Rapid environment-friendly dismantling method for existing caisson

Abstract

The invention discloses a rapid and environment-friendly dismantling method for an existing caisson, and relates to the technical field of caisson dismantling, the rapid and environment-friendly dismantling method comprises the following steps: S1, an early-stage preparation stage; s11, a breast wall breaking stage; s12, a sludge, accropode and block stone cleaning stage; s2, a stage of digging out the backfill in the box chamber in an ear-digging manner; s3, a fishing operation stage; and S4, in the stage of mechanically dismantling the caisson and discarding the muck, a hoisting tool for dismantling the caisson of the crane ship and a hoisting hole rapid plug pin deepening technology are used, and through fine design and optimization, the hoisting process is more stable and rapid, and the construction period is greatly shortened. Compared with traditional blasting, mechanical crushing and other methods, the technology has the advantages that noise and vibration in the construction process are reduced, damage to the surrounding environment is reduced, waste generated by dismantling is classified, treated and recycled, and pollution to the environment and waste of resources are reduced.

Description

Technical Field

[0001] This application relates to the technical field of caisson demolition construction. More specifically, this application relates to a method for quickly and environmentally friendly demolishing existing caissons. Background Art

[0002] A caisson is a type of deep foundation, which is a box-shaped structure with a bottom. Partition boards are arranged inside, and it can float in water. By adjusting the ballast water in the box, the caisson can be controlled to sink or float. During construction, sand or rubble is filled in the box, and a cover plate is added on the top to form the main load-bearing and vertical wall structures. With the compressed air input into the working chamber, it prevents groundwater from seeping in, facilitating workers to dig soil indoors, causing the caisson to gradually sink. At the same time, concrete is poured on it. When it sinks to the predetermined depth, the working chamber is filled with concrete to serve as the foundation for heavy structures such as bridge piers and equipment. In the prior art, for the related technologies of caisson construction, reference can be made to the Chinese patent with the publication number CN115949086B, which discloses a method for demolishing an assembled caisson cofferdam. The treatment of the small rabbet between caissons: It is carried out in two steps. First, during the excavation process, the position of the small rabbet waterstop is treated, and after the temporary breast wall is demolished, the small rabbet plastic concrete is treated. Use a down-the-hole hammer to drill holes at the rabbet position between the permanent breast wall and the temporary breast wall to make the small rabbet between the caissons and the rabbets between the permanent breast wall and the temporary breast wall form a continuous section. Use a milling excavator and a flat bucket excavator to demolish the small rabbet waterstop and the small rabbet plastic concrete between the caissons. The treatment of the large rabbet of the caisson: Use a flat bucket excavator to dig out the rubble at the large rabbet between the caissons. Demolish the high-strength threaded steel above the caisson. Excavate the slag inside the caisson compartment. Use a floating crane to hoist and remove the upper structure of the caisson as a whole and place it in a fixed storage area. The construction is highly operable and safe, with low cost investment, high construction efficiency and quality assurance. To sum up, the purpose of this technical solution is to solve the problems of low efficiency, serious environmental pollution and potential safety hazards during the existing caisson demolition process. Currently, common demolition methods include blasting or mechanical crushing. These methods not only have a long construction period, but also generate a large amount of noise, dust and waste, causing significant impact on the surrounding environment. In addition, the high safety risks during the demolition process also pose a threat to the personal safety of construction workers. Therefore, a method for quickly and environmentally friendly demolishing existing caissons is proposed for the above problems. Summary of the Invention

[0003] In order to overcome the above-mentioned defects of the prior art, this application provides a method for quickly and environmentally friendly demolishing existing caissons to solve the problems mentioned in the above background art.

[0004] To achieve the above purpose, this application provides the following technical solution: A method for quickly and environmentally friendly demolishing existing caissons includes the following steps: S1. Preliminary preparation stage; S11. Breast wall demolition stage; S12. Sludge, tetrapods and rubble cleaning stage; S2. Ear-like excavation of backfill in the caisson chamber; S3. Salvage operation stage; S4. Mechanical demolition of the caisson and disposal of muck outside the site.

[0005] Preferably, in step S1, according to the construction drawings and the actual site conditions, determine the lifting position of the crane ship and the layout of the temporary passage, conduct a comprehensive inspection and commissioning of the crane ship, lifting gear and pin construction equipment, and organize divers for technical training and safety disclosure, so that they are familiar with the construction process and safety operation procedures.

[0006] Preferably, in step S11, there is a 40m-long breast wall on the top of the caisson. Use a hydraulic breaker to demolish the breast wall and retaining wall on the top of the caisson, and control the demolition strength and rhythm; During construction, demolish the original upper structure, chisel concrete blocks to fill the equipment standing platform and passage to form a temporary passage. The crusher adopts a reverse construction sequence to gradually break the breast wall in turn. The chiseled breast wall fragments are transported by an excavator to the temporary passage for filling. During the demolition process, set a safety warning line in the operation area, and timely clean up the crushed stones and sundries generated by the demolition to keep the construction site clean.

[0007] Preferably, in step S12, when the caisson foundation bed design adopts a combined scheme of rubble cushion, tetrapods and rubble revetment, use an extended-arm excavator on the temporary standing platform on the top of the caisson to remove the sludge, tetrapods and rubble on both sides of the caisson. The elevation of the sediment and rubble is lower than the bottom slab of the caisson; The operating arm of the excavator controls the entry position and excavation depth of the bucket, and timely transports the removed sludge and rubble to the designated location for treatment.

[0008] Preferably, in step S2, the caisson chamber is backfilled with sand and gravel to reduce its self-weight. Use an extended-arm excavator in cooperation with a hydraulic backhoe to remove the rubble on the top and the backfill sand at the bottom of the caisson chamber, and transport the backfill to the temporary passage. In addition, monitor the caisson structure. Once any abnormality is found, immediately stop the operation and take corresponding remedial measures.

[0009] Preferably, in step S3, the hook of the crane ship lowers the perforated pin steel bar to the lifting hole position. The diver accurately inserts the steel bar into the lifting hole underwater. The other end of the steel bar is successively sleeved with a flange plate and a limit steel bar is inserted. The pin is horizontal in the wall and symmetric at both ends; Pre-lift the caisson, lift one side of the lifting gear. After the bottom of one side of the caisson is lifted off the mud surface, then lift the other side of the lifting gear; The crane ship gradually raises the hook, and the caisson slowly rises to the sea surface. At the same time, the drain holes drain water to reduce the weight. The caisson leaves the water surface, maintaining the stable attitude of the crane ship. Detect the performance of the equipment to confirm that the sling is not deformed or damaged, and whether the wall of the caisson hoisting position is intact without tensile cracks. Place the submersible pump in the caisson chamber and start the pumping and draining operation. The caisson continues to be lifted to 1 meter above the top elevation of the temporary passage, and then pauses again for observation. The crane ship transfers the caisson to the predetermined placement position at a uniform speed through the lateral anchor mooring method. Finally, the crane ship slowly lowers the hook and accurately places the caisson at the predetermined position of the temporary passage.

[0010] Preferably, in step S4, the hydraulic breaker breaks the caisson and clears the crushed slag to the designated disposal site.

[0011] The technical effects and advantages of this application: 1. In the lifting tool for caisson demolition and the deepening technology of the quick insertion pin for the hoisting hole in the crane ship in this technical solution, through fine design and optimization, the hoisting process is more stable and fast, significantly shortening the construction period. Compared with traditional methods such as blasting and mechanical crushing, this technology reduces noise and vibration during construction, also reduces damage to the surrounding environment, classifies and recycles the waste generated during demolition, and reduces environmental pollution and waste of resources. 2. By adopting the quick caisson demolition construction technology, the construction efficiency and environmental protection standards can be improved, the construction quality can be ensured. Through the use of an extended-arm excavator in cooperation with a hydraulic backhoe, the backfill in the caisson chamber can be efficiently excavated, the caisson can be integrally hoisted and transported to the shore, and the caisson can be quickly broken, thus shortening the construction period, saving costs, and significantly reducing interference to the surrounding environment. At the same time, the hydraulic breaker equipment is also used to effectively control the noise and vibration generated during the crushing process at the construction site, reducing the negative impact on surrounding residents and buildings. During the construction process, the construction waste generated is used for backfilling and paving the road, and the crushed slag and garbage are promptly cleaned to keep the construction environment clean and hygienic, reducing the degree of pollution to the surrounding construction environment during the caisson demolition process. 3. By adopting the existing quick and environmentally friendly caisson demolition construction technology and using the construction method of an extended-arm excavator in cooperation with a hydraulic backhoe, the backfill in the caisson chamber can be effectively excavated, and the non-destructive integral salvage operation of the caisson can be achieved. These technologies ensure that even under the condition of limited tide during the demolition operation, the transfer of the caisson to the shore and the crushing work can still be completed within 24 hours, thus improving the construction efficiency. And this process also ensures the thoroughness of the caisson demolition construction, having no impact on the subsequent construction of the breakwater at this location. Construction units with construction period requirements can make choices according to the construction period. Description of the Drawings

[0012] Figure 1 This is a flowchart of a method for quickly and environmentally friendly demolishing existing caissons of the present invention; Figure 2 This is a hoisting construction flowchart of a method for quickly and environmentally friendly demolishing existing caissons of the present invention; Figure 3 This is a schematic diagram showing one side of a caisson being lifted in a method for quickly and environmentally friendly demolishing existing caissons of the present invention; Figure 4 This is a schematic diagram of a caisson being moved and crushed in a method for quickly and environmentally friendly demolishing existing caissons of the present invention; Figure 5 This is a schematic diagram showing the connection between a lifting tool and a caisson in a method for quickly and environmentally friendly demolishing existing caissons of the present invention; Figure 6 This is a schematic diagram of a caisson being hoisted in a method for quickly and environmentally friendly demolishing existing caissons of the present invention.

[0013] Description of the reference numerals in the drawings: 1, crane ship; 2, lifting tool; 3, caisson; 4, perforated plug steel bar; 5, crusher; 6, long-arm excavator. Detailed implementation manners

[0014] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0015] Embodiment 1 As shown in the attached Figures 1 to 6 A method for quickly and environmentally friendly demolishing existing caissons includes the following steps: S1. Preliminary preparation stage; S11. Breast wall demolition stage; S12. Stage of cleaning silt, tetrapods and rubble; S2. Stage of ear-like excavation of the backfill in the caisson chamber; S3. Salvage operation stage; S4. Stage of mechanically demolishing the caisson 3 and disposing of the muck outside; Use a hydraulic breaker to demolish the breast wall and retaining wall on top of the caisson 3. Subsequently, with the help of an extended-arm excavator 6 on the temporary narrow passage formed by backfilling with rubble removed from the old dike, clean the silt and rubble around the caisson 3. At the same time, this excavator can also remove the rubble and sand inside the caisson 3 of the caisson 3. By using the extended-arm excavator 6 in combination with the hydraulic backhoe technology, the problems of insufficient operation accuracy and difficulty in controlling the excavation depth of traditional bucket dredgers in narrow areas are solved. At the same time, in response to the challenge of difficult excavation of backfill materials over the years, use a hydraulic backhoe for excavation operations, and its efficiency has been significantly improved compared with plum blossom grabs and scallop grabs. And by precisely controlling the water entry position of the bucket through the excavator arm, accurate positioning and controllable dredging depth are achieved, so that the silt, rubble around the caisson 3 and the rubble and sand inside the caisson can be quickly cleaned up. At the same time, divers can first dive into the water to search for the position of the lifting holes of the caisson 3.

[0016] After the preliminary preparation work is completed, dispatch the crane ship 1 to prepare for the lifting operation. The crane ship 1 anchors and positions, installs the lifting tackle 2 and the insertion pin steel bar for the lifting hole, and uses the technology of quickly and accurately inserting the insertion pin for the lifting hole of the caisson 3 to achieve the quick and accurate insertion of the insertion pin steel bar for the lifting hole, greatly shortening the time required for the insertion process, reducing the labor intensity and safety risks of divers, further improving the efficiency of the salvage operation of the caisson 3, and lifting the caisson 3 out of the water and transporting it to the top surface of the shore of the temporary passage. Finally, use a hydraulic breaker for rapid crushing, clean up the crushed slag and dispose of it to the designated disposal site.

[0017] Embodiment 2 Based on Embodiment 1, the solution in Embodiment 1 will be further refined and introduced in combination with the following specific working methods, as Figures 1 to 6 shown, and the details are described below: As a preferred implementation method, in step S1, according to the construction drawings and the actual situation on site, determine the lifting position of the crane ship 1 and the layout of the temporary passage, conduct a comprehensive inspection and commissioning of the crane ship 1, the lifting tackle 2, and the insertion pin construction equipment, and organize technical training and safety disclosure for divers to familiarize them with the construction process and safety operation procedures.

[0018] As a preferred implementation method, in step S11, there is a 40m-long breast wall on top of the caisson 3. Use a hydraulic breaker to demolish the breast wall and retaining wall on top of the caisson 3 and control the demolition strength and rhythm; During construction, demolish the original upper structure, chisel the concrete blocks to fill the equipment standing platform and passage to form a temporary passage. The crusher 5 adopts a reverse construction sequence to gradually break the breast wall one by one. The broken pieces of the breast wall are transported by the excavator to the temporary passage for filling. During the demolition process, set a safety warning line in the operation area, and promptly clean up the crushed stones and sundries generated by the demolition to keep the construction site clean and tidy.

[0019] As a preferred embodiment, in step S12, when the caisson 3 foundation bed design adopts a combined scheme of rubble bedding, combined with tetrapods and rubble slope protection, the extended-arm excavator 6 is used to clear the silt, tetrapods and rubble on both sides of the caisson 3 on the temporary standing platform at the top of the caisson 3, and the elevation of the deposited materials and rubble is lower than the bottom plate of the caisson 3; The operating arm of the excavator controls the water entry position and excavation depth of the bucket, and timely transfers the cleared silt and rubble to the designated location for treatment.

[0020] As a preferred embodiment, in step S2, the caisson 3 chamber is backfilled with sand and gravel to reduce its self-weight. The extended-arm excavator 6 is used in combination with a hydraulic backhoe to remove the rubble at the top and the backfill sand at the bottom inside the caisson 3 chamber, and transfer the backfill materials to the temporary passage. In addition, the structure of the caisson 3 is monitored. Once any abnormality is found, the operation is immediately stopped and corresponding remedial measures are taken; In the ear-picking demolition stage, we studied in detail the excavation sequence, excavation depth of the backfill materials and the environmental protection measures during the excavation process. Through calculation and simulation, we determined the optimal excavation strategy to ensure that the caisson can float smoothly. Therefore, according to the construction difficulty, we finally used a long-arm excavator for precise operation. By precisely controlling the operation of the excavator, unnecessary damage to the caisson structure and the lifting hole structure is avoided, making preparations for the subsequent salvage operation; Secondly, in the salvage operation stage, we focused on the selection of the crane ship, the technical parameters of lifting and floating the caisson, and the operation process of shipping it ashore. We cooperated with a professional crane ship team, formulated a detailed salvage plan, and conducted multiple simulation drills to ensure that the caisson can be safely, efficiently and smoothly lifted, floated and shipped ashore during the actual operation.

[0021] Finally, in the mechanical demolition stage, we selected high-efficiency and low-noise crusher equipment, optimized the demolition process, and paid attention to noise control, dust prevention and waste treatment during the demolition process to minimize the impact of the demolition operation on the surrounding environment.

[0022] As a preferred embodiment, in step S3, the hook of the crane ship 1 lowers the perforated pin steel bar 4 to the position of the lifting hole, and the diver accurately inserts the steel bar into the lifting hole underwater. The other end of the steel bar is successively sleeved with a flange plate and a limiting steel bar, and the pin is horizontal in the wall and symmetric at both ends; The caisson 3 is pre-lifted, and one side of the lifting tool 2 is lifted. After the bottom of one side of the caisson 3 is separated from the mud surface, the other side of the lifting tool 2 is lifted; The crane ship 1 gradually raises the hook, and the caisson 3 slowly rises to the sea surface. At the same time, the drain holes drain water to reduce the weight; The caisson 3 leaves the water surface. Keep the stable attitude of the crane ship 1, detect the performance of the equipment, confirm that the lifting tool 2 is not deformed or damaged, and whether the wall at the lifting position of the caisson 3 is intact without tensile cracks; Place the submersible pump in the chamber of caisson 3 and start the pumping operation. Continue to lift caisson 3 to a position 1 meter above the elevation of the top surface of the temporary passage, pause again and observe. The crane barge 1 transfers caisson 3 to the predetermined placement position at a uniform speed through lateral anchoring. Finally, the crane barge 1 slowly lowers the hook and accurately places caisson 3 at the predetermined position of the temporary passage.

[0023] According to the caisson structure design drawings on the market and the underwater exploration by divers, we determine the form and position of the lifting holes, design the required lifting tackle and pins, calculate the stress conditions of the tackle and pins to ensure that they can meet the strength requirements during the lifting process. At the same time, combined with the caisson design drawings, we draw detailed drawings of the lifting tackle to show the structural design of the lifting tackle in detail, ensuring that the pins can be firmly inserted into the lifting holes to avoid falling off or loosening during the lifting process. Through calculation and simulation analysis, we ensure the reliability and safety of the lifting tackle during the lifting process, providing strong technical support for the subsequent salvage operation. In addition, we also consider the convenience and stability of the tackle in actual operation to ensure that the operator can easily and accurately complete the lifting task. According to the positions of the lifting holes marked on the drawings, divers dive into the water to carefully explore the outer wall of caisson 3 to understand the condition of the lifting holes on caisson 3, making preparations for the subsequent overall lifting and salvage operation. Then the divers record the positions, sizes of the lifting holes and whether they are blocked or damaged. If it is found that the lifting holes are blocked, the divers use professional tools to clean them to ensure that the sling pins can pass through unobstructed. At the same time, the divers also need to check whether there are any damages or cracks on the outer wall of caisson 3 and evaluate the stability of its overall structure. Connect the lifting tackle and slings from top to bottom. First, hang the tops of two loop steel wires on the main hook, and connect the steel wires to the lifting tackle with marine shackles at the bottom. There are 4 lifting lugs at the bottom of the lifting tackle. The top of the loop steel wire is connected to the lifting lug through a marine shackle, and the bottom is connected to a Φ135mm perforated pin steel bar. One end of the perforated steel bar is welded with a baffle, and the other end is inserted into the Φ16 pin hole reserved on the pin steel bar. A retaining pin is twisted into the Φ16 pin hole as a wire rope limit and anti - detachment measure. During the construction of the slings in this project, loop steel wires are used to avoid the disadvantages of the splicing method and the wire clip fixing method on the premise of ensuring safety. At the same time, one end of the perforated steel bar is welded with a baffle, and a Φ16 pin hole is reserved on the pin steel bar at the other end, which can realize quick and accurate insertion into the lifting hole pin steel bar, greatly shortening the time required for the pin insertion process, reducing the labor intensity and safety risks of divers. Among them, the baffle welded to one end of the perforated steel bar plays a role in limiting the position, preventing the bolt steel bar from slipping during the hoisting process. At the same time, it also increases the overall strength of the bolt steel bar, making it more durable. The reserved Φ16 bolt hole is for the convenience of inserting the anti-retreat pin to further ensure the stability of the bolt steel bar during the hoisting process; The material of the bolt steel bar is made of high-strength and corrosion-resistant chromium alloy steel, ensuring that the bolt steel bar can still maintain its excellent mechanical properties and corrosion resistance in a harsh underwater environment, which can extend the service life of the bolt steel bar and further guarantee the safety and reliability of the hoisting operation. After confirming that the hoisting hole condition and the structure of the caisson 3 are safe and the crane ship 1 is anchored in place, the diver will cooperate with the hoisting operation team to install the hoisting tackle 2 and the hoisting hole bolt steel bar according to the position of the hoisting hole, and use the improved rapid and accurate pin insertion technology for the hoisting hole of the caisson 3 to accurately insert the hoisting hole bolt steel bar. Then, the crane ship 1 hoists the caisson 3. During the hoisting process, strictly control the hoisting speed and force to ensure that the caisson 3 is hoisted smoothly and slowly and transferred to the top surface of the temporary access shore to prevent damage to the caisson 3 itself or the surrounding environment. During the salvage operation, install a single-sided pin to increase the preloading force of the caisson 3, and through the single-sided pre-lifting, effectively eliminate the adsorption force at the bottom of the caisson 3. Since the adsorption force at the bottom of the caisson 3 is very large, when this adsorption force suddenly disappears, the caisson 3 will have a sudden jump phenomenon, which will directly lead to the risk of the hull becoming unstable and capsizing. By the above method, we can avoid this potential risk caused by the sudden jump phenomenon. And to ensure the construction safety, cooperate with professional safety supervisors on-site for full-process monitoring. Once any abnormal situation occurs, the operation will be immediately suspended and necessary safety measures will be taken.

[0024] As a preferred implementation method, in step S4, the hydraulic breaker breaks the caisson 3 and clears the crushed slag to the designated disposal site.

[0025] During the whole construction process, it is necessary to strictly abide by the safety operation procedures and environmental protection requirements to ensure the construction safety and quality. At the same time, strengthen the on-site management and coordination to ensure the construction progress and efficiency.

[0026] The working process of this application is as follows: First, use a hydraulic breaker to demolish the breast wall and retaining wall on the top of the caisson 3. Subsequently, with the help of an extended-arm excavator 6 on the temporary narrow passage formed by the backfill of the rubble removed from the old dike, clean the silt and rubble around the caisson 3. At the same time, this excavator can also remove the rubble and sand in the chamber of the caisson 3. By adopting the cooperation of the extended-arm excavator 6 and the hydraulic backhoe technology, the problems of insufficient operation accuracy and difficulty in controlling the excavation depth of the traditional bucket dredger in narrow areas are solved. At the same time, in response to the challenge of the long-term difficulty in excavating the backfill material, the excavation operation is carried out by the hydraulic backhoe, and its efficiency has been significantly improved compared with that of the plum blossom grab and scallop grab. And by accurately controlling the water entry position of the bucket by the excavator arm, accurate positioning and controllable dredging depth are achieved, so that the cleaning work of the silt, rubble around the caisson 3 and the rubble and sand in the chamber can be quickly completed. At the same time, divers can first dive into the water to search for the position of the lifting holes of the caisson 3.

[0027] After the preliminary preparation work is completed, dispatch the crane ship 1 to prepare for the lifting operation. The crane ship 1 anchors and positions, installs the lifting tackle 2 and the lifting hole pin steel bar, and uses the technology of quickly and accurately inserting the lifting hole pin of the caisson 3 to achieve the quick and accurate insertion of the lifting hole pin steel bar, greatly shortening the time required for the pin insertion process, reducing the labor intensity and safety risks of divers, further improving the efficiency of the salvage operation of the caisson 3, lifting the caisson 3 out of the water, transporting it to the top surface of the shore of the temporary passage, and finally using a hydraulic breaker for rapid crushing, cleaning the crushed slag and transporting it to the designated disposal site. The above is the working principle of this method for the rapid and environmentally friendly demolition of existing caissons.

Claims

1. A method for rapid and environmentally friendly dismantling of an existing caisson, characterized in that: The following steps are involved: S1, preliminary preparation stage; S11, breast wall demolition stage; S12, the stage of cleaning up silt, twisted blocks and rocks; S2, the stage of removing the backfill material in the box chamber by digging out the ear; S3, salvage operation stage; S4: Mechanical dismantling of the caisson (3) and disposal of the slag.

2. The method for rapid and environmentally friendly dismantling of an existing caisson according to claim 1 is characterized by: In step S1, the lifting position of the crane vessel (1) and the layout of the temporary passage are determined according to the construction drawings and the actual situation on site, and the crane vessel (1), the lifting equipment (2), and the bolt construction equipment are comprehensively inspected and debugged. Divers are also organized to receive technical training and safety briefings to familiarize themselves with the construction process and safety operating procedures.

3. The method for rapid and environmentally friendly dismantling of an existing caisson according to claim 1 is characterized by: In step S11, a 40 m long breast wall is provided on the top of the caisson (3), and a hydraulic breaker is used to demolish the breast wall and retaining wall on the top of the caisson (3), and the demolition force and rhythm are controlled; During the construction, the original upper structure is demolished, and concrete blocks are removed to fill the equipment platform and passage to form a temporary passage. The crusher (5) adopts a reverse construction sequence to gradually break the breast wall. The breast wall fragments removed are transported to the temporary passage by an excavator for filling. During the demolition process, a safety cordon is set up in the work area to promptly clean up the rubble and debris generated by the demolition to keep the construction site clean.

4. The method for rapid and environmentally friendly dismantling of an existing caisson according to claim 1 is characterized by: In step S12, when the base bed design of the caisson (3) adopts a combination of a riprap cushion layer, a twisted king-shaped block and a riprap slope protection, an extended arm excavator (6) is used on a temporary standing platform on the top of the caisson (3) to remove silt, twisted king-shaped blocks and boulders on both sides of the caisson (3), and the elevation of the silt and boulders is lower than the bottom plate of the caisson (3); The excavator's operating arm controls the bucket's entry into the water and the excavation depth, and promptly transports the removed silt and rocks to the designated location for treatment.

5. The method for rapid and environmentally friendly dismantling of an existing caisson according to claim 1 is characterized by: In step S2, the caisson (3) chamber is backfilled with sand and gravel to reduce its own weight, and an extended arm excavator (6) is used in conjunction with a hydraulic backhoe to remove the top rocks and bottom backfill sand in the caisson (3) chamber, and the backfill is transported to a temporary passage. In addition, the caisson (3) structure is monitored, and once an abnormality is found, the operation is immediately stopped and appropriate remedial measures are taken.

6. The method for rapid and environmentally friendly dismantling of an existing caisson according to claim 1 is characterized by: In step S3, the hook of the crane vessel (1) lowers the perforated pin steel rod (4) to the lifting hole position, and the diver accurately inserts the steel rod into the lifting hole underwater. The other end of the steel rod is inserted into the flange plate and the limit steel rod is inserted in sequence, and the pin is horizontal in the wall and symmetrical at both ends. The caisson (3) is pre-lifted, and the lifting device (2) on one side is lifted, and after the bottom of the caisson (3) on one side is separated from the mud surface, the lifting device (2) on the other side is lifted; The crane vessel (1) gradually lifts the hook, and the caisson (3) slowly rises to the sea surface, while water is drained from the sluice holes to reduce the weight; The caisson (3) is out of the water, the crane vessel (1) is kept in a stable position, the performance of the equipment is tested, and it is confirmed that the lifting device (2) is not deformed or damaged, and whether the wall of the caisson (3) lifting position is intact and has no cracks; Place the submersible pump in the caisson (3) and start pumping and draining water; The caisson (3) is further lifted to a point 1 meter above the top elevation of the temporary passage, and is then paused again for observation; The crane vessel (1) transfers the caisson (3) to a predetermined placement position at a uniform speed by horizontally anchoring. Finally, the crane vessel (1) slowly lowers the hook to accurately place the caisson (3) at a predetermined position in the temporary passage.

7. The method for rapid and environmentally friendly dismantling of an existing caisson according to claim 1 is characterized by: In step S4, the hydraulic breaker crushes the caisson (3) and cleans the debris to a designated disposal site.

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