Wharf dismantling construction method

Abstract

The invention relates to the technical field of wharf construction, in particular to a wharf dismantling construction method. According to the wharf dismantling construction method, special scheme approval and administrative permission are completed firstly, construction resources are put in place, special equipment qualification and special operator certificates are verified, old wharf completion drawings are researched and read, a precise cutting model is constructed, and a construction foundation is tamped; a specially-assigned person dispatches the ship to enter the site, the floating crane ship is accurately positioned and calibrated through an anchor weighing boat, it is guaranteed that the overwater operation standard is stable, various facilities are dismantled in a layered and classified mode, and structural instability is avoided; the dismantled components are uniformly transferred to a land area to be piled up and chiseled, and resource utilization is achieved; dynamic inspection is carried out in the whole process, and standard acceptance is carried out after completion. According to the method, multi-link safety risks are avoided, the construction efficiency is improved, the construction period is shortened, resource utilization and ecological protection are both considered, and it is guaranteed that engineering is completed safely, efficiently and greenly.

Description

Technical Field

[0001] This invention relates to the field of wharf construction technology, and in particular to a wharf demolition construction method. Background Technology

[0002] As a hub for water and land transportation, wharves may need to be demolished and rebuilt after long-term operation due to structural aging, functional upgrades, or adjustments to waterway planning. Wharf demolition projects are among the most dangerous sub-projects, involving multiple high-risk procedures such as water operations, high-altitude operations, lifting and hoisting, and cutting and crushing. Moreover, they are mostly located in important waterways such as the Yangtze River, with complex construction environments, imposing strict requirements on construction safety, navigation safety, and ecological environmental protection.

[0003] The following problems often exist in the demolition of existing wharves: First, the demolition sequence lacks scientific planning, which can easily lead to structural instability and collapse. This is especially true for wharves with multiple structural combinations, such as main wharves, workboat berths, approach bridges, and substations. Disorderly demolition can easily trigger a chain of safety risks. Second, the demolition process is not targeted enough. Appropriate cutting and lifting methods are not used for different types of components (such as steel bridges, concrete piers, PHC piles, and steel pipe piles), resulting in low construction efficiency and easy damage to the remaining structure or the surrounding environment. Third, the safety management of lifting operations is inadequate. Problems such as unstable anchoring of floating cranes, improper selection of lifting equipment, and non-standard lifting procedures can easily lead to safety accidents such as lifting injuries and falling objects. Fourth, environmental protection and navigation protection measures are inadequate. Direct discharge of cutting mud and random dumping of construction waste can easily pollute water bodies. The lack of effective warnings and poor communication in the construction area can affect the navigation safety of passing ships.

[0004] Furthermore, the dock demolition work faces complex environmental challenges, such as the plum rains, typhoons, and heavy fog in the Yangtze River basin, as well as constraints imposed by water flow and geological conditions on underwater operations, further increasing the difficulty and risk of construction. At the same time, existing construction methods have a low rate of resource utilization of the demolished materials, and some recyclable components have not been properly disposed of, resulting in resource waste.

[0005] Therefore, there is an urgent need for a standardized, technologically compatible, safe, and environmentally compliant wharf demolition construction method. This method should address the problems of high safety risks, low construction efficiency, and significant environmental impact in existing construction projects by scientifically planning the demolition sequence, optimizing the demolition process of each component, strengthening safety and environmental protection management and navigation guarantee measures, and ensuring the safe, efficient, and green implementation of the wharf demolition project.

[0006] In view of the above-mentioned shortcomings, the designer actively researched and innovated in order to create a dock demolition construction method that would have greater industrial value. Summary of the Invention

[0007] To address the aforementioned technical problems, the purpose of this invention is to provide a method for dismantling a wharf.

[0008] A method for dismantling a wharf according to the present invention includes the following steps: Step 1: Construction preparation, including scheme approval and procedures, personnel, machinery and materials placement and wharf structure preparation. The placement of personnel, machinery and materials requires checking the relevant certificates of special equipment and the certification status of special operation personnel. The wharf structure preparation requires analyzing the relevant as-built drawings of the old wharf and making a cutting model. Step 2: Vessel entry and positioning. Vessels at the construction site are under the unified command and dispatch of a designated person. After the floating crane vessel arrives at the construction position, it uses the anchor boat to anchor and position itself and correct the lifting and dismantling position. Step 3: Dismantle the wharf ancillary facilities, steel bridge, piers, berthing facilities and pile foundations in the preset order. The dismantling order is: old workboat berth, old approach bridge and end of main wharf, main wharf and remaining structure, anti-collision steel pipe piles and compensator piers on both sides of approach bridge, and substation piers. Step 4: Dismantling of materials. The materials will be transported to a temporary land storage site for crushing and resource utilization. Step 5: Conduct inspections and acceptance as required during and after construction.

[0009] The demolition method for this wharf is based on "early planning, orderly progress, and closed-loop management." First, the specialized construction plan was prepared and approved, and relevant administrative permits were obtained. Simultaneously, resources such as construction machinery, materials, and personnel were deployed. Special emphasis was placed on verifying the qualifications of special equipment and the certification of special operation personnel. At the same time, the as-built drawings of the old wharf were thoroughly studied, and a precise cutting model was constructed to lay the foundation for subsequent construction. Next, a dedicated team coordinated the entry of vessels into the site. After the floating crane arrived at the designated construction area, it was precisely anchored and positioned using an anchor-lifting boat to calibrate the lifting and dismantling posture, ensuring the stability of the waterborne operation benchmark. Subsequently... Following a scientific sequence of "old workboat berth → old approach bridge and main wharf end → main wharf and remaining structure → anti-collision steel pipe piles and compensator piers on both sides of the approach bridge → substation piers," the ancillary facilities, steel bridges, piers, berthing facilities, and pile foundations in each area were dismantled in layers and categories to avoid structural instability caused by disorderly demolition. The dismantled components were uniformly transported to a temporary land storage point, where they were crushed and recycled to reduce resource waste and environmental impact. Dynamic inspections were implemented throughout the construction process, and a comprehensive acceptance inspection was conducted according to specifications upon completion to ensure that each stage met safety, quality, and environmental protection requirements. This method, through standardized process design, precise process adaptation, and full-cycle management, effectively avoids safety risks in water operations, lifting, and structural cutting, while improving construction efficiency and shortening the construction period. Simultaneously, it achieves the dual goals of resource utilization of dismantled materials and ecological environmental protection, ensuring the safe, efficient, and green completion of the wharf demolition project.

[0010] Furthermore, the preparation of the wharf structure in step 1 also includes reviewing the external dimensions, quality, quantity, reserved holes, embedded parts and lifting points of each part of the wharf structure, checking the reliability of the supporting structure and whether the surrounding debris hinders dismantling and lifting.

[0011] During the wharf structure preparation phase, in addition to thoroughly analyzing the as-built drawings of the old wharf and building a precise cutting model, a professional technical team is required to conduct a comprehensive and meticulous on-site verification: verifying the actual dimensions, physical quality, and quantity of each structural component of the wharf, focusing on checking the positional accuracy of reserved holes, the anchoring strength of embedded parts, and the load-bearing compatibility of lifting points; simultaneously assessing the overall stability and reliability of the supporting structure; and thoroughly clearing away any surrounding debris that may interfere with the demolition and hoisting operations. Through this series of comprehensive and meticulous pre-processing steps, it is possible to ensure a full understanding of the actual condition of the wharf structure before construction, providing accurate data support for subsequent cutting, segmentation, and hoisting procedures. It also allows for the early identification of structural hazards and operational obstacles, preventing safety accidents and delays caused by parameter deviations, support failures, or spatial interference during construction, ultimately ensuring the accuracy, safety, and efficiency of the wharf demolition operation.

[0012] Furthermore, in step 3, when dismantling the steel bridge, first check the connection between the steel bridge and the pier. If there are any connected parts, cut them apart with a plasma cutter. Then, use a floating crane to lift the steel bridge onto a transport ship for transport. The steel bridge on the transport ship is placed symmetrically in the direction of the ship.

[0013] During the dismantling of the steel bridge, technicians first conduct a comprehensive inspection of the connection nodes between the steel bridge and the piers to clarify the connection method and its strength. If there are any areas where separation is not complete, such as welds or bolt tightening, a plasma cutter is used for precise cutting and dismantling to ensure that the steel bridge is completely separated from the piers without damaging surrounding structural components. Subsequently, a floating crane of appropriate tonnage is deployed to smoothly lift the steel bridge according to the preset lifting points and slowly transfer it to a transport ship. During transportation, the principle of symmetrical placement along the ship's direction is strictly followed to ensure balanced and stable stress on the ship. This standardized and orderly operation process not only achieves the safe separation of the steel bridge from the piers, avoiding structural collapse or component damage caused by improper handling of connection points during dismantling, but also reduces the safety risks of lifting operations and water transportation through precise lifting by the floating crane and reasonable placement on the transport ship, improving the efficiency of dismantling and transfer, and providing strong support for the further processing of dismantled materials and the maintenance of on-site construction order.

[0014] Furthermore, in step 3, when dismantling the pier, the concrete blocks are cut into sections along the middle of the pile foundation using a concrete wire saw. The weight of each block is controlled between 70-90t. The cutting line avoids the pile foundation. The last row of concrete blocks is symmetrical and supported by no less than two pile foundations. The cut concrete blocks are then hoisted by a floating crane to the remaining dock or barge for further disassembly and transported off-site.

[0015] During the pier demolition operation, the cutting path along the middle area of ​​the pile foundation was precisely planned based on the pile foundation distribution pattern and the lifting capacity of the floating crane. This ensured that the cutting line cleverly avoided the pile foundation to prevent structural damage. The pier was precisely divided into sections using a concrete wire saw, with each section weighing 70-90 tons. The arrangement of the last row of concrete blocks was strictly controlled to ensure symmetry and stable support from at least two pile foundations. After cutting, the concrete sections were smoothly lifted by the floating crane onto the remaining wharf surface or a dedicated barge. After further dismantling to suitable transport sizes, they were then transported off-site for disposal. This method, through scientific planning of the cutting path and sectioning parameters, ensured the stability of the remaining structure during pier demolition, avoiding the risk of collapse due to stress imbalance. It also adapted to the lifting capacity of the floating crane, improving the safety and efficiency of the lifting operation. Furthermore, the components after secondary dismantling were easier to transport and dispose of, effectively shortening the construction cycle and ensuring the safe, orderly, and efficient progress of the pier demolition operation.

[0016] Furthermore, in step 3, when dismantling the pile foundation, PHC piles and cast-in-place piles are cut down to the design elevation using a wire saw, while steel pipe piles are dismantled using a cutting process. If cutting is not possible, a floating crane is used in conjunction with a vibratory hammer to remove them. Before cutting, divers use a high-pressure water gun to clean the silt around the pile body.

[0017] Differentiated demolition strategies are adopted based on the structural characteristics of different types of pile foundations: For PHC piles and cast-in-place piles, divers first dive underwater and use high-pressure water jets to thoroughly flush and clean the silt around the pile body, exposing a clear cutting surface. Then, wire saws are used to make precise cuts along the preset design elevation, ensuring that the demolition end face is flat and meets the elevation requirements. For steel pipe piles, divers also clean the surrounding silt first and then use cutting technology to complete the demolition. If the cutting is obstructed due to reasons such as pile corrosion, deformation, or excessive embedment in the soil, a combination of floating crane and vibratory hammer is used. The floating crane fixes the pile body, and the vibratory hammer generates high-frequency excitation force to separate the pile body from the soil, and finally the steel pipe pile is safely removed. This categorized approach to demolition, prioritizing obstacle removal before commencement of work, not only adapts to the different materials and structural characteristics of pile foundations, ensuring the targeted and effective nature of the demolition operation, but also eliminates the impact of silt on cutting precision through diver dredging, mitigates construction risks by utilizing the minimally invasive nature of wire saw cutting and the high efficiency of vibratory hammer extraction, and simultaneously ensures accurate pile foundation demolition elevation, safe and controllable operation process, avoids disturbance to the surrounding water environment and adjacent structures, and guarantees the overall quality and progress of the demolition project.

[0018] Furthermore, in step 3, when dismantling the substation and part of the approach bridge, the substation, being a brick-concrete structure, was dismantled using an excavator. The hollow slab beams of the approach bridge and compensator were cut into sections by a wire saw and then dismantled by a floating crane. Areas that the floating crane could not reach were broken up and cleared on-site by excavators placed on the bridge deck.

[0019] For the demolition of substations and some approach bridges, a categorized and adapted construction method was adopted: For substations with brick-concrete structures, excavators of appropriate tonnage were selected, and demolition was carried out from top to bottom, layer by layer, to avoid structural collapse and safety risks; for hollow slab beams of approach bridges and compensators, they were first precisely cut into sections using wire saws to ensure that the weight of each component met the lifting load requirements of the floating crane, and then the floating crane was used to smoothly lift, dismantle, and transport the sections; for areas not covered by the floating crane's operating radius, excavators were strategically positioned on the bridge deck to crush the components to be demolished in those areas on-site, and then the debris was promptly cleaned up to avoid accumulation and obstruction of construction traffic. This categorized and site-specific demolition method not only adapts to the demolition characteristics of different structural types, ensuring the safety and efficiency of the construction process, but also minimizes disturbance to surrounding structures that have not yet been demolished through precise cutting and targeted operations, while timely debris removal avoids environmental pollution and traffic obstruction, ultimately achieving the orderly progress of the demolition of substations and some approach bridges, meeting the overall construction schedule and safety and environmental protection requirements.

[0020] Furthermore, when using a diamond wire saw for demolition in step 3, it is necessary to determine the location of the cutting section, drill lifting holes and rope holes, install and fix the guide wheel and wire saw machine, connect the operating system, ensure that the diamond wire runs at a linear speed of 20±5m / s during the cutting process, and supply sufficient circulating cooling water.

[0021] In the diamond wire saw cutting operation during the dock demolition, the cutting section position was first precisely marked based on the structural characteristics of the components and the hoisting requirements. Simultaneously, holes were drilled at the pre-set lifting points to create hoisting holes and wire threading holes. The guide wheel and wire saw were then securely installed in the designed position, ensuring accurate positioning. After connecting and debugging the operating system, the cutting operation was started. During the cutting process, the linear speed of the diamond wire was strictly controlled, maintaining it stably within a reasonable range of 15-25 m / s. Sufficient circulating cooling water was continuously supplied to ensure cooling and dust suppression in the cutting area throughout the process. This standardized and orderly operation process ensures a smooth and dimensionally accurate cutting section through precise positioning and installation, meeting subsequent hoisting and transportation requirements. Stable linear speed control improves cutting efficiency and extends the lifespan of the diamond wire. The continuous supply of circulating cooling water effectively avoids the impact of high cutting temperatures on component performance and dust pollution. Ultimately, this achieves precise, efficient, and environmentally friendly cutting operations, laying a solid foundation for the safe progress of the overall demolition project.

[0022] Furthermore, before lifting operations in step 3, the crane pulleys, slings, shackles and other components must be inspected. When lifting, the component should be lifted 200-300mm off the ground and then stopped to check the stability of the crane and the reliability of the braking device. When operating a floating crane, the hull must be securely anchored and the lifting equipment must be firmly suspended. It is strictly forbidden to pull the hook horizontally or to run aground at one angle. Lifting operations are prohibited in winds of level 6 or above.

[0023] Before lifting operations, a comprehensive and meticulous inspection should be conducted on key load-bearing components of the crane, such as pulleys, slings, and shackles, to identify potential hazards such as wear, corrosion, and cracks, ensuring that the components are in good working order and meet safety operation standards. During the initial lifting phase, the component should be slowly lifted 200 to 300 mm off the ground, after which operations should be paused. The overall stability of the crane, the sensitivity and reliability of the braking device, and the firmness of the connection between the lifting equipment and the component should be carefully checked. Lifting can only continue after confirming there are no abnormalities. For floating crane operations, reliable anchoring methods must be used to ensure the stability of the vessel and to ensure a secure connection between the lifting equipment and the component. Strictly prohibit illegal operations such as horizontal hook lifting and grounding of the vessel at a single angle. Close attention should also be paid to weather changes, and all lifting operations should be immediately stopped in the event of winds of level six or above. Through this series of comprehensive and high-standard safety management measures, we can effectively avoid safety accidents such as falls and collisions caused by component failures, equipment instability, improper operation, or severe weather during the lifting and hoisting process. This ensures the safety of workers, equipment, and surrounding structures, and guarantees the standardized and orderly progress of the lifting and hoisting process, providing strong support for the safe and efficient implementation of the overall wharf demolition project.

[0024] Furthermore, in step 4, before the concrete block crushing operation, technical safety briefings, equipment maintenance, and lighting installation must be completed. During the crushing process, the distance between excavator positions should be greater than 10m of their working radius to avoid the risk of cross-operation. Waste oil and waste liquid should be centrally stored and treated. Cutting mud should be collected and settled in a special container. The settled mud should be filtered through geotextile and then discharged. The sediment should be transported off-site for disposal.

[0025] During the demolition and disposal phase, for concrete block crushing operations, a comprehensive technical and safety briefing was conducted for all personnel before construction began. This briefing clarified the work process, risk points, and protective measures. Simultaneously, a comprehensive inspection and debugging of the crushing equipment was completed to ensure stable equipment performance. Sufficient lighting facilities were installed as needed to ensure clear visibility during operations. During the crushing process, the excavator layout was scientifically planned to ensure that the distance between excavator positions exceeded their own working radius by more than 10 meters, spatially eliminating safety risks such as collisions caused by overlapping operations. Waste oil and waste liquid generated during construction were collected and stored in dedicated containers for compliant treatment. Cutting slurry was introduced into dedicated collection containers for sedimentation treatment. After sedimentation, the upper layer of clean water was filtered through geotextile to meet standards before being discharged, while the bottom sediment was collected separately and transported to a designated disposal site. This treatment method, through thorough pre-construction preparation, scientific process control, and compliant disposal of waste, ensured the safe, orderly, and efficient progress of concrete block crushing operations while effectively preventing pollution of surrounding water bodies and soil environments by waste oil, waste liquid, and cutting slurry. It achieved a synergistic unity between demolition operations and environmental protection requirements, contributing to the overall goals of safety, environmental protection, and efficiency of the project.

[0026] Furthermore, during the construction process, a construction area was demarcated, and a patrol boat was deployed approximately 200 meters upstream and downstream of the construction area. An emergency tugboat was also deployed at the construction site. Construction vessels displayed their lights and shapes as required, and buoys with self-illuminating lights were moored to the anchor chains at 50-meter intervals. A construction communication network was established via VHF maritime channels to ensure smooth communication between the ship and the shore.

[0027] During construction, a dedicated construction area was clearly demarcated, with a patrol boat deployed 200 meters upstream and downstream to conduct 24 / 7 patrols. An emergency tugboat was also stationed at the site to handle unforeseen circumstances. Construction vessels strictly adhered to inland waterway navigation regulations, displaying their lights and shapes in accordance with these standards. Self-illuminating buoys were attached to the anchor chains every 50 meters to clearly mark the boundaries of the work area. Furthermore, a dedicated VHF maritime communication network was established to ensure uninterrupted real-time communication between vessels and the shore command center, as well as between vessels themselves. These comprehensive navigation safety measures effectively warned passing vessels to stay away from the construction area, preventing unauthorized vessels from entering and causing collisions or other accidents. The emergency tugboat provided rapid response to emergencies, the standardized lights and shapes and self-illuminating buoys enhanced the visibility of the construction area, and the uninterrupted communication network ensured timely transmission of construction instructions and real-time feedback on site conditions. Ultimately, this created a safe and orderly maritime working environment for the wharf demolition work, balancing construction progress with navigation safety.

[0028] By means of the above-described solution, the present invention has at least the following advantages: 1. Reduce safety risks; avoid structural instability and collapse by planning a scientific dismantling sequence; adopt appropriate dismantling processes for different components to reduce structural disturbance; strengthen the whole process control of lifting and hoisting and the investigation of hidden dangers before construction to ensure the safety of operation and structure in all aspects.

[0029] 2. Improve construction efficiency; with “early planning and orderly progress” as the core, improve early preparation and ship scheduling, adopt classified and adapted demolition methods to solve operational problems, realize efficient circulation of demolished materials, and standardize processes to greatly improve efficiency and shorten the construction period.

[0030] 3. Practice green construction; strictly implement environmentally friendly disposal of waste, centrally treat waste oil and waste liquid, and discharge cutting mud after filtering to meet standards; use circulating cooling water for wire saw cutting to suppress dust and avoid environmental pollution.

[0031] 4. Ensure navigation safety; demarcate exclusive construction waters, deploy warning boats and emergency tugboats, standardize vessel markings to improve recognizability; build a VHF communication network to achieve real-time linkage, taking into account both construction and waterway safety.

[0032] 5. Improve resource utilization; after centralized transportation of demolished materials, they are recycled and utilized to reduce waste of recyclable components and enhance the economic and social benefits of the project.

[0033] 6. Enhance environmental adaptability; through full-process control and differentiated processes, effectively cope with complex aquatic environments and severe weather, and ensure the stable progress of the project.

[0034] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0035] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show a certain embodiment of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of the framework principle of the present invention. Detailed Implementation

[0037] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0038] In the early stages of construction, the preparation and approval of a specialized plan and the filing of relevant traffic and construction permits were completed. Simultaneously, personnel, machinery, and materials were in place. Special attention was paid to verifying the relevant certificates for special equipment and the certification status of special operation personnel. In addition, the as-built drawings of the old wharf were thoroughly analyzed, and a cutting model was created. Key parameters such as the external dimensions, quality, quantity, reserved holes, embedded parts, and lifting points of each part of the wharf structure were reviewed. The reliability of the supporting structure was checked, and surrounding debris hindering dismantling and hoisting was cleared. Subsequently, a designated person directed and coordinated the vessels at the construction site. Once the floating crane reached the designated construction position… Anchoring and positioning were completed using an anchor-lifting boat, and the lifting and dismantling positions were precisely corrected. Then, following a pre-set sequence: "old workboat berth → old approach bridge and main wharf end → main wharf and remaining structure → anti-collision steel pipe piles and compensator piers on both sides of the approach bridge → substation piers," the wharf ancillary facilities, steel bridges, piers, berthing facilities, and pile foundations in each area were dismantled sequentially. After dismantling, the materials were transported to a temporary land storage site for crushing and resource utilization. Dynamic inspections were continuously conducted throughout the construction process, and a comprehensive acceptance inspection was carried out according to established standards upon completion. Through scientific planning of construction preparation, vessel positioning, dismantling sequence, waste disposal, and acceptance, and by clarifying the core control points of each process, the project ensured both standardization and safety, improved construction efficiency, and achieved resource utilization of dismantled materials, reducing resource waste and environmental impact, thus ensuring the efficient and orderly progress of the wharf demolition project.

[0039] Based on a thorough analysis of the old wharf's as-built drawings and the precise fabrication of cutting models, professional technicians conducted a comprehensive review of all key structural components of the wharf. They verified core parameters such as dimensions, actual weight, and quantity, focusing on the accuracy of pre-drilled holes, the robustness of embedded parts, and the load-bearing capacity of lifting points. Simultaneously, they systematically checked the stability and reliability of the supporting structure, clearing away any surrounding debris that might obstruct dismantling and lifting operations. This ensured that all structural parameters matched the design documents, the support system was safe and stable, and the workspace was unobstructed. Through this comprehensive and meticulous structural review and pre-processing, risks to demolition work caused by structural parameter deviations, support failures, or spatial obstacles could be identified and mitigated in advance. This provides accurate basic data support for subsequent ship positioning and orderly dismantling procedures, ensuring the safety, accuracy, and efficiency of the demolition operation and preventing work stoppages or safety accidents due to structural problems during construction.

[0040] Before the demolition work, the cutting line along the middle of the pile foundation is determined based on the structural characteristics of the pier and the lifting capacity of the floating crane. This ensures that the cutting line accurately avoids the pile foundation to prevent damage. The block division scheme is planned according to the standard of 70-90t per block. At the same time, it is ensured that the last row of concrete blocks is symmetrically distributed and is stably supported by no less than two pile foundations. Then, concrete wire saws are used to accurately cut the blocks along the preset cutting line. During the cutting process, the cutting progress and the stability of the concrete blocks are monitored in real time. After the blocks are divided, the concrete blocks are smoothly lifted by the floating crane to the remaining dock or barge. The concrete blocks are then further decomposed on the dock or barge. Finally, the decomposed components are transported to the site in an orderly manner. By scientifically planning the cutting route and the weight of each block, the load-bearing requirements of the floating crane are met while protecting the pile foundation structure from damage. The symmetrical arrangement of the last row of concrete blocks and the multi-pile foundation support design ensure the stability of the remaining structure of the pier during the cutting process. The precision of the concrete wire saw cutting reduces the disturbance to the surrounding structure. The connection process between the floating crane hoisting and the subsequent dismantling and transportation improves the construction efficiency and effectively avoids problems such as structural instability and hoisting risks that may occur during the pier demolition, ensuring the safe and orderly progress of the demolition operation.

[0041] Before demolition, the type of pile foundation and the design demolition elevation are first determined. For PHC piles and cast-in-place piles, divers first use high-pressure water guns to thoroughly clean the silt around the pile body to ensure that there are no debris obstructing the cutting area. Then, a wire saw is used to precisely cut and demolish the pile along the design elevation. For steel pipe piles, divers also first clean the silt around the pile body and then use the cutting process to demolish the pile along the design elevation. If the pile cannot be cut due to rust, deformation, or other reasons, a suitable floating crane and vibratory hammer are used. The floating crane fixes the pile body, and the vibratory hammer generates excitation force to separate the pile body from the soil and remove the steel pipe pile. The condition of the pile body and the accuracy of the demolition elevation are monitored in real time during the demolition of all types of pile foundations. Adaptive demolition techniques are employed based on the characteristics of different types of pile foundations to ensure the targeted and effective demolition operations. Divers clear silt in advance to provide a clear working surface for the cutting operation, ensuring the accuracy of the cutting elevation. The minimally invasive nature of wire saw cutting and the high efficiency of vibratory hammer extraction are adapted to different pile foundations and site conditions, avoiding the limitations of a single demolition method. Full-process monitoring effectively avoids safety risks caused by pile shaking and elevation deviation during pile foundation demolition, ensuring that the pile foundation demolition meets design requirements and does not affect the surrounding water environment or structural safety.

[0042] Before dismantling, a professional team conducted a comprehensive and detailed inspection of the connection points between the steel bridge and the piers, clarifying the connection methods and their strength. If any welded or bolted connections were found, a plasma cutter was immediately used to precisely separate the connections, ensuring the steel bridge was completely detached from the piers without damaging the surrounding structure. After cutting, a floating crane of appropriate tonnage was used to smoothly lift the steel bridge from the pre-set lifting points and slowly transfer it to the transport vessel. The bridge's posture was monitored throughout the lifting process to prevent collisions or imbalances. On the transport vessel, the steel bridge was symmetrically placed in the same direction as the ship to ensure balanced load distribution. This precise separation method, involving inspection before cutting, effectively prevented accidental damage to the piers and surrounding structures during dismantling. The standardized operation of the floating crane and symmetrical placement on the transport vessel ensured the safety and stability of the lifting operation and prevented the steel bridge from capsizing or the ship from tilting during transport due to improper placement. This significantly improved the safety and efficiency of the entire dismantling and transfer process, while also laying a solid foundation for further processing of the dismantled materials.

[0043] The detailed workflow for the demolition of the substation and part of the approach bridge in step 3 is as follows: First, clarify the demolition scope and the types of structures. For the brick-concrete substation, select an appropriate model of excavator and carry out the demolition work according to the principle of top-down and layered dismantling to avoid overall structural collapse. For the hollow slab beams of the approach bridge and compensator, first, combine the beam size, weight and floating crane lifting capacity to plan the wire saw cutting and segmentation scheme. After determining the cutting section position, carry out precise cutting and segmentation. After segmentation, use the floating crane to smoothly lift and dismantle the components to the transport carrier for off-site transportation. For areas that cannot be covered by the floating crane's operating radius, scientifically plan the excavator deployment points on the bridge deck. Use the excavator to crush the components in the area on-site. After crushing, clean up the waste in time to ensure that the working surface is clean and unobstructed. Differentiated dismantling processes were adopted based on the different structural characteristics of the substation, approach bridge, and compensator, ensuring the targeted and safe nature of the dismantling operation. The method of cutting sections with wire saws and using floating cranes for dismantling reduced disturbance to the surrounding structures, while the on-site crushing and debris removal by excavators effectively solved the dismantling problem in areas that the floating cranes could not cover. The overall process was smooth, which not only improved the efficiency of the dismantling operation but also avoided the safety risks caused by disorderly dismantling, laying a good foundation for the subsequent dismantling of other structures.

[0044] The detailed workflow for diamond wire saw cutting and demolition in step 3 is as follows: Before the operation, the structural parameters of the component to be demolished and the subsequent hoisting and transportation requirements are considered. The cutting section position is accurately surveyed and marked. Then, according to the cutting path and hoisting plan, hoisting holes and rope holes of appropriate specifications are drilled at the preset position of the component. Subsequently, the guide wheel and the wire saw are accurately aligned and firmly fixed on the working platform. The connection and debugging of the operating system and the wire saw are completed to ensure that the equipment is operating normally. During the cutting process, the linear speed of the diamond wire is monitored and adjusted in real time to keep it stably within a reasonable range of 15-25m / s. At the same time, sufficient circulating cooling water is continuously supplied to ensure the cooling effect and dust suppression effect of the cutting area. Through precise planning and standardized equipment installation in the early stages, the flatness and dimensional accuracy of the cut surface were ensured, meeting the connection requirements of subsequent hoisting and transportation. Stable linear speed control improved cutting efficiency and extended the service life of the diamond rope. Sufficient circulating cooling water effectively avoided the impact of high cutting temperatures on component performance and dust pollution. The overall process was standardized and controllable, which reduced the safety risks of cutting operations and improved the accuracy and environmental friendliness of the operations, providing a strong guarantee for the orderly progress of subsequent dismantling.

[0045] The detailed workflow for lifting and hoisting operations in step 3 is as follows: Before the operation, professional personnel will conduct a comprehensive and meticulous inspection of the crane's key load-bearing components such as pulleys, slings, and shackles to identify potential safety hazards such as wear, corrosion, and cracks, ensuring that all components are in good working order and meet safety operation standards. During the lifting operation, the component will be slowly lifted 200-300mm off the ground and the operation will be paused. The overall stability of the crane, the sensitivity and reliability of the braking device, and the firmness of the connection between the lifting equipment and the component will be checked. The lifting operation will continue only after confirming that there are no abnormalities. For floating crane operations on water, the hull must be securely anchored in advance to ensure that the lifting equipment and the component are firmly suspended. It is strictly forbidden to pull the hook horizontally or to run aground at one corner of the hull. At the same time, a dedicated person will be assigned to monitor weather changes in real time. When encountering winds of level 6 or above, all lifting operations will be stopped immediately. By conducting comprehensive component inspections before operations, performing trial lifts and verifications during the initial lifting phase, implementing standardized management of water operations, and strictly prohibiting lifting in severe weather, safety accidents such as falls and collisions caused by component failures, equipment instability, improper operation, or sudden weather changes during the lifting and hoisting process were avoided from the outset. This ensured the safety of personnel, equipment, and surrounding structures, while also ensuring that the lifting and hoisting process proceeded in a standardized and orderly manner, providing a solid guarantee for the safe and efficient implementation of the overall wharf demolition project.

[0046] The detailed workflow for handling demolished materials in step 4 is as follows: For concrete block crushing operations, a comprehensive technical and safety briefing is conducted for the operators before construction to clarify the operation process, key points of risk prevention and control, and operating procedures. At the same time, the equipment required for crushing is fully inspected and debugged to ensure stable and reliable equipment performance. Sufficient lighting facilities are installed according to the needs of the working environment to ensure clear visibility. During crushing operations, the excavator working area is scientifically planned, and the spacing between excavator positions is strictly controlled to ensure that the spacing is more than 10m greater than the working radius of each excavator, thereby eliminating safety risks such as collisions caused by cross-operations. Meanwhile, waste oil and waste liquid generated during construction are collected and stored in special containers and disposed of in a unified and compliant manner. The mud generated from cutting is introduced into a special collection container for sedimentation treatment. After the mud settles, the upper layer of clean water is filtered through geotextile to meet the standards before being discharged, and the bottom sediment is collected separately and transported to a designated compliant location for disposal. Through thorough preparation before construction, scientific management during construction, and compliant disposal of waste, the safe and orderly progress of concrete block crushing operations was ensured, effectively reducing the risks of cross-operations and equipment malfunctions. It also prevented waste oil, waste liquid, and cutting mud from polluting the surrounding water and soil environment, achieving a balance between demolition efficiency and environmental protection requirements, and laying a solid foundation for the compliant acceptance of the entire wharf demolition project.

[0047] First, based on the construction scope, operational needs, and navigation requirements, the boundaries of the construction water area are accurately demarcated and marked. Then, a patrol boat is deployed approximately 200 meters upstream and downstream of the demarcated water area to patrol and guard around the clock, promptly driving away unrelated vessels and preventing navigation risks. At the same time, an emergency tugboat is positioned at the construction site to deal with emergencies such as ship grounding and collisions. Construction vessels must strictly comply with relevant maritime management regulations, displaying the corresponding lights and shapes in a standardized manner, clearly indicating their operational status, and attaching self-illuminating buoys to the anchor chains every 50 meters to further clarify the scope of the operational water area and ensure operational safety at night or in low visibility conditions. In addition, a construction communication network centered on VHF maritime channels is established to ensure smooth real-time communication between vessels and the shore command center and various operational vessels, enabling timely transmission of construction instructions and synchronous feedback of on-site dynamics. Through comprehensive waterway management, robust emergency response, standardized signage and warnings, and seamless communication, the construction area can be effectively isolated from navigable waters, significantly reducing the risk of collisions caused by unrelated vessels entering the waters. The deployment of emergency tugboats enables rapid response to emergencies, enhancing emergency handling capabilities. Standardized lights and self-illuminating buoys enhance the visibility of the work area, and a smooth communication network ensures efficient and precise construction scheduling. Ultimately, this creates a safe and orderly working environment for the dock demolition operations, balancing construction progress with navigation safety and ensuring the smooth progress of the overall project.

[0048] Finally, the following points should be noted: First, in the description of this application, it should be noted that, unless otherwise specified and limited, the terms "installation", "connection", and "linkage" should be interpreted broadly, and can be mechanical or electrical connections, or internal connections between two components, or direct connections. "Up", "down", "left", "right", etc. are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may change. Secondly: The accompanying drawings of the embodiments disclosed in this invention only involve the structures involved in the embodiments disclosed in this invention. Other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of this invention can be combined with each other. Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for dismantling a wharf, characterized in that, Includes the following steps: Step 1: Construction preparation, including scheme approval and procedures, personnel, machinery and materials placement and wharf structure preparation. The placement of personnel, machinery and materials requires checking the relevant certificates of special equipment and the certification status of special operation personnel. The wharf structure preparation requires analyzing the relevant as-built drawings of the old wharf and making a cutting model. Step 2: Vessel entry and positioning. Vessels at the construction site are under the unified command and dispatch of a designated person. After the floating crane vessel arrives at the construction position, it uses the anchor boat to anchor and position itself and correct the lifting and dismantling position. Step 3: Dismantle the wharf ancillary facilities, steel bridge, piers, berthing facilities and pile foundations in the preset order. The dismantling order is: old workboat berth, old approach bridge and end of main wharf, main wharf and remaining structure, anti-collision steel pipe piles and compensator piers on both sides of approach bridge, and substation piers. Step 4: Dismantling of materials. The materials will be transported to a temporary land storage site for crushing and resource utilization. Step 5: Conduct inspections and acceptance as required during and after construction.

2. The wharf demolition construction method according to claim 1, characterized in that, The preparation of the wharf structure in step 1 also includes reviewing the external dimensions, quality, quantity, reserved holes, embedded parts and lifting points of each part of the wharf structure, checking the reliability of the supporting structure and whether the surrounding debris will hinder dismantling and lifting.

3. The wharf demolition construction method according to claim 1, characterized in that, When dismantling the steel bridge in step 3, first check the connection between the steel bridge and the pier. If there are any connected parts, cut them apart with a plasma cutter. Then, use a floating crane to lift the steel bridge onto a transport ship for transport. The steel bridge on the transport ship is placed symmetrically in the direction of the ship.

4. The wharf demolition construction method according to claim 1, characterized in that, In step 3, when dismantling the pier, the concrete blocks are cut into sections along the middle of the pile foundation using a concrete wire saw. The weight of each block is controlled between 70-90t. The cutting line avoids the pile foundation. The last row of concrete blocks is symmetrical and supported by no less than two pile foundations. The cut concrete blocks are then hoisted by a floating crane to the remaining dock or barge for further disassembly and transported off-site.

5. The wharf demolition construction method according to claim 1, characterized in that, In step 3, when removing the pile foundation, PHC piles and cast-in-place piles are removed to the design elevation using wire saw cutting, while steel pipe piles are removed using cutting technology. If cutting is not possible, a floating crane is used in conjunction with a vibratory hammer to remove them. Before cutting, divers use high-pressure water guns to clean the silt around the pile body.

6. The wharf demolition construction method according to claim 1, characterized in that, In step 3, when dismantling the substation and part of the approach bridge, the substation, which is a brick-concrete structure, was dismantled by an excavator. The hollow slab beams of the approach bridge and compensator were cut into sections by a wire saw and then dismantled by a floating crane. Areas that the floating crane could not reach were broken up and the debris was cleared on-site by excavators placed on the bridge deck.

7. The wharf demolition construction method according to claim 1, characterized in that, When using a diamond wire saw for demolition in step 3, it is necessary to determine the location of the cutting section, drill lifting holes and rope holes, install and fix the guide wheel and wire saw machine, and connect the operating system. During the cutting process, ensure that the linear speed of the diamond wire is 20±5m / s and supply sufficient circulating cooling water.

8. The wharf demolition construction method according to claim 1, characterized in that, Before lifting operations in step 3, the crane pulleys, slings, shackles and other components must be inspected. When lifting, the component should be lifted 200-300mm off the ground and then stopped. The stability of the crane and the reliability of the braking device should be checked. When operating a floating crane, the hull must be securely anchored and the lifting equipment must be firmly suspended. It is strictly forbidden to pull the hook horizontally or to run aground at one angle. Lifting operations are prohibited in winds of level 6 or above.

9. The wharf demolition construction method according to claim 1, characterized in that, In step 4, before the concrete blocks are crushed, technical safety briefings, equipment inspections, and lighting installations must be completed. During the crushing process, the distance between excavator positions should be greater than 10m of their working radius to avoid the risk of cross-operations. Waste oil and waste liquid should be centrally stored and treated. Cutting slurry should be collected and settled in a special container. The settled slurry should be filtered through geotextile before being discharged, and the sediment should be transported off-site for disposal.

10. The wharf demolition construction method according to claim 1, characterized in that, During construction, a construction area was demarcated, and a patrol boat was deployed 200 meters upstream and downstream of the construction area. An emergency tugboat was also deployed at the construction site. Construction vessels displayed their lights and shapes as required, and buoys with self-illuminating lights were moored to the anchor chains at 50-meter intervals. A construction communication network was established through VHF maritime channels to ensure smooth communication between ships and shore.

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