Ultra-large single-pile offshore construction method

Abstract

The present invention discloses a method for offshore construction of an extra-large single pile: by using a full-rotation crane vessel, a jack-up pile-stabilizing platform, a set of main hoisting ropes of a balance beam, and a set of auxiliary hoisting ropes of a pile-turning clamp, and adopting the method of single-vessel single-hook stern lifting, the offshore construction of the extra-large single pile is realized. Among them, the main and auxiliary hoisting riggings of the single pile are installed by berthing the transport ship parallel to the crane vessel, and the transport ship is rotated to the stern position convenient for the crane vessel to lift through the main hoisting machine and cable ropes of the crane vessel, so as to realize the lifting, turning over and pile driving of the extra-large single pile, giving full play to the construction flexibility of the crane of an ordinary full-rotation crane vessel and the lifting capacity of the fixed stern lifting of the crane, alleviating the contradiction of the shortage of construction vessels and machinery for extra-large single piles in China, and optimizing the single-pile construction process to improve work efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of offshore wind power, and particularly to a construction method for an extra-large monopile in the sea. Background Art

[0002] The monopile foundation is one of the most common structures for offshore wind turbine foundations. Due to its simple structure and relatively mature technology, the monopile foundation is widely used in offshore wind farms. With the development of the large-scale of wind turbine capacity, the average capacity of wind turbines has increased from 5 MW to 10 MW and 12 MW. The size and weight of the monopile foundation have also increased accordingly, developing from the level of 1000 t pile weight to the extra-large monopile of 2500 t level. Therefore, it brings greater challenges to offshore construction.

[0003] At present, the relatively mature monopile turning construction technology is mainly divided into three categories. One is the turning construction using the stern lifting method by a fixed boom crane ship. This method has low construction efficiency and high requirements for weather and sea conditions.

[0004] The second is to use a full-rotation boom crane ship and two ships cooperate to lift and turn the pile. This method requires two crane ships to achieve turning. At the same time, since the above two ships are arranged in a T shape, the sea winds and ocean currents faced by the two ships are different. It is easy to collide when the two ships are close. The construction cost and requirements for weather and sea conditions are high. The more difficult the cooperation, the easier it is to have safety accidents such as collisions, reducing the safety.

[0005] The third is to use a full-rotation crane ship for single-ship single-hook turning construction. At present, the number of large floating crane ships in the 4000t - 5000t level in China is very small. For example, for a 4000t-level floating crane ship, its maximum full-rotation lifting capacity is only 2000t, and the safe lifting capacity of the crane decreases with the increase of the lifting span. Therefore, for the extra-large monopile of 2500t level, according to the existing conventional side full-rotation lifting construction technology, most floating crane ships cannot meet the lifting weight requirements. Summary of the Invention

[0006] In order to solve the existing problems in the technical background, the present invention provides a construction method for an extra-large monopile in the sea.

[0007] The present invention adopts the following technical solutions: The key construction instruments mainly include a full-rotation crane ship, a jack-up pile stabilization platform, a set of main hoisting ropes of a balance beam, and a set of auxiliary hoisting ropes of a pile turning clamp.

[0008] The full-rotation crane ship has the following remarkable features: It has a main hook, a deputy hook, and a small hook, and the three hooks are distributed in a straight line. The main hook is a cross-shaped four-claw lifting hook.

[0009] The bottom - sitting pile - stabilizing platform has the following remarkable features: The pile - stabilizing platform sits on the seabed mud surface and has two layers of expandable annular holding arms, with 4 sets of hydraulic jacks evenly distributed on each layer of holding arms. The pile - stabilizing platform is equipped with high - precision GPS positioning equipment, which can display the planar position and direction of the pile - stabilizing platform in real - time on a computer.

[0010] The remarkable features of the pile - turning auxiliary sling: The sling steel wire rope is segmented, and the middle of the sling steel wire rope is connected with a shackle. According to the different lengths of single piles, by adjusting the length of the sling steel wire rope, the change of the included angle α between the pile axis and the horizontal plane after the single pile is lifted is controlled.

[0011] The specific construction method includes the following steps:

[0012] S1. The crane ship sails to the preset position, positions itself according to the principle of heading against the current in the actual water flow direction of the wind farm, and throws out the positioning anchors for positioning.

[0013] S2. Use the crane ship to install the pile - stabilizing platform. After the crane ship hoists the pile - stabilizing platform and completes the positioning, according to the data real - time feedback by the high - precision GPS positioning equipment on the pile - stabilizing platform, adjust the planar position and orientation of the pile - stabilizing platform through the crane, so that the pile - stabilizing platform is installed at the set position on the stern side of the crane ship, the center of the holding arm coincides with the center of the machine position, and open the upper and lower holding arms on the pile - stabilizing platform.

[0014] S3. Berth the transport ship. There is a single pile placed on the transport ship. Berth it parallel to the side of the crane ship, with the bottom of the single pile facing the bow of the crane ship.

[0015] S4. Hang one end of the main sling on the two symmetric hook teeth of the main hook of the crane, hang the auxiliary sling on another hook tooth of the main hook, and connect the shackle in the middle of the auxiliary sling to hang on the small hook; The small hook is connected to the shackle of the auxiliary sling to assist the auxiliary sling in unhooking. The crane rotates to above the bottom of the single pile, installs the pile - turning clamp on the upper side of the bottom of the single pile with the small hook, and fixes the pile - turning clamp to the ear preset on the outer wall of the pile bottom with a safety pin; The crane rotates to above the lifting lug of the single pile and hangs the main sling on the lifting lug of the single pile.

[0016] S5. Slowly transfer the transport ship to the stern. There is a cable connected between the crane ship and the transport ship. Use the rotation of the crane to drive the transport ship under the single pile to move slowly; The cable winch can take in and pay out the cable to control its tightness state and keep the transport ship stable during the rotation movement process.

[0017] S6. Release the fixation of the single pile on the transport ship and the safety pin on the pile - turning clamp. The crane hoists the main hook to make the main sling and the auxiliary sling gradually bear force. After the single pile is lifted off the transport ship, the transport ship leaves the berth using the natural water flow.

[0018] S7. The main hook of the crane descends. As the single pile is gradually immersed in the water until the bottom of the pile touches the mud, the auxiliary sling becomes slack and is not under force. The auxiliary hook is lifted, driving the shackle to disengage the auxiliary sling from the teeth of the main hook. The main hook of the crane continues to lift, and the single pile flips to a vertical state, during which the pile turning tongs automatically disengages from the bottom of the pile under the action of gravity. The small hook of the crane is lifted to retrieve the auxiliary sling and the pile turning tongs at its end.

[0019] S8. The hoisting vessel hauls in the anchor and approaches the pile stabilizing platform, and places the single pile within the clamping arms of the pile stabilizing platform.

[0020] S9. Keep the single pile perpendicular to the horizontal plane and let it sink into the mud under its own weight. Close the lower clamping arm to hold the outer wall of the single pile. According to the measured verticality data of the single pile, judge its inclination direction, and adjust the telescopic distance of the hydraulic jacks on the upper clamping arm to adjust the verticality of the single pile. The main hook of the crane descends to let the single pile sink into the mud under its own weight. During the process of sinking into the mud, repeatedly measure the verticality of the single pile and adjust the jacks to ensure that the verticality meets the requirements.

[0021] S10. Adjust the position of the hoisting vessel so that the pile stabilizing platform is located on the side, facilitating the operation of the hydraulic hammer.

[0022] S11. Lift the hydraulic hammer to drive the single pile to sink to the design elevation.

[0023] Preferably, in step S6, after the single pile is lifted, the main sling, the auxiliary sling, and the axis of the single pile form an obtuse triangle, and the angle α between the pile axis and the horizontal plane is between 8 and 16 degrees.

[0024] Preferably, step S4 further includes adding cushion woods or tooling at the tail of the transport ship.

[0025] Preferably, the main hook, the auxiliary hook, and the small hook are arranged in a straight line, and the main hook is a cross-shaped four-claw lifting hook.

[0026] Preferably, the pile stabilizing platform sits on the seabed mud surface. The upper clamping arm and the lower clamping arm are annular. There are 4 sets of hydraulic jacks evenly distributed on the upper clamping arm and the lower clamping arm respectively. The pile stabilizing platform is equipped with high-precision GPS positioning equipment, which can display the planar position and direction of the pile stabilizing platform on a computer in real time.

[0027] Preferably, the auxiliary sling can be changed. The sling steel wire rope of the auxiliary sling is segmented, and the middle of the sling steel wire rope is connected with a shackle.

[0028] Beneficial effects:

[0029] 1. Single-vessel construction is adopted, avoiding double-vessel lifting, effectively reducing the difficulty of multi-vessel coordination and the construction cost of ship machinery equipment.

[0030] 2. Give full play to the performance of the fixed stern crane of the general full-rotation crane ship to alleviate the shortage of super-large single-pile construction machinery in China.

[0031] 3. Give play to the flexible advantage of the crane of the full-rotation crane ship, and use the side-berthing method of the transport ship to install the slings and riggings, so that the crane ship and the transport ship are in a parallel state. At this time, the ocean currents and swells faced by the above two ships are the same, making the motion states of the two ships synchronous. Compared with the T-shaped berthing method at the stern of the ship, the operation safety factor and construction efficiency are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is the positioning diagram of the crane ship and the transport ship of the present invention;

[0033] Figure 2 is the hook diagram of the rigging of the present invention;

[0034] Figure 3 is the connection diagram of the rigging of the present invention;

[0035] Figure 4 is the installation diagram of the pile-turning tongs of the present invention;

[0036] Figure 5 is the schematic diagram of single-pile lifting of the present invention;

[0037] Figure 6 is the schematic diagram of the transfer of the transport ship of the present invention;

[0038] Figure 7 is the schematic diagram of the stern berthing of the transport ship of the present invention;

[0039] Figure 8 is the diagram of the single pile self-weight entering the mud of the present invention;

[0040] Figure 9 is the schematic diagram of the crane ship side-berthing the pile-stabilizing platform of the present invention.

[0041] In the figure: 1 - crane ship; 2 - crane; 21 - main hook; 22 - auxiliary hook; 23 - small hook; 3 - transport ship; 4 - single pile; 5 - pile-stabilizing platform; 511 - upper clamping arm; 512 - lower clamping arm; 6 - main lifting cable; 7 - auxiliary lifting cable; 71 - pile-turning tongs; 72 - shackle; 73 - safety pin; 8 - anchor cable; 9 - cable; 10 - cushion wood. DETAILED DESCRIPTION OF THE INVENTION

[0042] The present invention will be further described in detail below with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present invention, rather than limiting the present invention. Additionally, it should be noted that for the convenience of description, only the parts related to the present invention are shown in the drawings, rather than all the structures.

[0043] In the description of the present invention, unless otherwise clearly defined and limited, the terms "connected", "connected to", and "fixed" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral body; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0044] In the present invention, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features between them. Moreover, the first feature being "above", "over", and "on" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "under", and "beneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely indicates that the horizontal height of the first feature is lower than that of the second feature.

[0045] In the description of this embodiment, the orientation or positional relationships such as "above", "below", "right", etc. are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of description and simplifying the operation, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, so it cannot be understood as a limitation to the present invention. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0046] When the transport ship and the crane ship for transporting a single pile are connected to the single pile on the ocean surface in a T shape, due to the different ocean currents faced by the above two ships, the two ships are prone to collision accidents; because lifting from the ship's side requires a relatively large floating crane ship, but the number of large floating crane ships in the 4000t - 5000t level in China is very small, and the cost of waiting for the above large floating crane ships is relatively high.

[0047] To solve the above problems, the present invention provides a method for super-large single-pile offshore construction, as Figures 1 to 8 shown, which includes the following steps:

[0048] S1, the crane ship 1 first positions itself. According to the principle of facing the current in the bow direction according to the actual water flow direction of the wind farm, 6 - 8 positioning anchors are thrown for positioning. Usually, there are 3 anchors in the bow and 2 to 3 anchors in the stern, and the length of the anchor cable is 800 - 1000m. If it is a ship with a dynamic positioning system (DP-2), the DP-2 method can be used for positioning. The above positioning method is a prior art and will not be elaborated here.

[0049] S2: Install the pile stabilizing platform 5. After the crane vessel 1 hoists the pile stabilizing platform 5 and completes the positioning on site, according to the data real-time feedback by the high-precision GPS positioning equipment on the pile stabilizing platform 5, adjust the plane position and orientation of the pile stabilizing platform 5 through the crane 2, so that the pile stabilizing platform 5 is installed at the set position on the stern side of the crane vessel 1, and the center of the clamping arm coincides with the center of the machine position; open the upper and lower clamping arms of the pile stabilizing platform 5; then the crane vessel 1 hauls the anchor towards the bow direction, away from the pile stabilizing platform 5, to facilitate the cooperation with the transport ship 3.

[0050] S3: Berth the transport ship 3. The transport ship 3 floats and transports the single pile 4, and berths parallel to the side of the crane vessel 1, so that the bottom of the single pile 4 faces the bow of the crane vessel 1.

[0051] S4: Install the slings and riggings for turning over the single pile 4, including the main sling 6 of the balance beam, the sub-sling 7 of the pile turning tongs 71. First, operate on the deck of the crane vessel 1 in advance, hang the upper two lifting points of the main sling 6 of the balance beam on two symmetric hook teeth of the main hook 21 of the crane vessel 1, and hang the upper lifting point of the sub-sling 7 on the pile turning tongs 71 on another hook tooth of the main hook 21; connect the middle of the sub-sling 7 with a shackle 72 and hang it on the small hook 23; connect the sub-hook 22 with a shackle 72 and flexibly buckle it on the upper section of the sub-sling 7 to assist the sub-sling 7 in unhooking; rotate the crane 2 above the bottom of the single pile 4, use the small hook 23 to install the pile turning tongs 71 on the upper side of the bottom of the single pile 4, and use the safety pin 73 to fix the pile turning tongs 71 to the lug preset on the outer wall of the pile bottom; rotate the crane 2 above the lifting lug of the single pile 4, hang the sling of the main sling 6 on the lifting lug of the single pile 4, and set up a strengthening tooling or a spacer 10 at the tail of the deck of the transport ship 3. Through the above steps, when the crane vessel 1 and the transport ship 3 are in a parallel state, the connection between the crane 2 and the single pile 4 is realized. Since the two vessels are in a parallel state, the ocean currents and sea conditions faced by the two vessels are relatively close, and the motion states of the two vessels are the same, which improves the safety of connecting the crane 2 and the single pile 4. The main hook 21, the sub-hook 22 and the small hook 23 are distributed in a straight line, and the sling steel wire rope of the present invention is segmented, and the middle of the sling steel wire rope is connected with a shackle. According to the different lengths of the single pile, by adjusting the length of the sling steel wire rope, control the change of the angle α between the pile axis and the horizontal plane after the single pile is lifted. The main sling 6, the sub-sling 7 and the single pile axis form an obtuse triangle, and the angle α between the pile axis and the horizontal plane after the single pile 4 is lifted is between 8 and 16 degrees. If the angle α is too small, it will be difficult for the sub-sling to unhook. If the angle α is too large, the single pile will slide between the single pile and the transport ship during the pile turning process.

[0052] S5: Slowly transfer the transport ship 3 to the stern of the ship and tighten the mooring rope 9. During the transfer process, use the crane 2 to rotate and control the slow movement of the transport ship 3; the capstan can control the tightness of the high-strength mooring rope 9 at any time. Since the crane ship 1 used in the present invention cannot lift by the method of side lifting on the ship's side, the transport ship 3 is fixed near the crane ship 1 through the mooring rope 9. At the same time, the single pile 4 is dragged by the crane 2. Since the single pile 4 is bound to the transport ship 3, the transport ship 3 will be driven to rotate towards the stern of the crane ship 1, and finally the crane ship 1 and the transport ship 3 are arranged in a T shape. At this time, the installation is located at the stern of the crane ship 1, and the crane ship 1 can lift the single pile 4 through the crane 2, avoiding the risk of connecting the sling when the two ships are directly arranged in a T shape. Connecting the main sling 6 and the auxiliary sling 7 on the single pile 4 on one side of the ship's side is safer.

[0053] S6: Release the binding and reinforcement between the single pile 4 and the transport ship, and the safety pin 73 inserted on the pile turning pliers 71. Lift the single pile 4 by the method of fixed crane 2 rotating angle stern lifting. The crane 2 slowly raises the main hook 21 so that the main sling 6 and the auxiliary sling 7 are gradually stressed. The main sling 6, the auxiliary sling 7 and the axis of the single pile 4 form an obtuse triangle, so that the angle α between the axis of the single pile 4 and the horizontal after lifting is between 8 and 16 degrees, which is convenient for the movement of the transport ship 3. After the single pile 4 is separated from the transport ship 3, the transport ship 3 leaves the berth using the natural water flow.

[0054] S7: The single pile 4 is turned over in the water to the vertical state. The main hook 21 of the crane 2 slowly descends. The single pile 4 is gradually immersed in the water until the bottom of the pile touches the mud, and then the auxiliary sling 7 becomes slack and is not stressed. The auxiliary hook 22 of the crane 2 slowly rises, driving the swivel shackle 72 to make the auxiliary sling 7 disengage from the hook teeth of the main hook 21. The main hook 21 of the crane 2 slowly rises, and the single pile 4 is gradually turned over to the vertical state. During the process, the pile bottom turning pliers 71 automatically disengages from the bottom of the pile under the action of gravity. The small hook 23 of the crane 2 rises to recover the auxiliary sling 7 with the turning pliers 71.

[0055] S8: The crane ship 1 hauls the anchor and moves the ship closer to the pile stabilizing platform 5. Through the cooperation of the windlass to haul the anchor, control the movement of the pile, and feed the pile into the arm dragon mouth of the pile stabilizing platform 5. Close the two-layer annular arms and lock the arm locks.

[0056] S9: Adjust the verticality of the single pile 4, complete the self-weight sinking into the mud, and extend the upper and lower arms. The pile stabilizing platform of the present invention is provided with an upper arm 511 and a lower arm 512. A jack for driving the movement of the arm is arranged behind each group of arms. The jack drives the lower arm 512 to surround the single pile 4 so that the single pile 4 is located at the center position of the arm. Judge the inclination direction according to the verticality data of the single pile 4 measured, and adjust the telescopic distance of the hydraulic jack of the upper arm to adjust the verticality of the single pile 4. In this way, the maximum lifting weight of the crane ship can be exerted, and the hoisting of an ultra-large single pile can be realized.

[0057] The main hook 21 of the crane 2 descends slowly, and the single pile 4 sinks into the mud under its own weight. During this period, the verticality is measured repeatedly for many times and adjusted by the above method.

[0058] S10: Adjust the left rear anchor of the crane barge 1 and adjust the position of the crane barge 1 to make the pile stabilizing platform 5 located on the side of the crane barge 1, which is beneficial to the hydraulic hammer pile driving operation.

[0059] S11: Lift the hydraulic hammer and drive the single pile 4 to the design elevation.

[0060] Obviously, the above-mentioned embodiments of the present invention are only examples for clearly explaining the present invention, rather than limiting the implementation manners of the present invention. For those of ordinary skill in the art, various obvious changes, re-adjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. A construction method for a super-large single pile in the sea, characterized in that, It includes the following steps: S1. The crane ship (1) sails to a preset position and deploys positioning anchors for positioning; S2. Use the crane ship (1) to install the pile stabilizing platform (5). After the crane ship (1) hoists the pile stabilizing platform (5) and completes the in-position operation, according to the data real-time feedback by the high-precision GPS positioning equipment on the pile stabilizing platform (5), adjust the planar position and orientation of the pile stabilizing platform (5) through the crane, so that the pile stabilizing platform (5) is installed at the set position on the stern side of the crane ship, with the center of the holding arm coinciding with the center of the machine position, and open the upper holding arm (511) and the lower holding arm (512) on the pile stabilizing platform; S3. Berth the transport ship (3) which has a monopile (4) placed on it parallel to the side of the crane ship (1) so that the bottom of the monopile (4) faces the bow of the crane ship (1); S4. Hang one end of the main lifting cable (6) on the hook teeth of the main hook (21) of the crane (2), and hang the auxiliary lifting cable (7) on another hook tooth of the main hook (21). Connect the middle of the auxiliary lifting cable (7) to a shackle and hang it on the small hook (23); The auxiliary hook (22) is connected to the shackle (72) of the auxiliary lifting cable (7) for assisting the auxiliary lifting cable (7) to unhook. The crane (2) rotates to above the bottom of the monopile (4), and use the small hook (23) to install the pile turning tongs (71) on the upper side of the bottom of the monopile (4), and use the safety pin (73) to fix the pile turning tongs (71) to the lug preset on the outer wall of the pile bottom; The crane (2) rotates to above the lifting lug of the monopile (4) and hang the main lifting cable (6) on the lifting lug of the monopile (4); S5. Slowly transfer the transport ship (3) to the stern. There is a cable (9) connecting the crane ship (1) and the transport ship (3). Use the rotation of the crane (2) to drive the transport ship under the monopile (4) to move slowly; The cable winch can take in and pay out the cable (9) to adjust the tightness state and control the stability of the transport ship during the rotation process; S6. Release the fixing of the monopile (4) on the transport ship and the safety pin (73) on the pile turning tongs (71). The crane (2) raises the main hook (21) to gradually apply force to the main lifting cable (6) and the auxiliary lifting cable (7); After the monopile (4) is lifted off the transport ship, the transport ship (3) departs from the berth; S7. The main hook (21) descends, and the monopile (4) is gradually immersed in water until the bottom of the pile touches the mud. Then the auxiliary lifting cable (7) becomes slack and is not under force. The auxiliary hook (22) is lifted to drive the shackle (72) to make the auxiliary lifting cable (7) disengage from the hook teeth of the main hook (21); The main hook (21) continues to rise, and the monopile (4) is flipped to a vertical state, where the pile turning tongs (71) automatically disengages from the bottom of the pile under the action of gravity; The small hook (23) is lifted to recover the auxiliary lifting cable (7) and the pile turning tongs (71) at its end; S8. The crane ship (1) hauls the anchor closer to the pile stabilizing platform and places the monopile (4) within the holding arms of the pile stabilizing platform; S9. Make the monopile (4) perpendicular to the horizontal plane and let it sink into the mud by its own weight. Close the lower holding arm (512) to hold the outer wall of the monopile (4). Judge the inclination direction according to the measured verticality data of the monopile (4), and adjust the telescopic distance of the hydraulic jack on the upper holding arm (511) to adjust the verticality of the monopile (4); The main hook (21) descends to let the monopile (4) sink into the mud by its own weight; S10. Adjust the position of the crane vessel (1) so that the pile stabilizing platform is located on the side, facilitating the operation of the hydraulic hammer. S11. Lift the hydraulic hammer to drive the single pile (4) to the design elevation.

2. The construction method for a super-large single pile in the sea according to claim 1, characterized in that, The step S6 further includes that after the single pile (4) is lifted, the main hoisting cable (6), the auxiliary hoisting cable (7) and the axis of the single pile (4) form an obtuse triangle, and the included angle α between the pile axis and the horizontal plane is between 8° and 16°.

3. The construction method for a super-large single pile in the sea according to claim 1, characterized in that, The step S4 further includes adding a packing block (10) or a tooling at the tail of the transport ship (3).

4. The construction method for a super-large single pile in the sea according to claim 1, characterized in that, The main hook (21), the auxiliary hook (22) and the small hook (23) are arranged in a straight line, and the main hook (21) is a cross-shaped four-claw lifting hook.

5. The construction method for a super-large single pile in the sea according to claim 1, characterized in that, The pile stabilizing platform (5) is seated on the seabed mud surface. The upper holding arm (511) and the lower holding arm (512) are annular. 4 sets of hydraulic jacks are evenly distributed on the upper holding arm (511) and the lower holding arm (512) respectively. A high-precision GPS positioning device is provided on the pile stabilizing platform (5), and the GPS positioning device displays the planar position and direction of the pile stabilizing platform (5) on the computer in real time.

6. The construction method for a super-large single pile in the sea according to claim 1, characterized in that, The auxiliary hoisting cable (7) can be changed. The hoisting cable steel wire rope of the auxiliary hoisting cable (7) is sectional, and the middle of the hoisting cable steel wire rope is connected with a shackle.

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