Construction method of double-row steel sheet pile cofferdam

Abstract

The construction method of the double-row steel sheet pile cofferdam comprises the steps that hooks, winches wound with steel cables and fixed pulleys used for guiding the extending directions of the steel cables are arranged on steel sheet piles at intervals in the height direction of the steel sheet piles, the steel cables led out of the winches are wound around the fixed pulleys, and the free ends of the steel cables are connected to the hooks; the steel sheet piles are driven into an underwater foundation to form two rows of water retaining walls arranged at intervals, the hooks, the winches and the fixed pulleys are located on the opposite side faces of the two rows of water retaining walls respectively, and the fixed pulleys are located below the corresponding winches. The two steel cables, fixed to the hooks, of the two rows of water retaining walls are unfastened in sequence, then the free ends of the two steel cables are connected through the rope adapter, the winch is operated to tension the steel cables, the connected steel cables can apply first horizontal tension force pointing to the water retaining walls through the fixed pulleys, and therefore the lateral deformation resisting capacity of the water retaining walls is enhanced; the technical problem that in a double-row steel sheet pile cofferdam building main body, the rigidity of a water retaining wall body for resisting lateral stress is insufficient is solved.

Description

Technical Field

[0001] The present application relates to the technical field of establishing dry land construction sites in water areas, and in particular to a construction method for a double-row steel sheet pile cofferdam. Background Art

[0002] The double-row steel sheet pile water retaining cofferdam is an efficient and reliable temporary water retaining structure widely used in water-related projects such as cross-sea bridges, deep-water ports, and water conservancy hubs. The structure consists of two parallel rows of steel sheet piles, with soil and stone or grouting materials filled between the two rows of steel sheet piles to form a composite gravity retaining wall structure. The two rows of steel sheet piles are firmly connected by connecting buckles, which not only enhances the overall rigidity and anti-slip ability, but also effectively improves the anti-seepage performance. The structure has little disturbance to the surrounding soil, fast construction speed, and is reusable, with good economy and environmental adaptability. Its main function is to isolate the water body, keep the construction area dry, and ensure the safe construction of underwater structures such as bridge piers and sluices. It can also be used for emergency projects such as river diversion and temporary flood control. It is an indispensable and important support system in the current construction of water-related projects.

[0003] Despite the numerous advantages of double-row steel sheet pile cofferdams, they still present certain structural stability issues in practical applications. As the cofferdam height increases, the lateral pressure generated by the soil inside the cofferdam increases exponentially. When this pressure exceeds the bending bearing capacity of the steel sheet piles, it can easily cause the bottom of the piles to shift outward, resulting in so-called "kick-up" deformation. Once this deformation occurs, it can cause the entire cofferdam to become unstable or even collapse, seriously threatening construction safety. Therefore, traditional double-row steel sheet pile cofferdams are mostly suitable for low-height, low-head projects. To alleviate this problem, two reinforcement measures are commonly adopted in existing technologies: one is to dump stones at the bottom of the outer side of the steel sheet piles, using their deadweight to create counterpressure to offset some of the lateral pressure; the other is to reinforce the foundation with cement-mixed piles to increase the soil's ability to restrain the steel sheet piles and enhance overall stability.

[0004] While the aforementioned reinforcement methods have improved the deformation resistance of double-row steel sheet pile cofferdams to a certain extent, significant technical drawbacks remain. First, the use of riprap counterpressure requires a large amount of stone, resulting in high transportation and construction costs, and occupies construction space, impacting subsequent operational efficiency. Second, cement mixing piles have a long construction cycle and are particularly difficult to construct underwater, where they are susceptible to interference from factors such as water flow and sediment. This makes it difficult to control the quality of the mixing piles and prevents them from achieving effective reinforcement. More importantly, both methods are passive reinforcement methods that can only slow or limit the deformation of the steel sheet piles to a certain extent, but cannot fundamentally prevent the bending deformation of the steel sheet piles caused by excessive lateral pressure. Consequently, their effectiveness in resisting lateral deformation is relatively limited, making it difficult to meet the practical needs of high-head, deep cofferdam projects. Therefore, there is an urgent need to develop a structural design or construction method that actively reinforces the steel sheet pile structure to improve the overall bearing capacity and deformation resistance of the cofferdam and overcome the limitations of existing technologies. Summary of the Invention

[0005] In the embodiments of the present application, a construction method for a double-row steel sheet pile cofferdam is provided to solve the technical problem of insufficient rigidity of the retaining wall in the main body of the double-row steel sheet pile cofferdam structure in resisting lateral stress. The technical solution is as follows: In an embodiment of the present application, a method for constructing a double-row steel sheet pile cofferdam is provided, comprising: providing hooks, a winch wound with a steel cable, and a fixed pulley for guiding the extension direction of the steel cable at intervals along the height direction of the steel sheet piles; passing the steel cable led out of the winch around the fixed pulley, and connecting the free end of the steel cable to the hook; The steel sheet piles are driven into the underwater foundation to form two rows of spaced-apart retaining walls. The hooks, winches and fixed pulleys are respectively located on opposite sides of the two rows of retaining walls, and the fixed pulleys are located below the corresponding winches. The two steel cables fixed on the hooks of the two rows of water retaining walls are untied in turn, and then the free ends of the two steel cables are connected to each other through a rope adapter. The winch is operated to tension the steel cables so that the connected steel cables can apply a first horizontal tensioning force directed to the water retaining wall through the fixed pulley to enhance the water retaining wall's ability to resist lateral deformation. The intensity of the first horizontal tensioning force can be adjusted in real time through underwater synchronous monitoring of the water retaining wall.

[0006] In one embodiment, after sequentially untying two steel cables fixed to hooks of two rows of water retaining walls, connecting the free ends of the two steel cables to each other via a rope adapter, operating a winch to tension the steel cables so that the connected steel cables can apply a first horizontal tensioning force directed toward the water retaining wall via a fixed pulley to enhance the ability of the water retaining wall to resist lateral deformation, and regulating the intensity of the first horizontal tensioning force in real time through underwater synchronous monitoring of the water retaining wall, the method further includes: Fill the space between the two rows of retaining walls with soil. During the filling process, according to the soil filling height and the deformation of the steel sheet piles, the winch is synchronously operated to dynamically adjust the tension applied by the steel cable on the steel sheet piles until the soil reaches the target height. After the filled soil is consolidated and settled in the underwater environment, the water enclosed by the retaining wall is pumped out to reveal the underwater foundation as a dry land construction working surface.

[0007] In one embodiment, after sequentially untying two steel cables fixed to hooks of two rows of water retaining walls, connecting the free ends of the two steel cables to each other via a rope adapter, operating a winch to tension the steel cables so that the connected steel cables can apply a first horizontal tensioning force directed toward the water retaining wall through a fixed pulley to enhance the ability of the water retaining wall to resist lateral deformation, and through underwater synchronous monitoring of the water retaining wall, regulating in real time the intensity of the first horizontal tensioning force and filling soil in the space between the two rows of water retaining walls, and during the soil filling process, synchronously operating the winch to dynamically adjust the tensioning force applied by the steel cables to the steel sheet piles according to the soil filling height and the deformation of the steel sheet piles until the soil reaches a target height, the method further includes: A pull rod is installed on the two rows of retaining walls to apply a second horizontal tensioning force directed toward the retaining walls. The pull rod is located above the fixed pulley so that the pull rod and the fixed pulley form a vertically linked constraint system on the retaining wall.

[0008] In one embodiment, after the filled soil material is consolidated and settled in the underwater environment, before the method of pumping out the water enclosed by the retaining wall to expose the underwater foundation as a dry land construction working surface, the method further includes: A wall weir is set up on the retaining wall, and the height of the wall weir is higher than the height of the retaining wall.

[0009] In one embodiment, after the filled soil material consolidates and settles in the underwater environment, the water enclosed by the retaining wall is pumped out to reveal the underwater foundation as a dry land construction working surface, and then the retaining wall needs to be dismantled, specifically including: Remove the soil between two rows of retaining walls in a layered manner and test the stability of the retaining walls after completing each layer of removal; Control the water level difference between the inner and outer sides of the two rows of retaining walls; removing the tie rods on the two rows of water retaining walls to release the second horizontal tensioning force exerted by the tie rods on the two rows of water retaining walls; operating the winch to release the first horizontal tension applied by the steel cable on the two rows of water retaining walls; Remove the rope adapter from the steel cable and hang the two steel cables on the hooks of the corresponding steel sheet piles; The steel sheet piles on the underwater foundation are pulled out and the pulled out steel sheet piles are recycled.

[0010] In one embodiment, the method of removing soil between two rows of retaining walls in a layered manner and testing the stability of the retaining walls after completing the removal of each layer further includes: When removing soil in layers, the thickness of each layer removed shall be ≤2m.

[0011] In one embodiment, the method for controlling the water level difference between the inner and outer sides of two rows of water retaining walls further includes: The internal and external water level difference of the two rows of retaining walls is controlled at ≤0.5m.

[0012] In one embodiment, the method of removing the tie rods from the two rows of water retaining walls to release the second horizontal tensioning force applied by the tie rods on the two rows of water retaining walls further includes: The preload force applied by the tie rods to the two rows of water retaining walls is released in a step-by-step manner, and the unloading interval at each level is ≥ 2h. The deformation of the water retaining wall is monitored simultaneously. After the water retaining wall tends to be stable, the preload force applied by the tie rods to the water retaining wall continues to be released step by step until the tie rods are removed from the water retaining wall.

[0013] In one embodiment, a method for removing steel sheet piles from an underwater foundation and recycling the removed steel sheet piles comprises: Remove the steel sheet piles in the retaining wall and vibrate them in a cycle for 30 seconds before removing the target steel sheet piles, with a vibration interval of two minutes; After successfully extracting the steel sheet piles from the underwater foundation, high-pressure water is used to remove any debris from the surface of the steel sheet piles.

[0014] In one embodiment, the method of removing steel sheet piles on an underwater foundation and recycling the removed steel sheet piles further includes: Separate debris from steel sheet piles; The steel cables are subjected to non-destructive testing and stress relaxation testing, and are coded and stored for future use after meeting the standards.

[0015] Compared to existing technologies, the construction method for a double-row steel sheet pile cofferdam proposed in the above-mentioned technical solution introduces a tensioning constraint system consisting of a winch, fixed pulley, steel cable, and rope connector between the two rows of retaining walls. This system creates an active force-bearing system independent of foundation stiffness, significantly improving the cofferdam's overall deformation resistance and structural stability. Specifically, through the coordination of the steel cable and fixed pulley, the tension applied by the winch above the water surface is converted into a first horizontal tensioning force acting on the underwater retaining wall, thereby forming an active tensioning constraint between the two rows of steel sheet piles. This first tensioning force can be dynamically adjusted based on the filling progress and wall deformation, achieving real-time reinforcement of the retaining wall, either locally or as a whole, and effectively preventing "kick-up" deformation and instability caused by increased internal soil pressure. Compared to traditional methods that rely on passive foundation resistance, this solution overcomes the limitations of structural stability, enabling the cofferdam to adapt to engineering requirements of higher water heads and greater depths. The winch realizes the continuous adjustment function of the steel cable tension, and can adjust the restraining force in real time according to the actual deformation during the soil filling process, ensuring that the cofferdam structure is always in the optimal stress state. This dynamic adjustment mechanism makes the cofferdam more adaptable and fault-tolerant when dealing with different geological conditions, hydrological changes and construction disturbances, which helps to reduce construction risks and improve project quality. Because traditional cofferdam structures mainly rely on the depth of the pile body embedded in the foundation to resist lateral deformation, they often require longer steel sheet piles and higher construction investment. However, the application of the active tensioning system in this application effectively reduces the reliance on the passive resistance of the foundation, thereby appropriately shortening the insertion depth of the steel sheet piles, reducing material consumption and construction costs. At the same time, this technical solution does not require additional complex reinforcement measures such as riprap back pressure or cement mixing piles, further simplifying the construction process and saving time and economic investment. The active constraint structure proposed in this application is particularly suitable for soft soil foundations or strata with low bearing capacity, making up for the defect that traditional cofferdams are difficult to implement tall structures under such geological conditions. By replacing part of the foundation support function with an external tensioning system, it becomes possible to build high-head cofferdams in soft soil areas, broadening the application scenarios of double-row steel sheet pile cofferdams. It is particularly suitable for complex water-related projects such as dam foundations, deep-water bridge foundations, port expansions, and coastal flood control projects.

[0016] To sum up, the present application provides a double-row steel sheet pile cofferdam body and its construction method with reasonable structure, convenient operation, high safety and strong economy, which effectively solves the problem of insufficient lateral deformation resistance of retaining walls in the existing technology, has good engineering application prospects and social and economic benefits, and is of great significance for promoting the technological progress of cofferdam engineering and the development of water engineering construction.

[0017] The above summary is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments and features described above, further aspects, embodiments and features of the present application will be readily apparent by reference to the accompanying drawings and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar components or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in this application and should not be construed as limiting the scope of this application.

[0019] Figure 1 This is a schematic diagram of the three-dimensional structure of the cofferdam body composed of double rows of steel sheet piles in an embodiment of the present application; Figure 2 for Figure 1 A magnified view of part A; Figure 3 for Figure 1 A magnified view of part B; Figure 4 for Figure 1 Magnified view of part C; Figure 5 This is a distribution diagram of the pull rods on the retaining wall in the embodiment of this application; Figure 6 This is a distribution diagram of the steel cables in the retaining wall in the embodiment of this application; Figure 7 This is an enlarged view of the structure of the first pile body and the winch in the embodiment of the present application; Figure 8 This is an enlarged structural diagram of the first pile body and the fixed pulley in the embodiment of the present application; Figure 9 This is a schematic structural diagram of the second pile body in the embodiment of the present application; Figure 10 This is a schematic structural diagram of the second pile body in an embodiment of the present application.

[0020] Reference numerals: 1. Retaining wall; 11. First pile body; 12. Second pile body; 111, bottom plate; 112, rib plate; 113, wing plate; 114, first connecting buckle; 121, pile plate body; 122, second connecting buckle; 2. Winch; 21. Reel; 22. Check wheel; 23. Locking component; 3. Fixed pulley; 31. Mounting lug; 32. Pulley; 320. Slideway; 4. Steel cable; 41. First tensioning portion; 42. Second tensioning portion; 5. Hook; 6. Rope connector; 7. Pull rod; 8. Earth materials; 9. Weir on the wall. DETAILED DESCRIPTION

[0021] Hereinafter, only certain exemplary embodiments are briefly described. As will be appreciated by those skilled in the art, the described embodiments may be modified in various ways without departing from the spirit or scope of the present application. Therefore, the drawings and description are to be regarded as illustrative in nature and not restrictive.

[0022] Reference Figure 1 As shown, in the embodiment of the present application, a construction method of a double-row steel sheet pile cofferdam is proposed, and the construction method of the double-row steel sheet pile cofferdam may include: Hooks 5, winches 2 with steel cables 4 wound around them, and fixed pulleys 3 for guiding the extension of the steel cables 4 are arranged at intervals along the height direction of the steel sheet piles. The steel cables 4 drawn out from the winches 2 are passed around the fixed pulleys 3, and the free ends of the steel cables 4 are connected to the hooks 5. The steel sheet piles are driven into the underwater foundation to form two rows of spaced-apart retaining walls 1. The hooks 5, winches 2, and fixed pulleys 3 are respectively located on the opposite sides of the two rows of retaining walls 1, and the fixed pulleys 3 are located below the corresponding winches 2. The two steel cables 4 fixed on the hooks 5 of the two rows of water retaining walls 1 are untied in turn, and the free ends of the two steel cables 4 are connected to each other through a rope adapter. The winch 2 is operated to tension the steel cables 4 so that the connected steel cables 4 can apply a first horizontal tensioning force directed to the water retaining wall 1 through the fixed pulley 3 to enhance the ability of the water retaining wall 1 to resist lateral deformation. The strength of the first horizontal tensioning force can be adjusted in real time through underwater synchronous monitoring of the water retaining wall 1.

[0023] A pull rod 7 is installed on the two rows of water retaining walls 1. The pull rod 7 applies a second horizontal tensioning force directed toward the water retaining wall 1. The pull rod 7 is located above the fixed pulley 3 so that the pull rod 7 and the fixed pulley 3 form a vertically linked constraint system on the water retaining wall 1.

[0024] The coordinated application of tension by the pull rod 7 and the steel cable 4 not only enhances the coordinated force-bearing capacity of the retaining wall at different heights, but also further improves the overall rigidity and stability of the cofferdam, avoiding unnecessary damage caused by localized uneven force. The tensioning mechanism employed in the construction method of this application provides a more reliable protection for cofferdam construction in complex underwater environments.

[0025] Specifically, the technical solution adopted in this application utilizes the construction method of this embodiment, forming an active force-bearing system through the vertical linkage constraint of the steel cable 4 and the pull rod 7. This changes the traditional cofferdam construction's over-reliance on foundation stiffness and improves the feasibility of building a cofferdam of a certain height on soft soil foundations. Secondly, with the cooperation of the steel cable 4 and the fixed pulley 3, the preload applied by the steel cable 4 to the retaining wall 1 is adjusted by the winch 2, dynamically adjusting the restraining force according to the filling progress. Furthermore, during the construction process, the retaining wall 1's ability to resist lateral deformation is enhanced without complex and expensive reinforcement measures. Since cofferdam construction generally relies on the passive resistance of the foundation to limit its deformation, a larger portion of the pile is embedded in the foundation to resist lateral deformation. The technical solution proposed in this application, by coordinating the steel cable 4 and the fixed pulley 3 to achieve underwater tensioning, effectively enhances the lateral stiffness of the retaining wall 1, reduces its reliance on the passive resistance of the foundation, and thus shortens the depth of the pile insertion into the foundation, saving construction materials and investment.

[0026] The space between the two rows of retaining walls 1 is filled with soil 8. During the filling process, the winch 2 is synchronously operated to dynamically adjust the tension applied by the steel cable 4 to the steel sheet piles according to the filling height of the soil 8 and the deformation of the steel sheet piles until the soil 8 reaches the target height. After the filled soil material 8 is consolidated and settled in the underwater environment, the water surrounded by the water retaining wall 1 is pumped out to reveal the underwater foundation as a dry land construction working surface.

[0027] Specifically, in the technical solution adopted in this application, this construction method has clear practicality in terms of cofferdam engineering applications. For example, when constructing in soft foundation areas, by calculating the embedment depth of the pile and the preload parameters, the tension of the steel cable 4 and the filling of the soil 8 can be simultaneously promoted. During the construction process, the tension constraint system of the steel cable 4 and the pull rod 7, which are linked vertically, ensures balanced force on the retaining wall 1. The combination of layered control and real-time monitoring during the filling stage can further ensure the safety of the retaining wall 1 structure during construction. It should be noted that the technical solution of the present application is mainly able to address the problem that piles in traditional cofferdams are prone to lateral deformation under soft soil foundation conditions, thereby providing a structure that can pull the double-row retaining wall 1 under the pile body, and can adjust the tension of the underwater structure on the water, thus breaking through the passive dependence of the traumatic cofferdam on the foundation stiffness. After the tension force is dynamically adjusted according to the filling conditions of the soil material 8 and the deformation state of the pile body, it can better adapt to the lateral stress applied to the retaining wall 1 and constantly changing, optimize the stiffness requirements of the cofferdam construction, and reduce the need for the pile body to be embedded. The depth of the pile into the foundation can significantly reduce the dependence of the pile on the foundation limit while ensuring the stability of the cofferdam, improve the precise control of the pile body against lateral deformation, effectively expand the scope of application of the cofferdam project, and provide a new solution for the cofferdam project under complex geological conditions, which significantly improves the practical value of the cofferdam project. Compared with the traditional technology of strengthening the rigid properties of the foundation through concrete and auxiliary reinforcement of the outer side of the retaining wall 1 by blowing sea sand, the construction method proposed in this application can save nearly hundreds of millions of engineering costs and has achieved great success in commercial engineering.

[0028] Before the water enclosed by the water retaining wall 1 is pumped out, a wall weir 9 may be set up on the water retaining wall 1 . The height of the wall weir 9 is higher than that of the water retaining wall 1 .

[0029] Specifically, in the technical solution adopted in this application, the weir 9 on the wall can further play a role in blocking water and protecting against waves. When the retaining wall 1 is close to the target height, the weir 9 on the wall can be used to make up for the remaining required height of the retaining wall 1, so as to achieve the purpose of saving project investment costs.

[0030] After completing the required dry land construction work, it is necessary to dismantle the constructed retaining wall 1, which can be specifically carried out according to the following steps: The soil 8 between the two rows of retaining walls 1 is removed in a layered manner, and the stability of the retaining wall 1 is tested after each layer of removal is completed; when removing in a layered manner, the thickness of each layer of soil 8 removed is ≤2m.

[0031] Control the water level difference between the inner and outer sides of the two rows of water retaining walls 1; the water level difference between the inner and outer sides of the two rows of water retaining walls 1 is controlled to be ≤0.5m.

[0032] Removing the tie rods 7 on the two rows of water retaining walls 1 to release the second horizontal tensioning force exerted by the tie rods 7 on the two rows of water retaining walls 1; The pre-tightening force applied by the tie rod 7 to the two rows of water retaining walls 1 is released in a step-by-step manner, and the unloading interval at each level is ≥ 2h, and the deformation of the water retaining wall 1 is monitored synchronously. After the water retaining wall 1 tends to be stable, the pre-tightening force applied by the tie rod 7 to the water retaining wall 1 continues to be released step by step until the tie rod 7 is removed from the water retaining wall 1.

[0033] Operating the winch 2 to release the first horizontal tension applied by the steel cable 4 on the two rows of water retaining walls 1; Remove the rope adapters on the steel cables 4 and hang the two steel cables 4 on the hooks 5 of the corresponding steel sheet piles; The steel sheet piles on the underwater foundation are pulled out and the pulled out steel sheet piles are recycled.

[0034] Remove the steel sheet piles in the retaining wall 1 and vibrate them cyclically for 30 seconds before removing the target steel sheet piles, with a vibration interval of two minutes; After successfully extracting the steel sheet piles from the underwater foundation, high-pressure water is used to remove any debris from the surface of the steel sheet piles.

[0035] Separate debris from steel sheet piles; The steel cable 4 is subjected to non-destructive testing and stress relaxation testing, and after meeting the standards, it is coded and stored for future use.

[0036] Specifically, the technical solution proposed in this application addresses the technical difficulties faced by traditional double-row steel sheet pile cofferdams in soft soil construction by providing an underwater adjustable tensioning solution. This solution, through the unique coordinated structure of steel cables (4) and fixed pulleys (3), fundamentally changes the cofferdam's force-bearing mechanism, overcoming the technical problem of insufficient localized lateral stress resistance of the retaining wall (1) in existing cofferdams. By addressing the technical challenge of uncontrollable localized outward deformation on soft soil, the proposed construction method enables higher water heads and complex cofferdam conditions for double-row steel sheet pile cofferdams, overcoming the application limitations of this technology in major projects such as cross-sea bridges and deep-water ports. Compared to traditional riprap prevention, this solution can save a significant amount of stone and stone transportation costs. Because the pile body utilizes a steel structure and can control its lateral deformation during use, allowing for reuse, this increases pile recovery rates, further reduces material costs, and meets green construction requirements. The technical solution of this application reduces the workload and expense of foundation treatment, eliminating the need for large riprap vessels and cement mixing equipment during construction, significantly reducing project costs. Regarding construction quality, the ability to dynamically adjust the tension on the retaining wall 1 to resist lateral deformation improves construction quality and the reliability of the retaining wall 1, simplifies the construction process, and increases construction efficiency. By reducing or even eliminating the need for riprap and concrete filling to alter the foundation geology, disturbances to the riverbed ecology are minimized.

[0037] It should be explained that the essential difference between this application and traditional technologies lies in the change in the force mode in which the retaining wall 1 responds to the lateral stress applied by the soil 8, thereby optimizing the traditional passive resistance to active control in a tension mode, and then optimizing the fixed support to dynamic adjustment of the tension force. This optimizes the building that completely relies on the foundation to restrain its resistance to lateral stress, so that it can resist the lateral stress applied by the soil 8 on the retaining wall 1 through its own structure. This makes the cofferdam construction no longer dependent on the rigid properties of the foundation geology, making it possible to build the cofferdam body on soft soil foundations such as silt, expanding the application range of cofferdam projects and providing a more economical and reliable solution for major engineering construction.

[0038] In order to implement the construction method in the above embodiment, refer to Figures 1 to 10As shown, the present application proposes a cofferdam body composed of double rows of steel sheet piles, which may include: two rows of water retaining walls 1, which are arranged at intervals on an underwater foundation; a winch 2, which is arranged on each water retaining wall 1; a fixed pulley 3, which is arranged on each water retaining wall 1, the fixed pulley 3 and the winch 2 are arranged along the height direction of the water retaining wall 1, and the fixed pulley 3 is located below the winch 2; a steel cable 4, which is wound around the winch 2, and the free end of the steel cable 4 is led out from the winch 2 and passes around the fixed pulley 3; and a rope connector 6, wherein the two steel cables 4 passing around the corresponding fixed pulleys 3 are connected by the rope connector 6, thereby dividing the steel cable 4 into a first tensioning portion 41 and a second tensioning portion 42, the first tensioning portion 41 being located between the winch 2 and the fixed pulley 3, and the second tensioning portion 42 being located between the fixed pulley 3 and the rope connector 6; When the winch 2 is rotated to tension the steel cable 4 , the first tensioning portion 41 drives the second tensioning portion 42 via the fixed pulley 3 to apply a first horizontal tensioning force directed toward the corresponding water retaining wall 1 .

[0039] Specifically, in the technical solution adopted in the present application, the winch 2 can be set above the water surface and the fixed pulley 3 can be set in the water, so that the steel cable 4 is led out of the winch 2, passes around the fixed pulley 3 and is connected through the rope connector 6. During use, after the winch 2 is rotated and adjusted to tension the steel cable 4, a first tensioning portion 41 and a second tensioning portion 42 can be formed on the steel cable 4. The first tensioning portion 41 is located between the winch 2 and the fixed pulley 3 and extends along the height direction of the water retaining wall 1. The second tensioning portion 42 is located between the fixed pulley 3 and the rope connector 6 and extends along the spacing direction between the two rows of water retaining walls 1, so that the second tensioning portion 42 changes direction through the fixed pulley 3, thereby applying a first horizontal tensioning force directed to the two rows of water retaining walls 1, thereby increasing the ability of the two rows of water retaining walls 1 to resist lateral deformation. In this embodiment, the ability of the two rows of water retaining walls 1 near the fixed pulley 3 to resist lateral deformation is specifically enhanced, so that the ability of the underwater water retaining wall 1 to resist lateral deformation can be dynamically adjusted through the winch 2; when in use, the winch 2 can be continuously rotated according to the degree of deformation of the water retaining wall 1 to increase the first tensioning force applied by the second tensioning part 42 to the water retaining wall 1 through the fixed pulley 3.

[0040] Further, refer to Figure 2 As shown, in some embodiments, it also includes: a hook 5, which is arranged on the retaining wall 1 and located above the fixed pulley 3. The free end of the steel cable 4 can be temporarily hung on the hook 5 after passing around the fixed pulley 3.

[0041] Specifically, in the technical solution adopted in this application, before the water retaining wall 1 is driven into the underwater foundation, the free end of the steel cable 4 that has passed through the fixed pulley 3 can be temporarily hung on the hook 5 to avoid prematurely forming a first tension force on the two rows of water retaining walls 1 and affecting the normal piling operation on the underwater foundation. After the piling is completed, the free end of the steel cable 4 can be separated from the hook 5, and the free ends of the two steel cables 4 can be connected via the rope connector 6; or when the water retaining wall 1 needs to be dismantled, the rope connector 6 can be released and the free ends of the two steel cables 4 can be hung on the corresponding hook 5 again, which can effectively prevent the steel cables 4 from being out of control and affecting the construction operation of dismantling the water retaining wall 1.

[0042] Further, refer to Figure 1 and Figure 5 As shown, in some embodiments, it also includes: a pull rod 7 connected between the two rows of water retaining walls 1 to apply a second horizontal tensioning force directed to the two rows of water retaining walls 1, and the pull rod 7 is located above the fixed pulley 3.

[0043] Specifically, in the technical solution adopted in the present application, pull rods 7 are arranged at positions close to the water surface of the two rows of water retaining walls 1. The two rows of water retaining walls 1 cooperate with the second tensioning portion 42 of the steel cable 4 through the pulling of the pull rods 7, and can form a second horizontal tensioning force on the two rows of water retaining walls 1 that is linked up and down with the first horizontal tensioning force, thereby further enhancing the ability of the two rows of water retaining walls 1 to resist lateral deformation, so that when soil 8 is filled between the two rows of water retaining walls 1, the water retaining walls 1 can better resist the lateral pressure exerted by the soil 8 consolidated and settled in the water.

[0044] Further, refer to Figures 5 to 8 As shown, in some embodiments, the retaining wall 1 includes: a first pile body 11, having a bottom plate 111 and two ribs 112 and two wing plates 113 connected to the bottom plate 111; the two ribs 112 are arranged opposite to each other on one side surface of the bottom plate 111, and the winch 2 is rotatably configured on the two ribs 112; the two wing plates 113 are connected to the bottom plate 111 through the corresponding ribs 112, and the wing plates 113 extend toward the bottom plate 111 away from the ribs 112, and the wing plates 113 are provided with first connecting buckles 114 that can be connected to each other at the outer edges away from the bottom plate 111.

[0045] In some embodiments, the thickness of the bottom plate 111 is greater than the thickness of the ribs 112 and the wing plates 113 . The fixed pulley 3 is mounted on the bottom plate 111 , and the fixed pulley 3 is located between the two ribs 112 .

[0046] Specifically, in the technical solution adopted in the present application, the water retaining wall 1 can be composed of several pile bodies 11 connected side by side. The first pile body 11 adopts a steel structure and has a bottom plate 111 and two ribs 112 and two wing plates 113 connected to the bottom plate 111. The two ribs 112 are arranged on one side surface of the bottom plate 111 for rotatably configuring the winch 2. A fixed pulley 3 is configured on one side surface of the bottom plate 111 connected to the ribs 112. Since the bottom plate 111 needs to withstand the first horizontal tension applied by the steel cable 4 through the fixed pulley 3, the thickness of the bottom plate 111 is higher than the thickness of the ribs 112 and the wing plates 113; it can be understood that when manufacturing the first pile body 11, the bottom plate 111 needs to be thickened. The wing plate 113 is connected to the bottom plate 111 through the ribs 112, is located on both sides of the two ribs 112, and extends toward the bottom plate 111 away from the ribs 112. A first connecting buckle 114 is provided on the outer edge of the bottom plate 111 of the principle of the wing plate 113. When a water retaining wall 1 is formed by a plurality of first piles 11, two adjacent first piles 11 can be connected by the first connecting buckle 114, and after the two first piles 11 are connected by the first connecting buckle 114, there is a water retaining function between the two first piles 11.

[0047] In one embodiment, the first connecting buckle 114 can be a spirally bent outer edge of the wing plate 113 to form a vortex-type connecting buckle that can be interlocked, so that after a first pile body 11 is driven into the underwater foundation, the next first pile body 11 can connect the top and bottom of the two first pile bodies 11 through the first connecting buckle 114, and then slide the second first pile body 11 downward until it is driven into the underwater foundation, so that the two first pile bodies 11 can be connected through the first connecting buckle 114.

[0048] Further, refer to Figure 5 、 Figure 6 、 Figure 9 as well as Figure 10 As shown, in some embodiments, the retaining wall 1 also includes: a second pile body 12, having a pile plate body 121 and a second connecting buckle 122; the pile plate body 121 has a bent structure; the second connecting buckle 122 is arranged on the outer edges of both sides of the pile plate body 121, and the second connecting buckle 122 is used to connect the first connecting buckle 114.

[0049] Specifically, in the technical solution adopted in this application, two adjacent first pile bodies 11 can also be connected by a plurality of second pile bodies 12. The second pile body 12 also adopts a steel structure. The second pile body 12 has a pile plate body 121. For details, please refer to Figure 9 and Figure 10As shown, the pile plate body 121 can adopt a bent structure or an arc structure so that when connecting the first pile body 11, it can have better plasticity to adapt to the first pile body 11 that has been inserted, thereby cooperating with the first pile body 11 to resist water. Second connecting buckles 122 that can be connected to the first connecting buckle 114 are provided on both sides of the outer edge of the pile plate body 121. The second connecting buckle 122 adopts the same structure as the first connecting port, so it will not be repeated.

[0050] It should be noted that since the structure of the second pile body 12 is simpler than that of the first pile body 11, the manufacturing cost of the second pile body 12 is much lower than that of the first pile body 11. When there is no need to install more winches 2 and fixed pulleys 3 on the retaining wall 1, the second pile body 12 can be used to replace the first pile body 11, thereby achieving the purpose of saving the construction cost of the cofferdam body.

[0051] Further, refer to Figure 2 and Figure 7 As shown, in some embodiments, the winch 2 includes: a drum 21, which is rotatably arranged between two ribs 112; a check wheel 22, which is sleeved on the drum 21, and the check wheel 22 rotates synchronously with the drum 21, and a plurality of locking teeth are arranged circumferentially on the check wheel 22; a locking component 23, which is installed on the rib 112 close to the check wheel 22, and the locking component 23 is used to be obliquely supported between two adjacent locking teeth, so that the locking component 23 can prevent the drum 21 from rotating in the clockwise direction or counterclockwise direction on the rib 112.

[0052] Specifically, in the technical solution adopted in the present application, since the check wheel 22 is sleeved on the reel 21 and the check wheel 22 rotates synchronously with the reel 21, when the locking component 23 abuts against the check wheel 22 in an inclined supporting manner, the check wheel 22 can limit the reel 21 from rotating in one direction without affecting the rotation in the other direction; taking the clockwise and counterclockwise directions through the rib 112 as an example, when the locking component 23 is obliquely supported on the locking teeth on the check wheel 22, when the reel 21 rotates in the clockwise direction of the rib 112 and conforms to the supporting direction of the locking component 23, the locking component 23 does not affect the normal rotation of the reel 21; on the contrary, when the reel 21 rotates in the counterclockwise direction of the rib 112, the locking component 23 forms a supporting force between the rib 112 and the locking teeth to prevent the reel 21 from rotating in the counterclockwise direction of the rib 112. For example, the clockwise rotation of the drum 21 along the rib plate 112 is set to collect the steel cable 4, while the counterclockwise rotation of the drum 21 along the rib plate 112 is set to lead out the steel cable 4, so that when the tensioning force applied to the first pile body 11 by the steel cable 4 is adjusted by rotating the drum 21, the cooperation of the check wheel 22 and the locking component 23 can effectively prevent the drum 21 from returning to its original position and causing the tensioning force on the steel cable 4 to fail.

[0053] Further, refer to Figure 3 and Figure 8 As shown, in some embodiments, the fixed pulley 3 includes: two mounting ears 31, which are fixed on one side surface of the base plate 111, and the two mounting ears 31 are arranged opposite to each other; a pulley member 32, which is rotatably configured on the two mounting ears 31, and the pulley member 32 is provided with a slide groove 320 along the circumferential direction, and the slide groove 320 is used to fit the radial side of the steel cable 4.

[0054] Specifically, in the technical solution adopted in the present application, in order to realize the configuration of the fixed pulley 3 on the first pile body 11, two oppositely arranged mounting lugs 31 can be installed on the thickened base plate 111, and the pulley member 32 can be rotatably configured on the two mounting lugs 31, so that the friction of the steel cable 4 during the change of direction and the adjustment of the tension can be reduced by the rotatable pulley member 32. In one embodiment, in order to prevent the steel cable 4 from generating lateral friction on the pulley member 32, a sliding groove 320 is provided on the radial side of the pulley member 32. When the steel cable 4 passes around the fixed pulley 3, the steel cable 4 can be embedded in the sliding groove 320 of the pulley member 32, so that the steel cable 4 can slide in the sliding groove 320 during the process of adjusting the tension, which can effectively prevent the steel cable 4 from being misaligned and generating unnecessary lateral friction on the pulley member 32, thereby reducing the friction loss of the steel cable 4 and improving the service life of the steel cable 4.

[0055] In the description of this specification, the reference terms "one embodiment," "some embodiments," "example," "specific example," or "some examples" mean that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. Moreover, the specific features, structures, materials, or characteristics described may be combined in any appropriate manner in any one or more embodiments or examples. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification, as well as features of different embodiments or examples, unless they are mutually inconsistent.

[0056] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0057] Any process or method description in a flow chart or otherwise described herein can be understood to represent a module, segment or portion of code comprising one or more executable instructions for implementing the steps of a specific logical function or process. The scope of the preferred embodiments of the present application includes additional implementations in which the functions may be performed in a different order than shown or discussed, including in a substantially simultaneous manner or in a reverse order depending on the functions involved.

[0058] The logic and / or steps represented in the flowchart or otherwise described herein may be considered, for example, as a sequenced list of executable instructions for implementing the logical functions, and may be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device).

[0059] It should be understood that various parts of the present application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. All or part of the steps of the above embodiment method can be completed by instructing the relevant hardware through a program, which can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiment.

[0060] In addition, the functional units in the various embodiments of the present application may be integrated into a single processing module, or each unit may exist physically separately, or two or more units may be integrated into a single module. The aforementioned integrated modules may be implemented in the form of hardware or in the form of software functional modules. If the aforementioned integrated modules are implemented in the form of software functional modules and sold or used as independent products, they may also be stored in a computer-readable storage medium. The storage medium may be a read-only memory, a magnetic disk, or an optical disk, etc.

[0061] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any person skilled in the art can easily conceive of various modifications or substitutions within the technical scope disclosed in this application, and such modifications or substitutions should be included within the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A construction method for a double-row steel sheet pile cofferdam, characterized in that: include: Hooks, winches wound with steel cables, and fixed pulleys for guiding the extension direction of the steel cables are arranged at intervals on the steel sheet piles along the height direction thereof; the steel cables drawn out from the winches are passed around the fixed pulleys, and the free ends of the steel cables are connected to the hooks; The steel sheet piles are driven into the underwater foundation to form two rows of spaced-apart retaining walls, the hooks, the winches, and the fixed pulleys are respectively located on opposite sides of the two rows of retaining walls, and the fixed pulleys are located below the corresponding winches; The two steel cables fixed on the hooks of the two rows of water retaining walls are untied in sequence, and the free ends of the two steel cables are connected to each other through a rope adapter. The winch is operated to tension the steel cables so that the connected steel cables can apply a first horizontal tensioning force directed to the water retaining wall through the fixed pulley to enhance the ability of the water retaining wall to resist lateral deformation. The strength of the first horizontal tensioning force is regulated in real time through underwater synchronous monitoring of the water retaining wall.

2. The construction method of double-row steel sheet pile cofferdam according to claim 1, characterized in that: After sequentially untying the two steel cables fixed to the hooks of the two rows of water retaining walls, connecting the free ends of the two steel cables to each other through a rope adapter, operating the winch to tension the steel cables so that the connected steel cables can apply a first horizontal tensioning force directed toward the water retaining wall through the fixed pulley to enhance the ability of the water retaining wall to resist lateral deformation, and regulating the intensity of the first horizontal tensioning force in real time through underwater synchronous monitoring of the water retaining wall, the method further includes: Filling soil in the space between the two rows of retaining walls, and during the soil filling process, synchronously operating the winch to dynamically adjust the tensioning force applied by the steel cable to the steel sheet piles according to the soil filling height and the deformation of the steel sheet piles until the soil reaches the target height; After the filled soil material is consolidated and settled in the underwater environment, the water surrounded by the retaining wall is pumped out to expose the underwater foundation as a dry land construction working surface.

3. The construction method of double-row steel sheet pile cofferdam according to claim 2, characterized in that: The method further comprises the following steps: untying the two steel cables fixed to the hooks of the two rows of water retaining walls in sequence, connecting the free ends of the two steel cables to each other through a rope adapter, operating the winch to tension the steel cables so that the connected steel cables can apply a first horizontal tensioning force directed to the water retaining wall through the fixed pulley to enhance the ability of the water retaining wall to resist lateral deformation; and regulating the intensity of the first horizontal tensioning force and the filling of soil in the space between the two rows of water retaining walls in real time through underwater synchronous monitoring of the water retaining wall. During the soil filling process, the method further comprises: A pull rod is installed on the two rows of retaining walls, and the pull rod applies a second horizontal tensioning force directed toward the retaining wall. The pull rod is located above the fixed pulley so that the pull rod and the fixed pulley form a vertically linked constraint system on the retaining wall.

4. The construction method of double-row steel sheet pile cofferdam according to claim 2, characterized in that: After the filled soil material is consolidated and settled in the underwater environment, before the method of pumping out the water enclosed by the retaining wall to expose the underwater foundation as a dry land construction working surface, the method further includes: A wall weir is set up on the retaining wall, and the height of the wall weir is higher than the height of the retaining wall.

5. The construction method of double-row steel sheet pile cofferdam according to claim 3, characterized in that: After the filled soil material is consolidated and settled in the underwater environment, the water enclosed by the retaining wall is pumped out to reveal the underwater foundation as a dry land construction working surface. The retaining wall needs to be dismantled, which specifically includes: Removing soil between two rows of retaining walls in a layered manner, and testing the stability of the retaining walls after completing the removal of each layer; Controlling the water level difference between the inner and outer sides of the two rows of retaining walls; Removing the tie rods on the two rows of retaining walls to release the second horizontal tensioning force applied by the tie rods on the two rows of retaining walls; operating the winch to release the first horizontal tension applied by the steel cable on the two rows of retaining walls; Remove the rope adapter on the steel cable and hang the two steel cables on the hooks corresponding to the steel sheet piles; The steel sheet piles are pulled out from the underwater foundation and the pulled out steel sheet piles are recycled.

6. The construction method of double-row steel sheet pile cofferdam according to claim 5, characterized in that: The method of removing soil between two rows of retaining walls in a layered manner and testing the stability of the retaining wall after completing the removal of each layer also includes: When removing the soil in a layered manner, the thickness of each layer of soil removed is ≤2m.

7. The construction method of double-row steel sheet pile cofferdam according to claim 5, characterized in that: The method for controlling the water level difference between the inner and outer sides of the two rows of retaining walls further includes: The difference in water level between the inside and outside of the two rows of retaining walls is controlled to be ≤0.5m.

8. The construction method of double-row steel sheet pile cofferdam according to claim 5, characterized in that: The method of removing the tie rods from the two rows of water retaining walls to release the second horizontal tensioning force applied by the tie rods on the two rows of water retaining walls further includes: The pre-tightening force applied by the tie rod to the two rows of the water retaining walls is released in a step-by-step manner, and the unloading interval at each level is ≥ 2h, and the deformation of the water retaining walls is monitored synchronously. After the water retaining walls tend to be stable, the pre-tightening force applied by the tie rod to the water retaining walls continues to be released step by step until the tie rod is removed from the water retaining walls.

9. The construction method of double-row steel sheet pile cofferdam according to claim 5, characterized in that: The method of removing the steel sheet piles on the underwater foundation and recycling the removed steel sheet piles includes: Pulling out the steel sheet piles in the retaining wall, and vibrating the target steel sheet piles in a cycle for 30 seconds before pulling them out, with a vibration interval of two minutes; After the steel sheet piles are successfully pulled out from the underwater foundation, high-pressure water is used to remove attachments on the surfaces of the steel sheet piles.

10. The construction method of double-row steel sheet pile cofferdam according to claim 9, characterized in that: The method of removing the steel sheet piles on the underwater foundation and recycling the removed steel sheet piles further includes: Separating debris from the steel sheet piles; The steel cables are subjected to non-destructive testing and stress relaxation testing, and are coded and stored for future use after meeting the standards.

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