)." However, most of the above structures adopt a fixed, integral penetration method, with each reinforcing structure participating in the stress simultaneously during installation, further increasing the total resistance during penetration. Especially for multi-cylinder or composite structures, the negative pressure requirements and construction control during installation are significantly increased due to the simultaneous interaction of multiple stress-bearing parts with the seabed soil. Therefore, it is difficult to meet the dual requirements of installation feasibility and high load-bearing capacity, resulting in obvious limitations under complex working conditions.

[0005] As offshore wind power continues to expand into deeper waters, marine engineering places higher demands on the load-bearing capacity and environmental adaptability of suction anchors, highlighting the increasing limitations of single-anchor foundations. Existing suction anchors cannot flexibly adjust their structural parameters based on seabed soil mechanics, water depth, environmental loads, and other environmental conditions. They also fail to fully consider the synergistic effect of the inner and outer anchor bodies, making it difficult to achieve a balance between installation feasibility and load-bearing performance. Furthermore, in existing suction anchor structures, the same fixed load-bearing structure is typically used during both the installation and service phases. This means that structural dimensions or auxiliary structures used to enhance load-bearing capacity during service also directly participate in the penetration stress process during installation. Therefore, there is a lack of a structural mechanism for functional separation and dynamic adjustment to meet the stress requirements of different phases.

[0006] The shortcomings of the existing technologies necessitate the development of a telescopic suction anchor and its installation and retrieval method. Summary of the Invention

[0007] To meet the engineering needs of marine engineering projects expanding into deeper waters and to address the technical challenges of the difficulty in installing traditional suction anchors and their insufficient load-bearing capacity, this invention proposes a telescopic suction anchor and its installation and retrieval method that enables phased insertion, reduces installation difficulty, and improves overall load-bearing performance. By setting up telescopic inner and outer anchor bodies and a phased insertion mechanism, the functions of the installation and service phases are decoupled. This ensures installation feasibility while improving the overall load-bearing performance of the suction anchor, effectively solving the application bottleneck of traditional fixed-size suction anchors, meeting the anchoring needs of different marine engineering projects, and improving the economy and safety of anchoring projects.

[0008] The technical solution is as follows: This invention proposes a telescopic suction anchor, comprising an anchor body, which includes an outer cylinder and an inner cylinder. The telescopic suction anchor also includes a fixing and sealing device, a negative pressure device, and a mooring device. The inner cylinder is nested inside the outer cylinder and can telescopically extend relative to the outer cylinder along the axial direction. The fixing and sealing device is disposed between the inner and outer cylinders to achieve a fixed connection, relative movement switching, and sealing isolation between the inner and outer cylinders. The negative pressure device communicates with the sealed space inside the anchor body, providing pressure power for the insertion and retrieval of the suction anchor. The mooring device is disposed on the anchor body for connection to a marine engineering mooring system.

[0009] Furthermore, the fixing and sealing device has two working states. In the first state, it locks the relative movement of the inner cylinder and the outer cylinder and keeps them sealed. In the second state, it releases the restriction on the relative movement of the inner cylinder and the outer cylinder while continuously maintaining the seal between the inner and outer cylinders.

[0010] Furthermore, the outer and inner cylinders are installed using a staged penetration method. The outer cylinder penetrates the seabed soil first, and then the inner cylinder continues to penetrate downwards, so as to achieve the staged release of penetration resistance.

[0011] Furthermore, the fixed sealing device includes a sealing seat, a sealing ring, a locking mechanism, and a control component; the sealing seat is located at the through hole at the top of the outer cylinder and is welded to the outer cylinder for sealing; the sealing ring is located inside the sealing seat to achieve a sealed connection between the sealing seat and the inner cylinder; the locking mechanism is fixedly connected inside the sealing seat, and the locking mechanism achieves locking and unlocking of the inner cylinder through the control component.

[0012] Furthermore, the locking mechanism is set as an electromagnet; the inner cylinder is made of ferromagnetic material.

[0013] Furthermore, the inner and outer cylinders work together to transfer loads during service, thereby improving the overall load-bearing capacity of the suction anchor and its structural stability under complex load conditions.

[0014] Furthermore, the negative pressure device includes a water pump, a negative pressure suction and discharge pipeline, a reversing shut-off valve, and a pressure sensor; one end of the negative pressure suction and discharge pipeline is sealed to the through hole at the top of the inner cylinder, and the other end is connected to the water pump and the pressure sensor; a reversing shut-off valve is installed on the negative pressure suction and discharge pipeline, which enables bidirectional functions of water suction and water injection recovery through valve switching; the pressure sensor monitors the pressure inside the anchor body cavity in real time, matches the pressure requirements of the penetration and recovery conditions, and automatically adjusts the negative pressure value through the control system to ensure a smooth penetration process.

[0015] This invention also proposes a method for installing and retrieving a telescopic suction anchor, applicable to the aforementioned telescopic suction anchor, comprising the following steps: Step 1: Penetration by overall self-weight: Under the action of the anchor body's own weight, the suction anchor initially penetrates into the seabed soil; Step 2, suction penetration of the outer cylinder: After the bottom of the telescopic suction anchor forms a closed space with the seabed soil, the negative pressure device is activated. Under the action of negative pressure, the outer cylinder and the inner cylinder are synchronously penetrated into the seabed soil. Step 3, suction penetration of the inner cylinder: After the outer cylinder reaches the predetermined penetration depth, release the restriction of the vertical movement of the inner cylinder by the fixing sealing device, while maintaining the sealing state between the inner and outer cylinders; continue to start the negative pressure device, so that the inner cylinder continues to penetrate into the seabed soil under the action of negative pressure until the set penetration depth is reached.

[0016] Step 4, Mooring of the suction anchor: After the telescopic suction anchor is installed, the suction anchor is connected to the mooring structure through the mooring device to anchor offshore wind power, floating platforms and other marine engineering facilities. Step 5, Recovery of the suction anchor: When the suction anchor reaches the end of its service life or needs to be repositioned, water is injected into the anchor body through a negative pressure device to change the pressure difference between the inside and outside of the anchor body. Under the action of water pressure, the inner and outer cylinders gradually detach from the seabed soil, thereby realizing the overall recovery of the suction anchor.

[0017] Furthermore, in steps 1 and 2, the fixed sealing device locks the relative movement between the inner and outer cylinders and maintains the sealing performance between the inner and outer cylinders.

[0018] Furthermore, steps 2 and 3 utilize a phased penetration method of "penetrating the outer cylinder first and then the inner cylinder" to achieve phased release of penetration resistance during the installation phase.

[0019] Compared with the prior art, the advantages of the present invention are as follows: 1. Achieving a balance between installation feasibility and load-bearing capacity: This invention achieves functional decoupling between the installation and service phases through a phased penetration mechanism of the inner and outer cylinders, improving the coupling relationship in traditional suction anchors where "increased load-bearing capacity leads to a simultaneous increase in installation resistance." By releasing penetration resistance in stages, the peak negative pressure requirement during installation can be effectively reduced, improving the installation feasibility of large suction anchors in deep-water environments.

[0020] 2. Improved Overall Bearing Capacity of Suction Anchors: This invention expands the contact area between the anchor body and the soil through the synergistic effect of the inner and outer cylinders, enhancing the restraint effect of the surrounding soil and increasing the lateral friction and end bearing capacity of the suction anchor. This, in turn, improves the overall stability of the suction anchor under horizontal, vertical, and combined load conditions. Experimental verification shows that in silty seabed soil, the horizontal bearing capacity and pull-out resistance of the anchor body of this invention are significantly improved compared to traditional fixed-size suction anchors.

[0021] 3. Strong environmental adaptability: This invention can adjust the penetration depth and negative pressure of the inner cylinder according to different seabed soil conditions, water depth, and engineering load requirements. It is suitable for various seabed environments such as soft clay, silt, fine sand, and sandy soil, and has good engineering adaptability. Through the coordinated anchoring of the inner and outer cylinders, the contact area between the anchor body and the soil is expanded, promoting the formation of a passive soil wedge, optimizing the load transfer path, and improving the side friction and end resistance of the anchor body, effectively resisting the cyclic loads of tides and waves on offshore wind power, floating structures, and other facilities.

[0022] 4. Simple structure and convenient construction: The overall structure of this invention is simple, requiring no complex drive system. Each component can adopt a standardized design, which facilitates processing, manufacturing, installation and construction, as well as subsequent maintenance, and has good engineering promotion value.

[0023] 5. Excellent Engineering Application Prospects: Existing improved suction anchors (such as those with added baffles, fins, barbs, etc.) do not involve telescopic structure design, making it impossible to flexibly adjust the anchor body size and still presenting problems in balancing installation and load-bearing capacity. The core innovation of this invention lies in the telescopic structure and collaborative control method, breaking through the limitations of traditional fixed-size designs. It eliminates the need for complex reinforcing components; significant performance improvements can be achieved simply through structural and methodological optimization. Furthermore, the structure is simpler, the cost is lower, and it is irreplaceable. This invention can be widely applied in offshore wind power, floating platforms, floating production storage and offloading (PSA) units, and deep-sea mooring engineering, meeting the requirements of deep-water marine engineering for high-load-bearing and high-stability anchoring foundations. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall structure of the telescopic suction anchor of Embodiment 1 of the present invention. Figure 1 ; Figure 2 This is a schematic diagram of the overall structure of the telescopic suction anchor of Embodiment 1 of the present invention. Figure 2 (Mooring service phase); Figure 3 yes Figure 1 Enlarged view of a portion of point A in the middle; Figure 4 This is a flowchart of the installation and retrieval method of the telescopic suction anchor according to Embodiment 2 of the present invention; Figure 5 This is a schematic diagram of the installation and retrieval method of the telescopic suction anchor according to Embodiment 2 of the present invention; Figure 6This is a schematic diagram comparing the numerical simulation results of the bearing capacity of the suction anchor and the single suction anchor of the present invention. (a) is the curve of horizontal bearing capacity and displacement relationship between the telescopic suction anchor and the single suction anchor; (b) is the curve of normalized horizontal bearing capacity and displacement relationship between the telescopic suction anchor and the single suction anchor; (c) is the curve of vertical bearing capacity and displacement relationship between the telescopic suction anchor and the single suction anchor; and (d) is the curve of normalized vertical bearing capacity and displacement relationship between the telescopic suction anchor and the single suction anchor.

[0025] In the above figures: 1. Outer cylinder; 2. Inner cylinder; 3. Fixed sealing device; 31. Sealing seat; 32. Sealing ring; 33. Locking mechanism; 4. Circular through hole; 5. Negative pressure suction and discharge pipeline; 6. Pressure sensor; 7. Reversing shut-off valve; 8. Water pump; 9. Limit block; 10. Mooring point; 11. Anchor chain. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," 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, and therefore should not be construed as a limitation of the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0028] It should be noted that when a component is said to be "attached" to another component, it can be directly on the other component or it can be in the middle of another component. When a component is said to be "set" to another component, it can be directly set to the other component or it may also be in the middle of another component. When a component is said to be "fixed" to another component, it can be directly fixed to the other component or it may also be in the middle of another component.

[0029] It should also be noted that, unless otherwise explicitly specified and limited, the terms "setup" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "or / and" as used herein includes any and all combinations of one or more of the associated listed items.

[0031] like Figures 1-3 As shown, the present invention proposes a telescopic suction anchor, the key improvement of which is that by setting a telescopic inner cylinder and a staged penetration mechanism, the suction anchor adopts different force modes in the installation stage and the service stage, thereby realizing functional decoupling between the installation stage and the service stage.

[0032] During the installation phase, the outer cylinder first penetrates the seabed soil under negative pressure. After the outer cylinder reaches the predetermined penetration depth, the fixing restrictions between the inner and outer cylinders are released, allowing the inner cylinder to continue penetrating the seabed soil under negative pressure, thus forming a phased penetration mode of "outer cylinder first, inner cylinder later".

[0033] Unlike the traditional method of synchronously penetrating suction anchors, this invention releases the penetration resistance that was originally developed synchronously through staged penetration, avoiding a synchronous increase in the resistance of all structures in the later stages of installation. This reduces the peak negative pressure requirement during the installation stage and improves the installation feasibility of large suction anchors in deep water environments.

[0034] During service, the inner and outer cylinders work together to transfer loads. By expanding the contact area between the anchor and the soil and enhancing the constraint effect of the surrounding soil, the overall bearing capacity of the suction anchor and its stability under complex combined load conditions are improved.

[0035] The telescopic suction anchor includes an anchor body, which comprises an outer cylinder and an inner cylinder. The telescopic suction anchor also includes a fixing and sealing device, a negative pressure device, and a mooring device. The inner cylinder is nested inside the outer cylinder and can extend and retract axially relative to the outer cylinder. The fixing and sealing device is located between the inner and outer cylinders, used to achieve a fixed connection, relative movement switching, and sealing isolation between the inner and outer cylinders. The negative pressure device communicates with the sealed space inside the anchor body, providing pressure power for the insertion and retrieval of the suction anchor. The mooring device is located on the anchor body and is used to connect to a marine engineering mooring system.

[0036] The main components are described below.

[0037] 1. Outer cylinder: The outer cylinder serves as the basic load-bearing component of the anchor body. It is open at the bottom and closed at the top, and can be cylindrical, polygonal, or other structural forms adapted to the needs of marine engineering.

[0038] The outer cylinder can be made of high-strength, corrosion-resistant materials to meet the structural strength and durability requirements of deep-sea environments. A through-hole is provided at the top of the outer cylinder for installing and fixing sealing devices and the inner cylinder; mooring connections are provided on the side walls of the outer cylinder for connecting to anchor chains or mooring systems to meet the mooring needs of offshore wind power, floating platforms, and other marine engineering facilities.

[0039] In this embodiment, the outer cylinder 1 is made of high-strength corrosion-resistant steel, with an overall cylindrical structure, a diameter of 10m, a length of 10m, a wall thickness of 100mm, an open bottom, and a closed top. A through hole with a diameter of 5.2m is pre-reserved at the center of the top of the cylinder. Mooring points 10 are provided on the side wall of the outer cylinder 1. The mooring points 10 are fixed by double-sided welding, and anti-slip grooves are provided at the connection points with the anchor chain 11 to ensure that the anchor chain 11 does not slip during mooring.

[0040] 2. Inner cylinder: The inner cylinder is nested inside the outer cylinder, and its outer diameter is smaller than the size of the through hole at the top of the outer cylinder, allowing it to extend and retract vertically relative to the outer cylinder. The inner cylinder can be a hollow structure, closed at the top and open at the bottom, and its length can be adjusted according to seabed conditions, penetration depth, and engineering requirements. A negative pressure connection through hole is provided at the top of the inner cylinder for sealing connection with a negative pressure device to form a closed negative pressure environment.

[0041] Specifically, a limiting structure can be set on the outer side of the inner cylinder to limit the maximum expansion and contraction position of the inner cylinder relative to the outer cylinder, preventing the inner cylinder from excessively extending or contracting, which could lead to structural instability.

[0042] In this embodiment, the inner cylinder 2 is made of the same material as the outer cylinder, and is a cylindrical hollow structure with a diameter of 5m and a length of 15m. Two limiting blocks 9 are provided at the top and end of the outer side of the inner cylinder 2. The limiting blocks are 50mm high and are used to limit the extreme position of the inner cylinder 2's extension and contraction to prevent the inner cylinder 2 from over-extending or over-contracting. A circular through hole 4 with a diameter of 100mm is opened on one side of the top of the inner cylinder 2 for sealing connection with the negative pressure suction and discharge pipeline of the negative pressure device.

[0043] 3. Fixed sealing device: A fixed sealing device is installed between the top through-holes of the inner and outer cylinders to achieve a sealed connection and relative movement control between them. This device maintains sealing performance while switching between two working states: "fixed connection" and "free expansion and contraction." When the outer cylinder is fully inserted, the fixed sealing device locks the relative movement between the inner and outer cylinders, ensuring synchronous insertion. As the inner cylinder continues to penetrate, the fixed restriction is released, allowing it to continue expanding and contracting downwards under negative pressure while maintaining the sealing performance between the inner and outer cylinders.

[0044] The fixed sealing device can be hydraulic, electromagnetic, or other structural forms that can achieve locking and unlocking functions.

[0045] In this embodiment, the fixed sealing device 3 includes a sealing seat 31, a sealing ring 32, a locking mechanism 33, and a control component. The sealing seat 31 is generally annular, made of 304 stainless steel, and welded to the through-hole at the top of the outer cylinder 1 to achieve a static seal between them. A sealing ring 32 is disposed on the inner circumference of the sealing seat 31, axially aligned with the outer wall of the inner cylinder, forming a sealing barrier to achieve a sealed connection between the sealing seat 31 and the inner cylinder 2. In this embodiment, the sealing ring 32 has a cross-sectional diameter of 200 mm. The locking mechanism 33 is fixedly connected within the sealing seat 31 and locks and unlocks the inner cylinder 2 via the control component.

[0046] In this embodiment, the locking mechanism 33 is set as a ring electromagnet, and correspondingly, the inner cylinder 2 is made of a ferromagnetic material. The control component is an electromagnet controller, integrated into the control system of the suction anchor; the electromagnet controller de-energizes the electromagnet, releasing the electromagnet's restriction on the vertical movement of the inner cylinder 2, and energizes the electromagnet to re-lock the inner cylinder 2, restricting its vertical movement. The aforementioned sealing seat, sealing ring, locking mechanism, and control component structures and control principles all adopt conventional technical means in the field, and are not the core innovation of this invention, therefore they will not be elaborated upon.

[0047] 4. Negative pressure device: The negative pressure device, serving as the power source for the suction anchor insertion, includes a water pump 8, a negative pressure suction and discharge pipeline 5, a reversing shut-off valve 7, and a pressure sensor 6. The power of the water pump is designed according to the anchor body size to generate a stable negative pressure. One end of the negative pressure suction and discharge pipeline is sealed to the through hole at the top of the inner cylinder, and the other end is connected to the water pump and the pressure sensor. A reversing shut-off valve is installed on the pipeline, enabling bidirectional functions of water suction insertion and water injection recovery through valve switching. The pressure sensor monitors the negative pressure value in the sealed chamber in real time, and the negative pressure value can be automatically adjusted through the control system to ensure a smooth insertion process.

[0048] In this embodiment, the negative pressure suction and discharge pipeline 5 is a high-pressure rubber tube with an inner diameter of 100mm. One end is sealed to the flange of the top through hole of the inner cylinder 2, and the other end is connected to the pressure sensor 6 and the water pump 8. A reversing shut-off valve 7 is provided on the pipeline to switch the water flow direction. Suction creates negative pressure to achieve penetration, and water injection balances the pressure to achieve recovery. The accuracy of the pressure sensor is ±0.01MPa.

[0049] 5. Mooring apparatus: The mooring apparatus includes mooring points and anchor chains. Mooring points are located on the sidewall or top of the outer cylinder and are used to connect to the marine engineering mooring system; the anchor chains can be made of high-strength, corrosion-resistant materials and can be equipped with anti-derailment structures to improve long-term service stability.

[0050] In this embodiment, the mooring point 10 and the outer cylinder 1 are integrally welded, and the anchor chain 11 is a high-strength anti-corrosion anchor chain; the connecting joint adopts a detachable flange structure, and anti-detachment pins are set to prevent the anchor chain from falling off under the action of marine environmental loads.

[0051] The telescopic suction anchor of the present invention achieves functional separation between the installation and service phases by having the inner and outer cylinders work together, the inner cylinder realizes phased telescopic penetration, the fixed sealing device realizes structural switching and sealing control, the negative pressure device provides penetration and recovery power, and the mooring device realizes anchoring connection of marine structures.

[0052] like Figures 4-5 As shown, based on the above-mentioned telescopic suction anchor, the present invention also provides a method for installing and retrieving a telescopic suction anchor, the specific process of which is as follows: 1. Preliminary preparation: Check the integrity and performance of each component of the telescopic suction anchor, and verify the sealing performance of the fixed sealing device 3 through an airtightness test; check the operation status of the water pump 8, reversing shut-off valve 7, and pressure sensor 6 of the negative pressure device to ensure that there are no faults; check the connection reliability of the mooring device to ensure that there are no cracks in the welded parts and no damage to the anchor chain 11; retract the inner cylinder 2 into the outer cylinder 1, and lock the inner cylinder 2 with the electromagnet of the fixed sealing device 3 to ensure that the top of the inner cylinder 2 is flush with the top of the outer cylinder 1, thereby reducing the volume of transportation and hoisting.

[0053] 2. Step 1 (Self-weight penetration): Use specialized hoisting equipment to hoist the telescopic suction anchor to the designated anchoring area; keep the anchor body vertical during hoisting to avoid tilting and collision; adjust the anchor body position to ensure that the center of the anchor body coincides with the designed anchoring point; slowly release the hoisting ropes so that the anchor body slowly penetrates into the seabed soil under its own weight, ensuring that the bottom of the anchor body is in close contact with the seabed soil to initially form a sealed space; monitor the anchor body attitude in real time during the penetration process to keep it vertical and without tilting.

[0054] 3. Step 2 (Suction Penetration of Outer Cylinder 1): After the anchor body is driven into place by its own weight, observe the contact between the bottom of the anchor body and the soil to confirm the formation of a sealed space; monitor the pressure in the chamber through pressure sensor 6. If the pressure remains constant and there is no significant drop, it indicates good sealing; turn on the water pump 8 of the negative pressure device and open the reversing shut-off valve 7 of the negative pressure suction and discharge pipeline 5 to start pumping seawater from the sealed chamber. Monitor the negative pressure value in real time through pressure sensor 6 and slowly adjust the power of water pump 8 to stabilize the negative pressure value; under the combined action of negative pressure driving force and its own weight, outer cylinder 1 penetrates into the seabed soil at a constant speed. During the penetration process, continuously monitor the negative pressure value and the anchor body attitude, and record the negative pressure value every 5 minutes to ensure that the negative pressure is stable and the anchor body remains vertical; until outer cylinder 1 is completely penetrated into the seabed soil (the top of the outer cylinder is flush with the seabed surface), stop water pump 8 and close reversing shut-off valve 7 to complete the suction penetration of outer cylinder 1.

[0055] 4. Step 3 (Inner Cylinder 2's Suction Penetration): After the outer cylinder 1 is inserted into place, the electromagnet controller of the fixed sealing device 3 is used to de-energize the electromagnet, releasing the electromagnet's restriction on the vertical movement of the inner cylinder 2. At the same time, the sealing performance of the fixed sealing device 3 is checked, and the pressure remains stable with no negative pressure leakage. The water pump 8 is restarted, the negative pressure value is adjusted and kept stable, and the inner cylinder 2 continues to penetrate slowly into the seabed soil under the action of negative pressure driving force. During the penetration process, the extension length of the inner cylinder is monitored in real time, and the penetration speed is controlled according to the penetration depth set in the project. When the extension length of the inner cylinder reaches 10m, the water pump 8 and the reversing shut-off valve 7 are turned off, and the inner cylinder 2 is re-locked by energizing the electromagnet, restricting its vertical movement. The negative pressure value in the sealed chamber is checked again, and the negative pressure is kept stable for 30 minutes without leakage, indicating that the inner cylinder 2 is inserted into place and anchored reliably.

[0056] 6. Step 4 (Recycling of the Suction Anchor): After the telescopic suction anchor reaches its service life or needs to be replaced, initiate the recycling process; check the performance of the negative pressure device and the fixed sealing device to ensure normal operation of the equipment; open the reversing shut-off valve 7 of the negative pressure device, and slowly inject seawater into the sealed chamber through the negative pressure suction and discharge pipeline 5, monitoring the pressure in the chamber in real time until the pressure is consistent with the external seawater pressure, and release the negative pressure state; after the pressure is balanced, use hoisting equipment to slowly lift the anchor body. If there is a large resistance from the soil during the pulling process, inject high-pressure seawater into the chamber to assist in pulling out the anchor body; after the anchor body is completely pulled out, clean the soil and debris on the surface of the anchor body, check the wear of each component, replace the worn sealing ring 32, and perform sandblasting and anti-corrosion coating treatment on the surface of the anchor body; fix the inner cylinder 2 to the top of the outer cylinder 1 and lock it with the fixed sealing device 3 for easy reuse in the future.

[0057] 6. Step 5 (Recycling of the Suction Anchor): After the telescopic suction anchor reaches its service life or needs to be replaced, initiate the recycling process; check the performance of the negative pressure device and the fixed sealing device to ensure normal operation of the equipment; open the reversing shut-off valve 7 of the negative pressure device, and slowly inject seawater into the sealed chamber through the negative pressure suction and discharge pipeline 5, monitoring the pressure in the chamber in real time until the pressure is consistent with the external seawater pressure, and release the negative pressure state; after the pressure is balanced, use hoisting equipment to slowly lift the anchor body. If there is a large resistance from the soil during the pulling process, inject high-pressure seawater into the chamber to assist in pulling out the anchor body; after the anchor body is completely pulled out, clean the soil and debris on the surface of the anchor body, check the wear of each component, replace the worn sealing ring 32, and perform sandblasting and anti-corrosion coating treatment on the surface of the anchor body; fix the inner cylinder 2 to the top of the outer cylinder 1 and lock it with the fixed sealing device for easy reuse in the future.

[0058] See Figure 6 A schematic diagram comparing the numerical simulation results of the bearing capacity of a suction anchor and a single suction anchor. Figure 6 (a) Schematic diagram of the relationship between horizontal bearing capacity and displacement of telescopic suction anchor and single suction anchor: where L 2 indicates the length of the inner cylinder. D 2 indicates the inner cylinder diameter. D 2 = 5m, L 2 / D 2 represents the length-to-diameter ratio of the variable inner cylinder length. L 2 / D 2=0 corresponds to a single suction anchor (diameter) D =10m, length L =10m), L 2 / D 2 = 2.5 and 3 represent L 2 = 12.5m and 15m, corresponding to D L1 = 10m, L2 = 10m; Figure 6 (b) shows the normalized horizontal bearing capacity versus displacement curves for telescopic suction anchors and single suction anchors: H ult This indicates the corresponding ultimate horizontal bearing capacity. γ ′ Indicates the effective unit weight of the soil; Figure 6 (c) shows the relationship curves between the vertical bearing capacity and displacement of the telescopic suction anchor and the single suction anchor; Figure 6 (d) illustrates the normalized vertical bearing capacity versus displacement curves for telescopic suction anchors and single suction anchors: V ult This indicates the corresponding ultimate vertical bearing capacity.

[0059] Depend on Figure 6Numerical simulations have verified that the telescopic suction anchor and its installation and retrieval method proposed in this invention can effectively improve the overall load-bearing capacity of the suction anchor and enhance structural stability under complex load conditions. Compared with traditional fixed-size suction anchors, this embodiment shows significant improvements in both horizontal load-bearing capacity and pull-out resistance, meeting the high-load anchoring requirements of deep-sea offshore wind power and other projects.

[0060] The embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A telescopic suction anchor, comprising an anchor body, characterized in that, The anchor body includes an outer cylinder and an inner cylinder. The telescopic suction anchor also includes a fixing and sealing device, a negative pressure device, and a mooring device. The inner cylinder is nested inside the outer cylinder and can move telescopically relative to the outer cylinder along the axial direction. The fixing and sealing device is located between the inner and outer cylinders and is used to achieve a fixed connection, relative movement switching, and sealing isolation between the inner and outer cylinders. The negative pressure device is connected to the sealed space inside the anchor body and provides pressure power for the insertion and retrieval of the suction anchor. The mooring device is located on the anchor body and is used to connect with the marine engineering mooring system.

2. The telescopic suction anchor according to claim 1, characterized in that, The fixed sealing device has two working states. In the first state, it locks the relative movement of the inner cylinder and the outer cylinder and keeps them sealed. In the second state, it releases the restriction on the relative movement of the inner cylinder and the outer cylinder while continuously maintaining the seal between the inner and outer cylinders.

3. The telescopic suction anchor according to claim 1, characterized in that, The outer and inner cylinders are installed in a phased penetration manner. The outer cylinder penetrates the seabed soil first, and then the inner cylinder continues to penetrate downwards to achieve phased release of penetration resistance.

4. The telescopic suction anchor according to claim 1, characterized in that, The fixed sealing device includes a sealing seat, a sealing ring, a locking mechanism, and a control component. The sealing seat is located at the through hole at the top of the outer cylinder and is welded to the outer cylinder for sealing. The sealing ring is located inside the sealing seat to achieve a sealed connection between the sealing seat and the inner cylinder. The locking mechanism is fixedly connected inside the sealing seat, and the locking mechanism achieves locking and unlocking of the inner cylinder through the control component.

5. The telescopic suction anchor according to claim 4, characterized in that, The locking mechanism is set to an electromagnet; the inner cylinder is made of ferromagnetic material.

6. The telescopic suction anchor according to claim 1, characterized in that, The inner and outer cylinders work together to transfer loads during service, thereby improving the overall load-bearing capacity of the suction anchor and its structural stability under complex load conditions.

7. The telescopic suction anchor according to claim 1, characterized in that, The negative pressure device includes a water pump, a negative pressure suction and discharge pipeline, a reversing shut-off valve, and a pressure sensor. One end of the negative pressure suction and discharge pipeline is sealed to the through hole at the top of the inner cylinder, and the other end is connected to the water pump and the pressure sensor. A reversing shut-off valve is installed on the negative pressure suction and discharge pipeline to achieve the bidirectional function of water suction penetration and water injection recovery through valve switching. The pressure sensor monitors the pressure inside the anchor body cavity in real time to match the pressure requirements of penetration and recovery conditions.

8. A method for installing and retrieving a telescopic suction anchor, characterized in that, The telescopic suction anchor applied to any one of claims 1 to 7 comprises the following steps: Step 1: Penetration by overall self-weight: Under the action of the anchor body's own weight, the suction anchor initially penetrates into the seabed soil; Step 2, suction penetration of the outer cylinder: After the bottom of the telescopic suction anchor forms a closed space with the seabed soil, the negative pressure device is activated. Under the action of negative pressure, the outer cylinder and the inner cylinder are synchronously penetrated into the seabed soil. Step 3, suction penetration of the inner cylinder: After the outer cylinder reaches the predetermined penetration depth, release the restriction of the vertical movement of the inner cylinder by the fixing sealing device, while maintaining the sealing state between the inner and outer cylinders; continue to start the negative pressure device, so that the inner cylinder continues to penetrate into the seabed soil under the action of negative pressure until the set penetration depth is reached. Step 4, Mooring of the suction anchor: After the telescopic suction anchor is installed, the suction anchor is connected to the mooring structure through the mooring device to anchor offshore wind power, floating platforms and other marine engineering facilities. Step 5, Recovery of the suction anchor: When the suction anchor reaches the end of its service life or needs to be repositioned, water is injected into the anchor body through a negative pressure device to change the pressure difference between the inside and outside of the anchor body. Under the action of water pressure, the inner and outer cylinders gradually detach from the seabed soil, thereby realizing the overall recovery of the suction anchor.

9. The installation and recycling method according to claim 8, characterized in that, In steps 1 and 2, the fixed sealing device locks the relative movement between the inner and outer cylinders and maintains the sealing performance between the inner and outer cylinders.

10. The installation and recycling method according to claim 8, characterized in that, Steps 2 and 3 utilize a phased penetration method of "penetrating the outer cylinder first and then the inner cylinder" to achieve phased release of penetration resistance during the installation phase.

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