Offshore wind power single pile foundation cage breakage and falling repair method

Abstract

The invention discloses an offshore wind power single pile foundation cage breakage and falling repair method. The method comprises the following steps that construction materials and constructors are conveyed to a damaged machine position through a traffic ship; a plurality of electric hoists are installed at the position of a bracket layer bearing ring beam of the cage according to the stress analysis condition during hoisting of the cage with the broken and falling lower portion, and an underwater diver and constructors on the upper portion of the cage are matched to complete hanging of a sling of the cage with the broken and falling lower portion; a constructor on the upper portion of the sleeve cage starts a plurality of electric hoists to hoist the sleeve cage with the broken lower portion and falling off; after the sleeve cage with the broken and falling lower part is hoisted and aligned, the broken part is repaired, welded and reinforced; and carrying out anti-corrosion coating on the repaired part. According to the method, existing traffic tools and simple equipment in the current market are utilized, an underwater-overwater two-way cooperative working mode is adopted, a crane ship is not needed, a wind turbine generator assembly does not need to be dismantled, repairing of broken and falling of the cage can be completed, and the construction difficulty and cost are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of offshore wind power, and in particular to a method for repairing a broken and fallen cage of an offshore wind power single pile foundation. Background Art

[0002] At present, offshore wind power technology is developing rapidly, especially with the increasing installed capacity in offshore areas, more and more wind turbines have been put into operation. Among them, the monopile foundation, as the simplest and most practical structural form, is widely used by various units. In the monopile foundation, the monopile cage accessory components are the main structures for the berthing of the operation and maintenance ship and the personnel to get on and off the wind turbine, and play a vital role in the operation and maintenance of the wind turbine. During the berthing of the operation and maintenance ship, the cage components will cause continuous strong impact. With the increase in the number of berthing times, coupled with the influence of corrosion in the harsh marine environment, the cage components will gradually crack, and even break and fall, resulting in a decrease in the service life of the cage components and an increase in the operation and maintenance risk of the wind turbine. If a crane ship is used for construction and repair, since the wind turbine has been installed and put into operation, the construction difficulty of the crane ship is relatively large and the repair risk is high. If the damaged cage is removed and the cage structure is redesigned, the construction cost is relatively high. Therefore, there is no good way to solve the problem of cage component breakage and falling. How to repair the cage components on the premise that the wind turbine has been put into operation and the wind turbine components are not removed has become an urgent problem to be solved in the field of offshore wind power technology. Summary of the invention

[0003] In order to overcome the shortcomings of the prior art, the purpose of the present invention is to provide a method for repairing a broken and fallen cage of an offshore wind power monopile foundation, which can repair the cage components without dismantling the wind turbine assembly after the wind turbine has been put into operation, thereby reducing construction difficulty and cost.

[0004] In order to solve the above problems, the technical solution adopted by the present invention is as follows: A method for repairing the broken and fallen cage of an offshore wind power monopile foundation comprises the following steps:

[0005] Step S100: transporting construction materials and construction personnel to the damaged machine position by means of a transport vessel;

[0006] Step S200: at the load-bearing ring beam of the cage's corbel layer, multiple electric hoists are installed according to the force analysis when the lower broken and fallen cage is lifted, and underwater divers cooperate with the cage upper construction personnel to complete the installation of the lifting slings of the lower broken and fallen cage;

[0007] Step S300: Construction workers on the upper part of the cage start multiple electric hoists to lift the broken and fallen cage at the lower part;

[0008] Step S400, after the broken and fallen cage at the lower part is lifted and aligned, the broken part is repaired and welded for reinforcement;

[0009] Step S500, applying anti-corrosion coating to the repaired part;

[0010] Step S600: clean up on-site tools and evacuate the fan.

[0011] Compared with the prior art, the present invention has the following beneficial effects:

[0012] 1. Use the existing transport boats as transportation to transport construction materials and construction personnel, and then use the electric hoists and slings commonly available on the market as the main lifting tools for the broken and fallen cage at the bottom, which effectively utilizes the existing equipment on the market and greatly reduces the cost of developing new equipment and new tools;

[0013] 2. The lifting method of multiple sets of electric hoists + slings can realize the load distribution at multiple lifting points. No lifting ship is required, and only manual operation is required. The operation is convenient and simple, the cost is low, and the safety is high. The electric hoist can be controlled at a single point to improve the control accuracy and construction efficiency. At the same time, it is also convenient for construction personnel to remotely control the electric hoist to lift the broken and dropped cage at the bottom, which effectively ensures the personal safety of construction personnel and improves the safety of construction;

[0014] 3. Through the cooperation of underwater divers and construction workers on the upper part of the cage to hang the slings, the two-way coordination of "underwater-above water" is realized. It can be carried out at multiple points at the same time, the process is simple, and the construction efficiency is greatly improved;

[0015] 4. This method utilizes the existing means of transportation and simple equipment on the market, and adopts an "underwater-above water" two-way collaborative working mode. It does not require a crane ship or the removal of wind turbine components to complete the repair of a broken and fallen cage, reducing the construction difficulty and cost without affecting the normal use of the wind turbine.

[0016] In the above-mentioned offshore wind power single pile foundation cage fracture and fall repair method, in step S100, the transportation ship adopts the top flow operation method, and the transportation ship maintains a continuous moving vehicle state, and the cable is brought from the bow cable pile of the transportation ship to the connection between the cage second-layer ring beam and the supporting column.

[0017] The above-mentioned offshore wind power monopile foundation cage fracture and fall repair method, step S200 includes the following steps:

[0018] Step S210, calculating the weight of the cage that has broken and fallen from the lower part, and analyzing and obtaining the arrangement positions of multiple electric hoists at the load-bearing ring beam of the corbel layer;

[0019] Step S220, according to the arrangement positions of the multiple electric hoists obtained in step S210, hang the upper sling at the corresponding position of the load-bearing ring beam of the corbel layer, and hang the electric hoist at the lower joint of the upper sling;

[0020] Step S230: Through the cooperation of underwater divers and cage upper construction personnel, the upper joint of the lower sling is hung on the hook at the bottom of the electric hoist, and the lower joint of the lower sling is hung to the third-layer ring beam of the broken and fallen cage.

[0021] The above-mentioned offshore wind power monopile foundation cage fracture and fall repair method, step S300 includes the following steps:

[0022] Step S310, lifting the broken and fallen cage out of the water;

[0023] Step S320, hoist the broken and fallen cage at the lower part to a predetermined height, and perform inspection and preparation work before welding repair;

[0024] Step S330, continue to lift the broken and dropped cage at the lower part until the alignment is completed.

[0025] In the above-mentioned offshore wind power monopile foundation cage fracture and fall repair method, in step S310,

[0026] If the lower broken falling cage is not tilted, directly lift the lower broken falling cage horizontally until the lower broken falling cage is completely exposed to the water surface;

[0027] If the lower broken falling cage is tilted, according to the tilt of the lower broken falling cage, all the electric hoists at the high tilt position of the lower broken falling cage will be tightened, and the electric hoists at the low tilt position will be started to pull upward until the entire ring beam is in a horizontal state, and then continue to lift horizontally until the lower broken falling cage is completely exposed to the water surface.

[0028] The above-mentioned offshore wind power monopile foundation cage fracture and fall repair method, step S320 includes the following steps:

[0029] Step S321, after hoisting the broken and fallen cage out of the water to a height that can be used by construction workers, inspect the broken and fallen cage and repair damaged parts;

[0030] Step S322: After the lower broken and fallen cage is further hoisted to a suitable height, preparation work is performed on the lower broken and fallen cage before welding repair.

[0031] The above-mentioned offshore wind power monopile foundation cage fracture and fall repair method, step S330 includes the following steps:

[0032] Step S331, continue to hoist the broken and fallen cage at the bottom to the alignment height;

[0033] Step S332, align the lower broken and dropped cage. During the alignment, it is necessary to observe whether the alignment position of the three-layer ring beam column is deviated. If there is a deviation, the lower broken and dropped cage needs to be rotated to adjust the angle.

[0034] In the above-mentioned offshore wind power monopile foundation cage fracture and fall repair method, in step S332, the accuracy of the alignment of the lower fractured and fallen cage can be controlled by any of the following methods:

[0035] Method 1: Connect a traction rope between a supporting column of the upper cage and a supporting column of the lower broken and fallen cage, and connect a hand chain hoist to one end of the traction rope. The on-site operator drags the hand chain hoist to rotate and align the lower broken and fallen cage;

[0036] Method 2: Pull the guy rope on the transportation ship to the supporting column of the lower broken and fallen cage, and slowly drag the lower broken and fallen cage by the transportation ship to rotate and align;

[0037] Method three: At the joint between the supporting column and the ring beam, weld an alignment plug on the ring beam as an auxiliary structure to fix the position and assist the lower part to break and fall into the cage alignment.

[0038] The above-mentioned offshore wind power monopile foundation cage fracture and fall repair method, step S400 includes the following steps:

[0039] Step S410, welding port position processing;

[0040] Step S420, welding the supporting column and the ring beam;

[0041] Step S430: perform weld flaw detection.

[0042] The above-mentioned offshore wind power monopile foundation cage fracture and fall repair method, step S500 includes the following steps:

[0043] Step S510, grinding the metal surface of the repaired part;

[0044] Step S520: After the polishing is completed, the transition position between the paint and the steel plate is polished gently, and then the repaired part is cleaned and painted by applying the primer first and then the topcoat;

[0045] Step S530: After painting is completed, the paint film thickness is checked.

[0046] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 Schematic diagram of the overall structure of the cage;

[0048] Figure 2 This is a schematic diagram of the lower ring beam of the cage falling;

[0049] Figure 3 It is a flow chart of a method for repairing a broken cage falling off according to an embodiment of the present invention;

[0050] Figure 4 This is a schematic diagram of the wind turbine foundation for a transport ship berthing;

[0051] Figure 5 This is a schematic diagram of the installation position of the electric hoist;

[0052] Figure 6 This is a schematic diagram of the hoisting;

[0053] Figure 7 This is a schematic diagram of the welding alignment tip position. DETAILED DESCRIPTION

[0054] Reference Figure 1 The cage generally includes supporting columns, a first-layer ring beam, a second-layer ring beam, a third-layer ring beam and a fourth-layer ring beam, among which the first-layer ring beam is also the corbel layer load-bearing ring beam. During the berthing period, the maintenance ship will cause continuous strong impact on the cage components. With the increase in the number of berthing times, coupled with the influence of corrosion in the harsh marine environment, the cage components will gradually crack or even break and fall off. For example, Figure 2 As shown, the lower ring beam of the cage is broken and falls off. Therefore, the broken and fallen cage needs to be repaired.

[0055] In order to repair the cage components without dismantling the wind turbine components after the wind turbine has been put into operation, the construction difficulty and cost can be reduced. Figure 3 The embodiment of the present invention provides a method for repairing a broken and fallen cage of an offshore wind power monopile foundation, comprising the following steps:

[0056] Step S100: transporting construction materials and construction personnel to the damaged machine position by means of a transport vessel;

[0057] Step S200: at the load-bearing ring beam of the cage's corbel layer, multiple electric hoists are installed according to the force analysis when the lower broken and fallen cage is lifted, and underwater divers cooperate with the cage upper construction personnel to complete the installation of the lifting slings of the lower broken and fallen cage;

[0058] Step S300: Construction workers on the upper part of the cage start multiple electric hoists to lift the broken and fallen cage at the lower part;

[0059] Step S400, after the broken and fallen cage at the lower part is lifted and aligned, the broken part is repaired and welded for reinforcement;

[0060] Step S500, applying anti-corrosion coating to the repaired part;

[0061] Step S600: clean up on-site tools and evacuate the fan.

[0062] The beneficial effects of the present invention are:

[0063] 1. Use the existing transport boats as transportation to transport construction materials and construction personnel, and then use the electric hoists and slings commonly available on the market as the main lifting tools for the broken and fallen cage at the bottom, which effectively utilizes the existing equipment on the market and greatly reduces the cost of developing new equipment and new tools;

[0064] 2. The lifting method of multiple sets of electric hoists + slings can realize the load distribution at multiple lifting points. No lifting ship is required, and only manual operation is required. The operation is convenient and simple, the cost is low, and the safety is high. The electric hoist can be controlled at a single point to improve the control accuracy and construction efficiency. At the same time, it is also convenient for construction personnel to remotely control the electric hoist to lift the broken and dropped cage at the bottom, which effectively ensures the personal safety of construction personnel and improves the safety of construction;

[0065] 3. Through the cooperation of underwater divers and construction workers on the upper part of the cage to hang the slings, the two-way coordination of "underwater-above water" is realized. It can be carried out at multiple points at the same time, the process is simple, and the construction efficiency is greatly improved;

[0066] 4. This method utilizes the existing means of transportation and simple equipment on the market, and adopts an "underwater-above water" two-way collaborative working mode. It does not require a crane ship or the removal of wind turbine components to complete the repair of a broken and fallen cage, reducing the construction difficulty and cost without affecting the normal use of the wind turbine.

[0067] Furthermore, in step S100, the construction materials and construction personnel are transported to the damaged position by a transport ship, and the construction materials are transferred to the wind turbine as well as the personnel are transferred to the wind turbine. Figure 4 , the transport ship adopts the top-current operation method to reduce the roll of the transport ship during the operation. The transport ship maintains a continuous moving state, relying on the engine to provide continuous power to the transport ship to stabilize the ship forward and backward, ensuring that the transport ship does not drift at will and is always in a controllable state. From the bow cable pile of the transport ship to the connection between the second-layer ring beam of the cage and the supporting column, the transport ship cable is pulled out by the transport ship cable pile and connected to the connection point between the second-layer ring beam of the cage and the supporting column as an auxiliary measure to stabilize the ship. By carrying out the above three measures at the same time, it can be ensured that the transport ship is docked near the machine position and the ship position remains unchanged during construction. In addition, the transport ship can not only realize the transportation of equipment and materials and the pick-up and drop-off of construction personnel, but also provide power for on-site construction, and use the transport ship cable on the transport ship to lead to the lower broken cage to assist in alignment. No large ships and additional equipment are required to assist in construction, which further reduces the difficulty of construction.

[0068] After completing step S100, the electric hoist and the sling are installed, that is, step S200 is implemented. Further, in step S200, 10 10t electric hoists are installed at the load-bearing ring beam of the cage member at the corbel layer according to the force distribution when the cage is hoisted, and the circuit connection of the electric hoist is completed.

[0069] Step S200 specifically includes the following steps:

[0070] Step S210, calculate the weight of the cage that has broken and fallen from the bottom, and analyze and obtain the arrangement positions of 10 electric hoists at the load-bearing ring beam of the corbel layer. The arrangement positions are as follows: Figure 5 As shown;

[0071] Step S220, according to the arrangement positions of the multiple electric hoists obtained in step S210, hang the upper sling at the corresponding position of the load-bearing ring beam of the corbel layer, and hang the electric hoist at the lower joint of the upper sling;

[0072] Step S230: Through the cooperation of the underwater diver and the cage upper construction personnel, the upper joint of the lower sling is hung on the hook at the bottom of the electric hoist, and the lower joint of the lower sling is hung to the third ring beam of the lower broken cage. The upper sling and the lower sling are the slings mentioned in the above step S200. The structure after the electric hoist is installed and the slings are hung is as follows: Figure 6 shown.

[0073] Furthermore, after the installation of the slings for the broken and fallen cage at the bottom is completed, the on-site commander can instruct the construction personnel at the top of the cage to start the electric hoist to lift the cage after checking that everything is correct. That is, step S300 is implemented, and step S300 specifically includes the following steps:

[0074] Step S310, lifting the broken and fallen cage out of the water;

[0075] Step S320, hoist the broken and fallen cage at the lower part to a predetermined height, and perform inspection and preparation work before welding repair;

[0076] Step S330, continue to lift the broken and dropped cage at the lower part until the alignment is completed.

[0077] Among them, in step S310, it is necessary to observe the horizontality of the cage during lifting and make real-time adjustments to ensure that the cage remains lifted horizontally. Specifically, if the lower broken and falling cage is not tilted, the lower broken and falling cage is directly lifted horizontally until the lower broken and falling cage is completely exposed to the water surface; if the lower broken and falling cage is tilted, then according to the tilt of the lower broken and falling cage, all the electric hoists at the high tilt position of the lower broken and falling cage are tightened, and the electric hoists at the low tilt position are started to pull upward until the entire ring beam is in a horizontal state, and then the horizontal lifting is continued until the lower broken and falling cage is completely exposed to the water surface.

[0078] Further, step S320 includes the following steps:

[0079] Step S321, after the broken and fallen cage at the lower part is hoisted out of the water to a height at which construction workers can work, the broken and fallen cage at the lower part is inspected, and damaged parts such as cage ladders, support columns, etc. are repaired;

[0080] Step S322, after the lower broken and fallen cage is further hoisted to a suitable height, the preparation work before welding repair is performed on the lower broken and fallen cage, including adding panels to the welding joints of the ring beam, gouging the broken joints, preparing grooves at the welding joints, correcting the alignment, etc.

[0081] Further, step S330 includes the following steps:

[0082] Step S331, continue to hoist the broken and fallen cage at the bottom to the alignment height;

[0083] Step S332, align the lower broken and dropped cage. During alignment, it is necessary to observe whether the alignment position of the three-layer ring beam column is deviated. If there is a deviation, the lower broken and dropped cage needs to be rotated to adjust the angle. Specifically, the accuracy of the lower broken and dropped cage alignment can be controlled by any of the following methods:

[0084] Method 1: Connect a traction rope between a supporting column of the upper cage and a supporting column of the lower broken and fallen cage, and connect a hand chain hoist to one end of the traction rope. The on-site operator drags the hand chain hoist to rotate and align the lower broken and fallen cage;

[0085] Method 2: Pull the guy rope on the transportation ship to the supporting column of the lower broken and fallen cage, and slowly drag the lower broken and fallen cage by the transportation ship to rotate and align;

[0086] Method 3: Figure 7 As shown, at the joint position between the supporting column and the ring beam, an alignment plug tip is welded on the ring beam as an auxiliary structure to fix the position and assist the lower part to break and fall off the cage.

[0087] After the cage is aligned, welding reinforcement is performed, that is, step S400 is implemented. Specifically, step S400 includes the following steps:

[0088] Step S410, welding port position processing;

[0089] Step S420, welding the supporting column and the ring beam;

[0090] Step S430: perform weld flaw detection.

[0091] Specifically, in step S410, the position of the fracture between the ring beam and the supporting column is air-planed and polished, and a welding groove is processed. A new steel plate is added and welded as a welding reinforcement plate, and the supporting column is welded to the new steel plate after the subsequent alignment is completed. The fracture surface of the supporting column is air-planed, and a suitable groove is trimmed for subsequent welding. In step S420, after all the supporting columns are positioned, welding work can be carried out. After the welding of the supporting columns is completed, reinforcement structures such as welded stiffening plates can be added. After welding is completed, each structural weld needs to be inspected for weld flaws, and all positions of the cage repair welding should be subjected to 100% UT and MT non-destructive testing, with an acceptance level of Level I. Weld flaw detection specifically includes the following steps:

[0092] a. The connection welds between the ring beam and the supporting columns shall be subjected to 100% UT and MT nondestructive testing, with the acceptance level being Level I;

[0093] b. The welds of other auxiliary components should be subjected to 100% UT inspection with acceptance level I, or replaced by radiographic inspection of the same level.

[0094] After the weld flaw detection is completed, the cage anti-corrosion repair needs to be performed, that is, step S500 is implemented. Specifically, step S500 includes the following steps:

[0095] Step S510, grinding the metal surface of the repaired part;

[0096] Step S520: After the polishing is completed, the transition position between the paint and the steel plate is polished gently, and then the repaired part is cleaned and painted by applying the primer first and then the topcoat;

[0097] Step S530: After painting is completed, the paint film thickness is checked.

[0098] Among them, in step S510, the metal surface of the repaired part is polished to St3 level with a power tool, and the surface of the exposed part of the base material should have a metallic luster. In step S520, sandpaper is used to polish the transition position between the paint and the steel plate, and then the part to be repaired is cleaned with a clean dry cloth, and then anti-corrosion coating is performed. After the coating is completed, the paint film thickness is checked to ensure that the paint thickness meets the requirements. After the anti-corrosion coating is completed, all tools on site are cleaned and the fan is evacuated.

[0099] It should be noted that in the description of the present invention, if there are any orientation descriptions, such as up, down, front, back, left, right, etc., the orientations or positional relationships indicated are all based on the orientations or positional relationships shown in the drawings. They 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, be constructed or operated in a specific orientation, and cannot be understood as a limitation on the present invention.

[0100] In the description of the present invention, "several" means one or more, "more" means two or more, "greater than", "less than", "exceed" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used to distinguish the technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0101] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0102] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A method for repairing a broken and fallen cage of an offshore wind power monopile foundation, characterized in that: The steps include: Step S100: transporting construction materials and construction personnel to the damaged machine position by means of a transport vessel; Step S200: at the load-bearing ring beam of the cage's corbel layer, multiple electric hoists are installed according to the force analysis when the lower broken and fallen cage is lifted, and underwater divers cooperate with the cage upper construction personnel to complete the installation of the lifting slings of the lower broken and fallen cage; Step S300: Construction workers on the upper part of the cage start multiple electric hoists to lift the broken and fallen cage at the lower part; Step S400, after the broken and fallen cage at the lower part is lifted and aligned, the broken part is repaired and welded for reinforcement; Step S500, applying anti-corrosion coating to the repaired part; Step S600: clean up on-site tools and evacuate the fan.

2. The method for repairing the broken and fallen cage of the offshore wind power monopile foundation according to claim 1 is characterized in that: In step S100, the transport ship adopts the top-current operation method, and the transport ship maintains a continuous moving vehicle state, and the cable is brought from the bow mooring pile of the transport ship to the connection between the second-layer ring beam of the cage and the supporting column.

3. The method for repairing the broken and fallen cage of the offshore wind power monopile foundation according to claim 1 is characterized in that: Step S200 includes the following steps: Step S210, calculating the weight of the cage that has broken and fallen from the lower part, and analyzing and obtaining the arrangement positions of multiple electric hoists at the load-bearing ring beam of the corbel layer; Step S220, according to the arrangement positions of the multiple electric hoists obtained in step S210, hang the upper sling at the corresponding position of the load-bearing ring beam of the corbel layer, and hang the electric hoist at the lower joint of the upper sling; Step S230: Through the cooperation of underwater divers and cage upper construction personnel, the upper joint of the lower sling is hung on the hook at the bottom of the electric hoist, and the lower joint of the lower sling is hung to the third-layer ring beam of the broken and fallen cage.

4. The method for repairing the broken and fallen cage of the offshore wind power monopile foundation according to claim 1 is characterized in that: Step S300 includes the following steps: Step S310, lifting the broken and fallen cage out of the water; Step S320, hoist the broken and fallen cage at the lower part to a predetermined height, and perform inspection and preparation work before welding repair; Step S330, continue to lift the broken and dropped cage at the lower part until the alignment is completed.

5. The method for repairing the broken and fallen cage of the offshore wind power monopile foundation according to claim 4 is characterized in that: In step S310, If the lower broken falling cage is not tilted, directly lift the lower broken falling cage horizontally until the lower broken falling cage is completely exposed to the water surface; If the lower broken falling cage is tilted, according to the tilt of the lower broken falling cage, all the electric hoists at the high tilt position of the lower broken falling cage will be tightened, and the electric hoists at the low tilt position will be started to pull upward until the entire ring beam is in a horizontal state, and then continue to lift horizontally until the lower broken falling cage is completely exposed to the water surface.

6. The method for repairing the broken and fallen cage of the offshore wind power monopile foundation according to claim 5 is characterized in that: Step S320 includes the following steps: Step S321, after hoisting the broken and fallen cage out of the water to a height that can be used by construction workers, inspect the broken and fallen cage and repair damaged parts; Step S322: After the lower broken and fallen cage is further hoisted to a suitable height, preparation work is performed on the lower broken and fallen cage before welding repair.

7. The method for repairing the broken and fallen cage of the offshore wind power monopile foundation according to claim 5 is characterized in that: Step S330 includes the following steps: Step S331, continue to hoist the broken and fallen cage at the bottom to the alignment height; Step S332, align the lower broken and dropped cage. During the alignment, it is necessary to observe whether the alignment position of the three-layer ring beam column is deviated. If there is a deviation, the lower broken and dropped cage needs to be rotated to adjust the angle.

8. The method for repairing the broken and fallen cage of the offshore wind power monopile foundation according to claim 7 is characterized in that: In step S332, the accuracy of the lower broken and dropped cage alignment can be controlled by any of the following methods: Method 1: Connect a traction rope between a supporting column of the upper cage and a supporting column of the lower broken and fallen cage, and connect a hand chain hoist to one end of the traction rope. The on-site operator drags the hand chain hoist to rotate and align the lower broken and fallen cage; Method 2: Pull the guy rope on the transportation ship to the supporting column of the lower broken and fallen cage, and slowly drag the lower broken and fallen cage by the transportation ship to rotate and align; Method three: At the joint between the supporting column and the ring beam, weld an alignment plug on the ring beam as an auxiliary structure to fix the position and assist the lower part to break and fall into the cage alignment.

9. The method for repairing the broken and fallen cage of the offshore wind power monopile foundation according to claim 1 is characterized in that: Step S400 includes the following steps: Step S410, welding port position processing; Step S420, welding the supporting column and the ring beam; Step S430: perform weld flaw detection.

10. The method for repairing the broken and fallen cage of the offshore wind power monopile foundation according to claim 1, characterized in that: Step S500 includes the following steps: Step S510, grinding the metal surface of the repaired part; Step S520: After the polishing is completed, the transition position between the paint and the steel plate is polished gently, and then the repaired part is cleaned and painted by applying the primer first and then the topcoat; Step S530: After painting is completed, the paint film thickness is checked.

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