Construction method of double-row steel sheet pile cofferdam

Abstract

The application provides a construction method of a double-row steel sheet pile cofferdam, which comprises the following steps: arranging hooks, winches with steel cables and fixed pulleys for guiding the extension direction of the steel cables at intervals along the height direction of the steel sheet piles; winding the steel cables led out of the winches around the fixed pulleys; and connecting the free ends of the steel cables to the hooks; driving the steel sheet piles into the underwater foundation to form two rows of water retaining walls arranged at intervals; arranging the hooks, the winches and the fixed pulleys on the opposite sides of the two rows of water retaining walls respectively, and arranging the fixed pulleys below the winches; sequentially unfastening 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, and tensioning the steel cables by operating the winches, so that the connected steel cables can exert a first horizontal tension force directed to the water retaining walls through the fixed pulleys, and the ability of the water retaining walls to resist lateral deformation is enhanced; and the technical problem of insufficient rigidity of the water retaining walls in resisting lateral stress in the main body of the double-row steel sheet pile cofferdam is solved.

Description

Technical Field

[0001] This application relates to the technical field of establishing dry construction sites in water areas, and more particularly to a construction method for a double-row steel sheet pile cofferdam. Background Technology

[0002] Double-row sheet pile cofferdams are efficient and reliable temporary water-retaining structures widely used in water-related projects such as cross-sea bridges, deep-water ports, and water conservancy projects. This structure consists of two rows of parallel sheet piles, with soil and rock or grouting material filled between them to form a composite gravity retaining wall structure. The two rows of sheet piles are firmly connected by connecting clips, which not only enhances the overall rigidity and anti-sliding capacity but also effectively improves seepage prevention performance. This structure causes minimal disturbance to the surrounding soil, has a fast construction speed, is reusable, and possesses good economic and environmental adaptability. Its main functions are to isolate water bodies, 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, making it an indispensable and important support system in current water-related engineering construction.

[0003] Despite the numerous advantages of double-row sheet pile cofferdams, certain structural stability issues remain in practical applications. As the cofferdam height increases, the lateral pressure generated by the soil on the inner side increases quadratically. When this pressure exceeds the bending capacity of the sheet piles, it easily triggers outward displacement of the pile bottom, resulting in so-called "kick-out" deformation. This deformation can lead to the instability or even collapse of the entire cofferdam, seriously threatening construction safety. Therefore, traditional double-row sheet pile cofferdams are mostly suitable for low-height, low-head engineering projects. To mitigate this problem, existing technologies typically employ two reinforcement measures: one is to fill the bottom of the outer side of the sheet piles with stones, using their self-weight to create counter-pressure and offset some of the lateral pressure; the other is to reinforce the foundation with cement-mixed piles, improving the soil's constraint on the sheet piles and enhancing overall stability.

[0004] While the aforementioned reinforcement methods have improved the deformation resistance of double-row sheet pile cofferdams to some extent, significant technical shortcomings remain. First, the rock-fill counterweight method requires a large amount of stone, resulting in high transportation and construction costs, and also occupies construction space, impacting subsequent work efficiency. Second, cement-mixed pile construction has a long cycle, especially in underwater environments where it is difficult to construct and susceptible to interference from water flow and sediment, making it difficult to control the quality of the mixed piles and guarantee the reinforcement effect. More importantly, both methods are passive reinforcement measures, only able to delay or limit the deformation trend of the sheet piles to a certain extent, but not fundamentally preventing the bending deformation caused by excessive lateral pressure. Therefore, their effectiveness in resisting lateral deformation is limited and cannot meet the actual needs of high-head, deep cofferdam projects. Therefore, there is an urgent need to develop a structural design or construction method for actively reinforcing sheet pile structures to improve the overall bearing capacity and deformation resistance of cofferdams, overcoming the limitations of existing technologies. Summary of the Invention

[0005] This application provides a construction method for a double-row steel sheet pile cofferdam to solve the technical problem of insufficient rigidity of the retaining wall in the main structure of the double-row steel sheet pile cofferdam in resisting lateral stress. The technical solution is as follows: This application provides a construction method for a double-row steel sheet pile cofferdam, including: setting hooks at intervals along the height direction on the steel sheet piles, a winch with steel cables wound around it, and a fixed pulley for guiding the extension direction of the steel cables; passing the steel cables led out from the winch around the fixed pulleys; and connecting the free end of the steel cables to the hooks. Sheet piles are driven into the underwater foundation to form two rows of spaced retaining walls. Hooks, winches, and fixed pulleys are located on the opposite sides of the two rows of retaining walls, with the fixed pulleys located below the corresponding winches. The two steel cables fixed to the hooks on the two rows of retaining walls are untied in sequence. 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 tension force to the retaining walls through the fixed pulley, thereby enhancing the retaining walls' ability to resist lateral deformation. The intensity of the first horizontal tension force is adjusted in real time by monitoring the retaining walls underwater.

[0006] In one embodiment, after sequentially untying the two steel cables fixed to the hooks on the two rows of retaining walls, connecting the free ends of the two steel cables together via a rope adapter, and operating a winch to tension the steel cables, so that the connected steel cables can apply a first horizontal tension force towards the retaining walls through a fixed pulley to enhance the retaining walls' ability to resist lateral deformation, and after the method of real-time adjustment of the intensity of the first horizontal tension force through underwater synchronous monitoring of the retaining walls, the method further includes: Soil is filled into the space between the two rows of retaining walls. During the filling process, the tension of the steel cable applied to the steel sheet pile is dynamically adjusted by operating the winch according to the filling height and the deformation of the steel sheet pile until the soil reaches the target height. After the filled soil material has consolidated and settled in the underwater environment, the water enclosed by the retaining wall is pumped out to expose the underwater foundation as a dry construction surface.

[0007] In one embodiment, the method involves sequentially untying two steel cables fixed to hooks on two rows of retaining walls, connecting the free ends of the two cables together via a rope adapter, operating a winch to tension the cables, so that the connected cables can apply a first horizontal tension force towards the retaining walls through a fixed pulley, thereby enhancing the retaining walls' ability to resist lateral deformation. The method also includes real-time adjustment of the intensity of the first horizontal tension force and the filling of soil in the space between the two rows of retaining walls through underwater synchronous monitoring of the retaining walls. During the soil filling process, the tension force applied to the sheet piles by the steel cables is dynamically adjusted synchronously by operating the winch according to the soil filling height and the deformation of the sheet piles, until the soil reaches the target height. Tie rods are installed on the two rows of retaining walls. The tie rods apply a second horizontal tension force pointing towards the retaining walls. The tie rods are located above the fixed pulleys so that the tie rods and fixed pulleys form a constraint system that links the upper and lower parts of the retaining walls.

[0008] In one embodiment, before the method of pumping out the water enclosed by the retaining wall to expose the underwater foundation as a dry construction work surface after the soil to be filled has consolidated and settled in the underwater environment, the method further includes: A wall-mounted weir is constructed on the retaining wall, with the height of the wall-mounted weir exceeding the height of the retaining wall.

[0009] In one embodiment, after the filled soil has consolidated and settled in the underwater environment, the water enclosed by the retaining wall is pumped out to expose the underwater foundation as a dry construction surface. Following this, the retaining wall also needs to be dismantled, specifically including: The soil between the two rows of retaining walls was removed in a layered manner, and the stability of the retaining walls was tested after the removal of each layer was completed. Control the water level difference between the inner and outer sides of the two rows of retaining walls; Remove the tie rods from the two rows of retaining walls to release the second horizontal tension force exerted by the tie rods on the two rows of retaining walls; Operate the winch to release the first horizontal tension force applied to the steel cable on the two rows of 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; Each sheet pile was removed from the underwater foundation, and the removed sheet piles were then recycled.

[0010] In one embodiment, the method for 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 should be ≤2m.

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

[0012] In one embodiment, the method of removing tie rods from the two rows of retaining walls to release the second horizontal tension force exerted by the tie rods on the two rows of retaining walls further includes: The preload applied to the two rows of retaining walls by the tie rods is released in a step-by-step manner, with an unloading interval of ≥2 hours between each step. The deformation of the retaining walls is monitored simultaneously. After the retaining walls stabilize, the preload applied to the retaining walls by the tie rods is released step-by-step until the tie rods are removed from the retaining walls.

[0013] In one embodiment, a method for removing sheet piles from an underwater foundation and recycling the removed sheet piles includes: Remove the sheet piles from the retaining wall, and before removing the target sheet piles, vibrate them cyclically for 30 seconds with a two-minute interval between vibrations. After successfully extracting the sheet piles from the underwater foundation, high-pressure water was used to remove any adhering substances from the surface of the sheet piles.

[0014] In one embodiment, the method for removing each sheet pile from the underwater foundation and recycling the removed sheet piles further includes: Remove debris from the sheet piles; The steel cables undergo non-destructive testing and stress relaxation testing, and are coded and stored in the database after meeting the standards.

[0015] Compared with existing technologies, the construction method of the double-row sheet pile cofferdam proposed in the above technical solution significantly improves the overall deformation resistance and structural stability of the cofferdam by introducing a tension constraint system consisting of a winch, fixed pulley, steel cable, and rope connector between the two rows of retaining walls, thus constructing an active force-bearing system without relying on the stiffness of the foundation. Specifically, through the cooperation of steel cables and fixed pulleys, the tension force applied by the winch located above the water surface is converted into a first horizontal tension force acting on the underwater retaining wall, thereby forming an active tension constraint between the two rows of sheet piles. This first tension force can be dynamically adjusted according to the filling progress and the deformation of the wall, realizing real-time reinforcement of the retaining wall locally or as a whole, effectively preventing "kick-out" deformation and instability caused by increased pressure on the inner soil. Compared with the traditional method that relies on the passive resistance of the foundation, this solution breaks through the limitations of structural stability, enabling the cofferdam to adapt to the engineering requirements of higher water heads and greater depths. By implementing continuous adjustment of the steel cable tension through a winch, the constraint force can be adjusted in real time according to the actual deformation during soil filling, ensuring that the cofferdam structure is always in an optimal stress state. This dynamic adjustment mechanism gives the cofferdam greater adaptability and fault tolerance in the face of different geological conditions, hydrological changes, and construction disturbances, helping to reduce construction risks and improve project quality. Traditional cofferdam structures mainly rely on the depth of pile embedment in the foundation to resist lateral deformation, often requiring long sheet piles and high construction costs. This application, through the application of an active tensioning system, effectively reduces the dependence on passive foundation resistance, thereby appropriately shortening the insertion depth of sheet piles and reducing material usage and construction costs. At the same time, this technical solution eliminates the need for additional complex reinforcement measures such as rockfill counterweight 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, overcoming the shortcomings of traditional cofferdams in implementing tall structures under such geological conditions. By replacing part of the foundation support function with an external tensioning system, it becomes possible to construct high-head cofferdams in soft soil areas, thus broadening the application scenarios of double-row steel sheet pile cofferdams. They are particularly suitable for complex water-related projects such as dam foundations, deep-water bridge foundations, port expansion, and coastal flood control projects.

[0016] In summary, this application provides a double-row steel sheet pile cofferdam body with reasonable structure, convenient operation, high safety and strong economy and its construction method, which effectively solves the problem of insufficient lateral deformation resistance of water-retaining walls in the prior art. It 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 overview 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 this application will become readily apparent from the accompanying drawings and the following detailed description. Attached Figure Description

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

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

[0020] Figure label: 1. Water-retaining wall; 11. First pile; 12. Second pile; 111. Base plate; 112. Rib plate; 113. Wing plate; 114. First connecting buckle; 121. Pile plate body; 122. Second connecting buckle; 2. Winch; 21. Drum; 22. Backstop wheel; 23. Locking component; 3. Fixed pulley; 31. Mounting lugs; 32. Pulley components; 320. Slide grooves; 4. Steel cable; 41. First tight section; 42. Second tight section; 5. Hooks; 6. Rope connector; 7. Pull rod; 8. Earth materials; 9. The dam on the wall. Detailed Implementation

[0021] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of this application. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0022] Reference Figure 1 As shown, an embodiment of this application proposes a construction method for a double-row steel sheet pile cofferdam, which may include: Hooks 5, winches 2 with steel cables 4 wound around them, and fixed pulleys 3 for guiding the extension direction of steel cables 4 are set at intervals along the height direction on the steel sheet pile. The steel cable 4 led out by the winch 2 is passed around the fixed pulley 3 and the free end of the steel cable 4 is connected to the hooks 5. Steel sheet piles are driven into the underwater foundation to form two rows of spaced water-retaining walls 1. Hooks 5, winches 2, and fixed pulleys 3 are located on the opposite sides of the two rows of water-retaining walls 1, and the fixed pulleys 3 are located below the corresponding winches 2. The two steel cables 4 fixed to the hooks 5 of the two rows of water-retaining walls 1 are untied in sequence. Then, the free ends of the two steel cables 4 are connected to each other through the 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 tension force to the water-retaining walls 1 through the fixed pulley 3, so as to enhance the ability of the water-retaining walls 1 to resist lateral deformation. The strength of the first horizontal tension force is adjusted in real time by underwater synchronous monitoring of the water-retaining walls 1.

[0023] Tie rods 7 are installed on the two rows of water-retaining walls 1. Tie rods 7 apply a second horizontal tension force pointing towards the water-retaining wall 1. Tie rods 7 are located above fixed pulleys 3 so that tie rods 7 and fixed pulleys 3 form a constraint system that links the upper and lower parts of the water-retaining wall 1.

[0024] After the tie rod 7 and the steel cable 4 work together to apply tension, not only is the cooperative stress-bearing capacity of the retaining wall enhanced at different heights, but the overall rigidity and stability of the cofferdam are also further improved, avoiding unnecessary damage caused by uneven local stress. The tensioning mechanism in the construction method of this application provides more reliable protection for cofferdam construction in complex underwater environments.

[0025] Specifically, in the technical solution adopted in this application, the construction method in this embodiment is used. The active force-bearing system is formed through the vertical linkage constraint of the steel cable 4 and the tie rod 7, changing the traditional cofferdam construction's over-reliance on the rigidity of the foundation and improving 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 pre-tension force applied to the retaining wall 1 by the winch 2 is adjusted to dynamically adjust the constraint force according to the filling progress. Furthermore, the ability of the retaining wall 1 to resist lateral deformation is strengthened without complex and expensive reinforcement measures during construction. Since cofferdam construction generally relies on the passive resistance of the foundation to limit deformation, most of the piles are embedded in the foundation to resist lateral deformation. However, the technical solution proposed in this application, through the underwater tension achieved by the cooperation of the steel cable 4 and the fixed pulley 3, effectively enhances the lateral stiffness of the retaining wall 1, reduces the dependence on the passive resistance of the foundation, and thus shortens the depth of the piles inserted into the foundation, saving building materials and investment funds.

[0026] Soil material 8 is filled in the space between the two rows of water-retaining walls 1. During the filling process of soil material 8, the tension force of steel cable 4 applied to steel sheet pile is dynamically adjusted by operating winch 2 according to the filling height of soil material 8 and the deformation of steel sheet pile, until soil material 8 reaches the target height. After the filled soil 8 has consolidated and settled in the underwater environment, the water enclosed by the retaining wall 1 is pumped out to expose the underwater foundation as a dry construction surface.

[0027] Specifically, in the technical solution adopted in this application, the construction method has clear practicality in the application of cofferdam engineering. For example, when constructing in areas with soft foundation soil, after calculating and determining the embedment depth of the piles and the preload parameters, the tensioning of the steel cable 4 and the filling of the soil material 8 can be advanced simultaneously. During construction, the tension constraint system of the steel cable 4 and the tie rod 7, which links the upper and lower parts, ensures the balanced force on the retaining wall 1. Furthermore, 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 is important to note that the technical solution of this application primarily addresses the problem of lateral deformation of piles in traditional cofferdams under soft soil foundation conditions. By incorporating a structure at the lower part of the piles that can tension double-row retaining walls 1, and by adjusting the tension of the underwater structure above water, this solution overcomes the passive dependence of traditional cofferdams on foundation stiffness. By dynamically adjusting the tension based on the soil filling conditions and pile deformation, it better adapts to the constantly changing lateral stress applied to the retaining walls 1, optimizing the stiffness requirements of the cofferdam structure and reducing the need for pile embedding. The depth of the piles into the foundation significantly reduces the dependence of the piles on the foundation's restraint while ensuring the stability of the cofferdam, improves the precise control of the piles' resistance to lateral deformation, effectively expands the applicable scope of cofferdam projects, provides a brand-new solution for cofferdam projects under complex geological conditions, and significantly enhances the practical value of cofferdam projects. Compared with the traditional technology of strengthening the rigidity of the foundation with concrete and using sea sand to reinforce the outside of the retaining wall 1, the construction method proposed in this application can save nearly 100 million yuan in engineering costs and has achieved great success in commercial engineering.

[0028] Before pumping out the water enclosed by the retaining wall 1, a wall weir 9 can be set up on the retaining wall 1, with the height of the wall weir 9 being higher than the height of the retaining wall 1.

[0029] Specifically, in the technical solution adopted in this application, the wall weir 9 can further play a protective role in blocking water and waves. When the water-retaining wall 1 is close to the target height, the wall weir 9 can make up for the remaining height required by the water-retaining wall 1, so as to save the project investment cost.

[0030] After completing the necessary dry site construction work, the constructed retaining wall 1 will need to be demolished, which can be carried out in the following steps: The soil material 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 the removal of each layer is completed; when removing in a layered manner, the thickness of each layer of soil material 8 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 should be controlled to be ≤0.5m.

[0032] Remove the tie rods 7 from the two rows of retaining walls 1 to release the second horizontal tension force applied by the tie rods 7 to the two rows of retaining walls 1; The preload applied to the two rows of retaining walls 1 by the tie rod 7 is released in a step-by-step manner, with an unloading interval of ≥2 hours between each step. The deformation of the retaining wall 1 is monitored simultaneously. After the retaining wall 1 becomes stable, the preload applied to the retaining wall 1 by the tie rod 7 is released step-by-step until the tie rod 7 is removed from the retaining wall 1.

[0033] Operate winch 2 to release the first horizontal tension force applied to the steel cable 4 on the two rows of retaining walls 1; Remove the rope adapter from the steel cable 4 and hang the two steel cables 4 on the hooks 5 of the corresponding steel sheet piles. Each sheet pile was removed from the underwater foundation, and the removed sheet piles were then recycled.

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

[0035] Remove debris from the sheet piles; Steel cable 4 was subjected to non-destructive testing and stress relaxation testing. After meeting the standards, it was coded and stored in the database for future use.

[0036] Specifically, the technical solution proposed in this application addresses the technical challenges of traditional double-row steel sheet pile cofferdams in soft soil foundation construction by proposing an underwater adjustable tensioning solution. This solution, through a unique combination of steel cable 4 and fixed pulley 3, fundamentally alters the cofferdam's stress mechanism, overcoming the technical problem of insufficient local resistance to lateral stress in the retaining wall 1 of existing cofferdams. Once the construction method proposed in this application solves the technical problem of uncontrollable local outward expansion deformation on soft soil foundations, it enables double-row steel sheet pile cofferdams to handle higher water heads and more complex working conditions, overcoming the application limitations of this technology in major projects such as cross-sea bridges and deep-water ports. Compared to traditional rockfill prevention, it saves a significant amount of stone and its transportation costs. Because the piles are made of steel and the degree of lateral deformation can be controlled during use, the piles can be reused, increasing the pile recovery rate, further saving material costs, and meeting green construction requirements. By adopting the technical solution of this application, the workload and cost of foundation treatment are reduced. The construction process eliminates the need for large rock-filling vessels and cement mixing pile equipment, significantly lowering project costs. Regarding construction quality, it enables dynamic adjustment of the tension force resisting lateral deformation on the retaining wall 1, improving construction quality and the reliability of the retaining wall 1, simplifying the construction process, and increasing construction efficiency. By reducing or even eliminating the need for rock-filling and concrete filling that alters the foundation geology, the disturbance to the riverbed ecosystem is minimized.

[0037] It should be explained that the essential difference between this application and traditional technologies lies in changing the stress mode of the retaining wall 1 in response to the lateral stress exerted on the soil material 8. This optimizes the traditional passive resistance into active control under a tension mode, and further optimizes the fixed support into dynamic adjustment of tension. Thus, the structure, which relied entirely on the foundation to resist lateral stress, is optimized to resist the lateral stress exerted on the retaining wall 1 by the soil material 8 through its own structure. This makes the cofferdam structure no longer dependent on the rigid properties of the foundation geology, making it possible to construct the main body of the cofferdam on soft soil foundations such as silt, expanding the application scope of cofferdam engineering, and providing a more economical and reliable solution for major engineering projects.

[0038] To implement the construction method described in the above embodiments, refer to... Figures 1 to 10As shown, this application proposes a cofferdam body composed of double-row steel sheet piles. The cofferdam body composed of double-row steel sheet piles may include: two rows of retaining walls 1, which are arranged at intervals on the underwater foundation; a winch 2, which is disposed on each retaining wall 1; a fixed pulley 3, which is disposed on each retaining wall 1, the fixed pulley 3 and the winch 2 are arranged along the height direction of the retaining wall 1, and the fixed pulley 3 is located below the winch 2; a steel cable 4, which is wound on 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, through which two steel cables 4 that pass around the corresponding fixed pulley 3 are connected, thereby dividing the steel cable 4 into a first tensioning part 41 and a second tensioning part 42, the first tensioning part 41 being located between the winch 2 and the fixed pulley 3, and the second tensioning part 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 part 41 drives the second tensioning part 42 via the fixed pulley 3 to apply a first horizontal tensioning force pointing towards the corresponding water-retaining wall 1.

[0039] Specifically, in the technical solution adopted in this application, the winch 2 can be set above the water surface and the fixed pulley 3 can be set in the water. The steel cable 4 is led out from the winch 2, passes around the fixed pulley 3, and is connected through the rope connector 6. In use, after rotating and adjusting the winch 2 to tension the steel cable 4, a first tensioning part 41 and a second tensioning part 42 can be formed on the steel cable 4. The first tensioning part 41 is located between the winch 2 and the fixed pulley 3 and extends along the height direction of the retaining wall 1. The second tensioning part 42 is located between the fixed pulley 3 and the rope connector 6 and extends along the interval direction between the two rows of retaining walls 1. The second tensioning part 42 can apply a first horizontal tensioning force pointing towards the two rows of retaining walls 1 by changing the direction of the fixed pulley 3, thereby increasing the ability of the two rows of retaining walls 1 to resist lateral deformation. In this embodiment, the ability of the two rows of water-retaining walls 1 to resist lateral deformation near the fixed pulley 3 is enhanced, so that the ability of the underwater water-retaining wall 1 to resist lateral deformation can be dynamically adjusted by the winch 2. 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 tension force applied to the water-retaining wall 1 by the second tensioning part 42 through the fixed pulley 3.

[0040] Furthermore, refer to Figure 2 As shown, in some embodiments, it also includes: a hook 5, configured on the water-retaining wall 1, located above the fixed pulley 3, and 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 retaining wall 1 is driven into the underwater foundation, the free end of the steel cable 4, which bypasses the fixed pulley 3, can be temporarily hung on the hook 5 to avoid prematurely forming the first tension on the two rows of retaining walls 1, which would affect 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 through the rope connector 6; or, when it is necessary to dismantle the retaining wall 1, 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 cable 4 from getting out of control and affecting the construction operation of dismantling the retaining wall 1.

[0042] Furthermore, refer to Figure 1 and Figure 5 As shown, in some embodiments, it further includes: a pull rod 7 connected between the two rows of water-retaining walls 1 to apply a second horizontal tension force pointing towards the two rows of water-retaining walls 1, the pull rod 7 being located above the fixed pulley 3.

[0043] Specifically, in the technical solution adopted in this application, tie rods 7 are arranged near 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 part 42 of the steel cable 4 through the counter-pull of the tie rods 7, which can form a second horizontal tension force on the two rows of water-retaining walls 1 that is linked to the first horizontal tension force, thereby further enhancing the ability of the two rows of water-retaining walls 1 to resist lateral deformation. When the soil material 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 material 8 that has solidified and settled in the water.

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

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

[0046] Specifically, in the technical solution adopted in this application, the retaining wall 1 can be composed of several piles connected side by side with the first pile 11. The first pile 11 adopts a steel structure and has a base plate 111, two ribs 112 and two wing plates 113 connecting the base plate 111. The two ribs 112 are arranged on one side surface of the base plate 111 for rotatably arranging the winch 2. A fixed pulley 3 is arranged on the side surface of the base plate 111 connecting the ribs 112. Since the base plate 111 needs to withstand the first horizontal tension force applied by the steel cable 4 through the fixed pulley 3, the thickness of the base 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 11, the base plate 111 needs to be thickened. The wing plate 113 is connected to the base plate 111 through the rib plate 112, located on both sides of the two rib plates 112, and extends towards the base plate 111 away from the rib plate 112. The wing plate 113 is provided with a first connecting buckle 114 on the outer edge of the base plate 111. When a water retaining wall 1 is formed by several first piles 11, two adjacent first piles 11 can be connected by the first connecting buckle 114. After the two first piles 11 are connected by the first connecting buckle 114, the two first piles 11 have a water-blocking function.

[0047] In one embodiment, the first connecting buckle 114 may be a spiral bend of the outer edge of the wing plate 113 to form a vortex-shaped connecting buckle that can be interlocked with each other. Thus, after a first pile 11 is driven into the underwater foundation, the top and bottom of the two first piles 11 can be connected through the first connecting buckle 114, and then the second first pile 11 can be slid down until it is driven into the underwater foundation, so that the two first piles 11 can be connected through the first connecting buckle 114.

[0048] Furthermore, refer to Figure 5 , Figure 6 , Figure 9 as well as Figure 10 As shown, in some embodiments, the retaining wall 1 further 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 disposed 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 be connected by several second pile bodies 12. These second pile bodies 12 also adopt a steel structure and have a pile plate body 121, as detailed in the following reference. Figure 9 and Figure 10As shown, the pile plate body 121 can adopt a bent structure or an arc structure so that it can have better plasticity to adapt to the first pile body 11 that has been inserted when connecting the first pile body 11, thereby helping the first pile body 11 to resist water. On both sides of the outer edge of the pile plate body 121, there are second connecting buckles 122 that can be connected to the first connecting buckle 114. The second connecting buckle 122 adopts the same structure as the first connecting port, so it will not be described in detail.

[0050] It should be noted that because the structure of the second pile 12 is simpler than that of the first pile 11, the manufacturing cost of the second pile 12 is much lower than that of the first pile 11. When it is not necessary to install more winches 2 and fixed pulleys 3 on the retaining wall 1, the second pile 12 can be used to replace the first pile 11, thereby achieving the goal of saving the construction cost of the main body of the cofferdam.

[0051] Furthermore, refer to Figure 2 and Figure 7 As shown, in some embodiments, the winch 2 includes: a drum 21 rotatably disposed between two ribs 112; a backstop wheel 22 sleeved on the drum 21, and rotating synchronously with the drum 21, the backstop wheel 22 having a plurality of locking teeth arranged circumferentially; and a locking member 23 mounted on the rib 112 near the backstop wheel 22, the locking member 23 being inclinedly supported between two adjacent locking teeth so that the locking member 23 can prevent the drum 21 from rotating clockwise or counterclockwise on the rib 112.

[0052] Specifically, in the technical solution adopted in this application, since the anti-reverse wheel 22 is sleeved on the drum 21 and rotates synchronously with the drum 21, when the locking member 23 abuts against the anti-reverse wheel 22 in an inclined support manner, the anti-reverse wheel 22 can restrict the drum 21 from rotating in one direction without affecting its rotation in the other direction. Taking the clockwise and counterclockwise directions of the rib plate 112 as examples, when the locking member 23 is inclinedly supported on the locking teeth of the anti-reverse wheel 22, when the drum 21 rotates clockwise along the rib plate 112 and in accordance with the support direction of the locking member 23, the locking member 23 does not affect the normal rotation of the drum 21. Conversely, when the drum 21 rotates counterclockwise along the rib plate 112, the locking member 23 forms a supporting force between the rib plate 112 and the locking teeth to prevent the drum 21 from rotating counterclockwise along the rib plate 112. For example, rotating the drum 21 clockwise along the rib 112 is for taking in the steel cable 4, while rotating the drum 21 counterclockwise along the rib 112 is for leading out the steel cable 4. In this way, when adjusting the tension of the steel cable 4 applied to the first pile body 11 by rotating the drum 21, the tension of the steel cable 4 can be effectively prevented from failing due to the cooperation of the anti-reverse wheel 22 and the locking component 23.

[0053] Furthermore, refer to Figure 3 and Figure 8 As shown, in some embodiments, the fixed pulley 3 includes: two mounting lugs 31 fixed on one side surface of the base plate 111, the two mounting lugs 31 being arranged opposite to each other; and a pulley component 32 rotatably mounted on the two mounting lugs 31, the pulley component 32 having a groove 320 along the circumference, the groove 320 being used to fit the radial side of the steel cable 4.

[0054] Specifically, in the technical solution adopted in this application, in order to configure the fixed pulley 3 on the first pile body 11, two opposing mounting lugs 31 can be installed on the thickened base plate 111, and the pulley component 32 is rotatably configured on the two mounting lugs 31, so that the friction of the steel cable 4 when changing direction and adjusting tension can be reduced by the rotatable pulley component 32. In one embodiment, in order to avoid the steel cable 4 generating lateral friction on the pulley component 32, a groove 320 is provided on the radial side of the pulley component 32. When the steel cable 4 passes around the fixed pulley 3, the steel cable 4 can be embedded in the groove 320 of the pulley component 32, so that the steel cable 4 can slide in the groove 320 during the adjustment of tension, which can effectively avoid the misalignment of the steel cable 4 and the generation of unnecessary lateral friction on the pulley component 32, thereby reducing the frictional loss of the steel cable 4 and improving the service life of the steel cable 4.

[0055] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of those different embodiments or examples.

[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 indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0057] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing a particular logical function or process. Furthermore, the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functionality involved.

[0058] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can 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 processor-included system 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 this 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 memory and executed by a suitable instruction execution system. All or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware, the program being stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiments.

[0060] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium. This storage medium can be a read-only memory, a disk, or an optical disk, etc.

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

Claims

1. A construction method for a double-row steel sheet pile cofferdam, characterized in that, include: Hooks, winches with steel cables wound around them, and fixed pulleys for guiding the extension direction of the steel cables are installed at intervals along the height direction on the steel sheet piles. The steel cables led out by the winches are passed around the fixed pulleys, and the free end of the steel cables is connected to the hooks. The steel sheet piles are driven into the underwater foundation to form two rows of spaced water-retaining walls. The hook, the winch, and the fixed pulley are located on the opposite sides of the two rows of water-retaining walls, and the fixed pulley is located below the corresponding winch. The two steel cables fixed to the hooks on 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 tension force to the water-retaining wall through the fixed pulley, thereby enhancing the water-retaining wall's ability to resist lateral deformation. The intensity of the first horizontal tension force is adjusted in real time by synchronously monitoring the water-retaining wall underwater.

2. The construction method of the double-row steel sheet pile cofferdam according to claim 1, characterized in that, The method further includes, after sequentially untying the two steel cables fixed to the hooks on the two rows of retaining walls, connecting the free ends of the two steel cables to each other via a rope adapter, operating the winch to tension the steel cables so that the connected steel cables can apply a first horizontal tension force towards the retaining wall through the fixed pulley, thereby enhancing the retaining wall's ability to resist lateral deformation, and adjusting the intensity of the first horizontal tension force in real time through underwater synchronous monitoring of the retaining wall: Soil is filled into the space between the two rows of retaining walls. During the filling process, the winch is operated synchronously to dynamically adjust the tension of the steel cable on the steel sheet pile according to the filling height and the deformation of the steel sheet pile, until the soil reaches the target height. After the filled soil material has consolidated and settled in the underwater environment, the water enclosed by the retaining wall is pumped out to expose the underwater foundation as a dry construction surface.

3. The construction method of the double-row steel sheet pile cofferdam according to claim 2, characterized in that, The method further includes: sequentially untying the two steel cables fixed to the hooks on the two rows of retaining walls, connecting the free ends of the two steel cables together via a rope adapter, operating the winch to tension the steel cables, so that the connected steel cables can apply a first horizontal tension force towards the retaining wall through the fixed pulley, thereby enhancing the retaining wall's ability to resist lateral deformation; and through underwater synchronous monitoring of the retaining wall, real-time adjustment of the intensity of the first horizontal tension force and the method of filling the space between the two rows of retaining walls with soil, and during the soil filling process, dynamically adjusting the tension force applied to the steel sheet piles by the steel cables by synchronously operating the winch according to the soil filling height and the deformation of the steel sheet piles, until the soil reaches the target height. Tie rods are installed on the two rows of water-retaining walls. The tie rods apply a second horizontal tension force pointing towards the water-retaining wall. The tie rods are located above the fixed pulleys, so that the tie rods and the fixed pulleys form a constraint system that links the water-retaining walls vertically.

4. The construction method of the double-row steel sheet pile cofferdam according to claim 2, characterized in that, Before the method of pumping out the water enclosed by the retaining wall to expose the underwater foundation as a dry construction work surface after the soil to be filled has consolidated and settled in the underwater environment, the method further includes: A wall-mounted weir is constructed on the water-retaining wall, and the height of the wall-mounted weir is higher than the height of the water-retaining wall.

5. The construction method of the double-row steel sheet pile cofferdam according to claim 3, characterized in that, After the soil to be filled has consolidated and settled in the underwater environment, the water enclosed by the retaining wall is pumped out to expose the underwater foundation as a dry construction surface. Following this process, the retaining wall also needs to be dismantled, specifically including: The soil between the two rows of the retaining wall is removed in a layered manner, and the stability of the retaining wall is tested after the removal of each layer is completed. Control the water level difference between the inner and outer sides of the two rows of retaining walls; Remove the tie rods from the two rows of the retaining walls to release the second horizontal tension force exerted by the tie rods on the two rows of the retaining walls; Operate the winch to release the first horizontal tension force applied to the steel cable on the two rows of retaining walls; Remove the rope adapter from the steel cable and hang the two steel cables on the hooks corresponding to the steel sheet piles; Each of the sheet piles was removed from the underwater foundation, and the removed sheet piles were then recycled.

6. The construction method of the double-row steel sheet pile cofferdam according to claim 5, characterized in that, The method for removing soil between two rows of retaining walls in a layered manner, and for 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 is ≤2m.

7. The construction method of the 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 water level difference between the inside and outside of the two rows of retaining walls is controlled to be ≤0.5m.

8. The construction method of the 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 retaining walls to release the second horizontal tension force exerted by the tie rods on the two rows of retaining walls further includes: The preload applied to the two rows of retaining walls by the tie rod is released in a step-by-step manner, with an unloading interval of ≥2 hours between each step. The deformation of the retaining wall is monitored simultaneously. After the retaining wall becomes stable, the preload applied to the retaining wall by the tie rod is released step-by-step until the tie rod is removed from the retaining wall.

9. The construction method of the double-row steel sheet pile cofferdam according to claim 5, characterized in that, The method for removing each of the sheet piles from the underwater foundation and recycling the removed sheet piles includes: The steel sheet piles are removed from the retaining wall, and the target steel sheet piles are cyclically vibrated for 30 seconds before removal, with a vibration interval of two minutes. After successfully extracting the sheet pile from the underwater foundation, high-pressure water was used to remove any adhering substances from the surface of the sheet pile.

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

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