Waterfront double-row soil core steel sheet pile cofferdam in complex environment and construction method

Abstract

This invention discloses a double-row soil-core steel sheet pile cofferdam and its construction method in complex water-adjacent environments. The construction method is as follows: Step 1, construction preparation and surveying; Step 2, driving steel pipe piles; Step 3, installing guide frames on the driven steel pipe piles; Step 4, installing double-layer steel pipes; Step 5, guiding and positioning the steel sheet piles using the guide frames, double-layer steel pipes, and steel pipe piles, and then driving the steel sheet piles; Step 6, installing the waist beam and connecting components; Step 7, backfilling soil in the middle area of ​​the double-row steel sheet piles to form a soil core, and compacting it to ensure stability; Step 8, disassembling the guide system. This invention solves the technical problems of inaccurate positioning, low construction efficiency, and poor structural stability of double-row steel sheet piles in complex water-adjacent environments, and has the advantages of accurate positioning, firm connection, and reusability.

Description

Technical Field

[0001] This invention relates to the field of geotechnical engineering and hydraulic engineering construction technology, and in particular to a double-row soil core steel sheet pile cofferdam for use in complex environments (such as water flow, soft foundation, etc.) and its construction method. Background Technology

[0002] When constructing bridge piers, abutments, and water conservancy projects in complex water environments, gravity cofferdams with double-row steel sheet piles and soil cores can effectively block water. However, in deep water, fast-flowing water, or soft soil foundations, traditional guide frames lack rigidity and are fixed, making it difficult to effectively constrain and fine-tune the planar position and verticality of ultra-long steel sheet piles. Driving deviations can easily lead to uncontrolled spacing between the double rows of piles and the inability to smoothly install subsequent rigid connection systems such as waist beams and connecting beams, seriously affecting the overall sealing performance and structural profile accuracy of the cofferdam. Secondly, even if the steel sheet piles are driven into place, conventional cofferdam structures (such as simply setting internal supports) often fail to form a solid overall force-bearing system with the externally installed steel pipe piles. The lack of an efficient and reliable rigid force transmission mechanism between the steel sheet piles, waist beams, and steel pipe piles results in insufficient overall rigidity and stability of the cofferdam, posing safety hazards. In addition, the guide equipment in existing construction methods often suffers from poor adaptability, inconvenient disassembly and transportation, and inability to be repeatedly and accurately used in different construction sections, leading to poor process connections, long construction cycles, high costs, and significant risks in operation under harsh hydrological conditions. Therefore, there is an urgent need for a new type of cofferdam system and supporting construction method that integrates high-precision adjustable guidance technology with efficient overall connection structure. Summary of the Invention

[0003] The purpose of this invention is to provide a method for constructing a complex environment water-adjacent double-row soil core steel sheet pile cofferdam to solve the above-mentioned technical problems.

[0004] This invention discloses a construction method for a double-row soil-core steel sheet pile cofferdam in complex environments near water, comprising the following specific steps:

[0005] Step 1: Construction preparation and surveying / layout;

[0006] Step 2: Driving steel pipe piles:

[0007] Step 3: Install guide frames on the already driven steel pipe piles;

[0008] Step 4: Install double-layer steel pipes:

[0009] Step 5: Guide and position the sheet piles using a guide frame, double-layer steel pipes, and steel pipe piles, and then drive the sheet piles into place.

[0010] Step Six: Install the waist beam and connecting components:

[0011] Step 7: Backfill the middle area of ​​the double-row steel sheet piles with soil to form a soil core, and compact it to ensure stability;

[0012] Step 8: Disassemble the guide system.

[0013] As a preferred option, the specific method for step two is as follows: steel pipe piles are arranged at intervals on the outside of the cofferdam, and the steel pipe piles are driven vertically into the foundation using pile driving equipment to ensure that the spacing and position of the steel pipe piles meet the design requirements; and the verticality and stability of the steel pipe piles are checked to provide a foundation for the subsequent installation of the guide frame.

[0014] Preferably, in step three, the guide frame consists of a vertical beam, an upper horizontal beam, a lower horizontal beam, a triangular brace, and a base plate. The vertical beam is positioned between the upper and lower horizontal beams, and both the upper and lower horizontal beams have through holes through which the steel pipe piles pass. The upper and lower horizontal beams are fixed to the steel pipe piles. The triangular brace is positioned on both sides of the lower horizontal beam, and the base plate is positioned at the bottom of the triangular brace. A continuous node slot is provided on the base plate.

[0015] Preferably, in step four: the double-layer steel pipe includes an outer steel pipe and an inner steel pipe, with the outer steel pipe sleeved over the inner steel pipe. The outer and inner steel pipes are movably connected so that the inner steel pipe can rotate inside the pipe. The outer steel pipe has a disassembly slot that matches the node slot. Guide slots are spaced apart on both the inner and outer steel pipes. A positioning plate is installed in the guide slot of the inner steel pipe, and a guide rod is installed on the positioning plate. When installing the double-layer steel pipe, the double-layer steel pipe is inserted into the triangular support at the end and gradually slides forward, allowing the double-layer steel pipe to pass through multiple triangular supports in sequence. During the sliding process, the guide rod is at the disassembly slot, and as the guide rod slides forward, it passes through the node slots on each base plate in sequence.

[0016] As a preferred option, the specific method for step five is as follows:

[0017] S51. Insert the sheet pile into the gap between the double-layer steel pipes, and use the guide frame and the double-layer steel pipes to perform preliminary alignment of the sheet pile;

[0018] S52. Rotate one end of the inner steel pipe to make the inner steel pipe rotate as a whole, thereby causing the guide rod to swing towards the steel sheet pile side, so that one end of the guide rod presses against the steel sheet pile and makes fine adjustments to the state of the steel sheet pile; to ensure the verticality and planar position of the steel sheet pile are accurate;

[0019] S53. Use piling equipment to drive steel sheet piles into the foundation to form a double-row steel sheet pile structure; during the driving process, construct all steel sheet piles in sequence and ensure that the spacing between the double-row steel sheet piles and the width of the middle soil core area meet the design requirements.

[0020] As a preferred option, the specific method for step six is ​​as follows:

[0021] S61. Install a waist beam on the outer wall of the sheet pile: First, fix the base plate to the outer wall of the sheet pile, then install the base and positioning frame on the base plate, and install the steel pipe waler in the positioning frame.

[0022] S62. Install fixing rings on the steel pipe piles and fixing rings on the steel pipe walers. Then use connecting plates to connect the fixing rings and fixing rings to form a connection and fixation between the steel sheet piles and the waist beams and steel pipe piles.

[0023] As a preferred method, the specific method for step eight is as follows: After the steel sheet piles are driven, first rotate the inner steel pipe in the opposite direction to retract the guide rod into the guide groove and the disassembly groove; then, starting from the end, gradually slide the double-layer steel pipe out of the triangular support, and the guide rod passes through the node groove again during the sliding process to ensure smooth disassembly; finally, remove the guide frame from the steel pipe pile.

[0024] The complex environment water-adjacent double-row soil core steel sheet pile cofferdam was constructed using the construction method for complex environment water-adjacent double-row soil core steel sheet pile cofferdam.

[0025] The beneficial effects of this invention are as follows:

[0026] 1. High positioning accuracy and good construction quality. By setting up a multi-stage guiding system consisting of a guide frame, double-layer steel pipes, and guide rods, the "preliminary guidance" and "fine-tuning positioning" processes in the sheet pile driving are combined. The guide frame and double-layer steel pipes provide a stable initial positioning framework, while the extended guide rods, which can be finely adjusted by rotating the inner steel pipes, allow for precise fine-tuning of the position and verticality of each sheet pile. This effectively overcomes the influence of complex hydrological conditions on driving accuracy, ensuring that the spacing, planar position, and verticality of the double rows of sheet piles meet design requirements. This lays a solid foundation for the smooth installation of subsequent connecting components such as the waist beam and the overall sealing of the cofferdam.

[0027] 2. Significantly enhanced structural integrity and stability. Through the connecting plate design of "waist beam-steel pipe waler-fixing ring" and "steel pipe pile-fixing ring," the inner cofferdam system formed by double rows of steel sheet piles is firmly connected to the outer steel pipe pile support system into a unified whole. This rigid connection structure effectively transfers the earth pressure, water pressure, and other loads borne by the steel sheet piles to the more stable steel pipe piles, greatly improving the overall stiffness, overturning resistance, and sliding resistance of the cofferdam. It is particularly suitable for complex and harsh environments such as deep water and rapid currents, offering high safety assurance.

[0028] 3. High construction efficiency, strong adaptability and repeatability. The guiding system of this invention is ingeniously designed and easy to assemble and disassemble. The double-layer steel pipe adopts a movable insertion and sliding installation method, eliminating the need for frequent lifting with large hoisting equipment. The extension and retraction of the guide rod can be achieved through simple mechanical rotation, making operation simple and quick. The disassembly sequence is reversed, enabling rapid turnover. The entire system has a high degree of modularity and can be reused in different sections or other projects, significantly reducing the material waste and labor time caused by repeated welding and cutting of traditional fixed guide frames, greatly improving construction efficiency and reducing costs. Attached Figure Description

[0029] Figure 1 A schematic diagram of the construction of a double-row soil-core steel sheet pile cofferdam in a complex water environment.

[0030] Figure 2 for Figure 1 Another perspective on the construction diagram.

[0031] Figure 3 for Figure 1 Enlarged view of node A in the middle.

[0032] Figure 4 for Figure 2 Enlarged view of node B in the middle.

[0033] Figure 5 Schematic diagram of guide steel pipe.

[0034] Figure 6 for Figure 5 Enlarged view of node C in the middle.

[0035] In the diagram: 1. Sheet pile; 2. Soil core; 3. Waist beam; 4. Guide frame; 5. Steel pipe pile; 6. Steel pipe waler; 7. Base plate; 8. Base; 9. Positioning frame; 10. Fixing ring; 11. Fixing ring; 12. Connecting plate; 13. Upper crossbeam; 14. Vertical beam; 15. Lower crossbeam; 16. Triangular brace; 17. Base plate; 18. Node slot; 19. Outer steel pipe; 20. Inner steel pipe; 21. Assembly / disassembly slot; 22. Guide slot; 23. Positioning plate; 24. Guide rod. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0037] like Figures 1 to 6The present invention discloses a double-row soil-core steel sheet pile cofferdam for complex environments near water, comprising a cofferdam consisting of double rows of steel sheet piles 1 and a soil core 2 in between. The outer sides of the steel sheet piles 1 have spaced-apart steel pipe piles 5. The outer wall of the steel sheet piles 1 has a reinforcing girder 3, which includes a base plate 7 installed on the outer wall of the steel sheet piles 1. A base 8 is connected to the base plate 7, and a positioning frame 9 is provided on the base 8. A steel pipe waler 6 is installed inside the positioning frame 9. Simultaneously, fixing rings 10 and fixing rings 11 are respectively installed on the steel pipe piles 5 and the steel pipe waler 6, and the fixing rings 10 and fixing rings 11 are connected by a connecting plate 12. Based on this, the connection and fixation of the steel sheet piles 1 to the girder 3 and the steel pipe piles 5 are formed.

[0038] A guide frame 4 is installed on the steel pipe pile 5. The guide frame 4 is used for positioning and guidance when driving the steel sheet pile 1. The guide frame 4 includes a vertical beam 14, an upper horizontal beam 13, a lower horizontal beam 15, a triangular brace 16, and a base plate 17. The vertical beam 14 is located between the upper horizontal beam 13 and the lower horizontal beam 15. Both the upper horizontal beam 13 and the lower horizontal beam 15 are provided with through holes through which the steel pipe pile 5 can pass. The upper horizontal beam 13 and the lower horizontal beam are fixed on the steel pipe pile 5. The triangular brace 16 is located on both sides of the lower horizontal beam 15, and the base plate 17 is located at the bottom of the triangular brace 16. A continuous node slot 18 is provided on the base plate 17. A double-layer steel pipe is movably installed inside the triangular brace 16. The double-layer steel pipe includes an outer steel pipe 19 and an inner steel pipe 20. The outer steel pipe 19 is sleeved outside the inner steel pipe 20. The outer steel pipe 19 and the inner steel pipe 20 are movably connected so that the inner steel pipe 20 can rotate inside the steel pipe 19. The outer steel pipe 19 has a disassembly slot 21 inside, which matches the node slot 18. The guide frame 4 and the double-layer steel pipe are set on multiple steel pipe piles 5 that have been driven. The double-layer steel pipe is located on both sides of the steel sheet pile 1 to be constructed. Guide slots 22 are provided at intervals on both the inner steel pipe 20 and the outer steel pipe 19. A positioning plate 23 is installed in the guide slot 22 of the inner steel pipe 2, and a guide rod 24 is installed on the positioning plate 23. During construction, the guide frame 4 and the double-layer steel pipe are used for the initial guidance and positioning of the sheet pile 1, and the guide rod 24 is used for the fine-tuning guidance and positioning of the sheet pile 1. In the area to be constructed of the sheet pile 1, the double-layer steel pipe is movably installed in the triangular support 16, and the outer steel pipe 19 and the inner steel pipe 20 are movably connected. When installing the double-layer steel pipe, the double-layer steel pipe is inserted from the end of the triangular support 16 and gradually slid forward into multiple triangular supports 16. At this time, the guide rod 24 is exactly at the installation and disassembly slot 21. During sliding, the guide rod 24 can pass through the node slot 18 on the base plate 17, avoiding interference between the guide rod 24 and the base plate 17 and ensuring smooth installation of the double-layer steel pipe. After the double-layer steel pipe slides into place, the guide groove 22 on the inner steel pipe 20 corresponds to the guide groove 22 on the outer steel pipe 19. By rotating the inner steel pipe 20 at its end, the inner steel pipe 20 is rotated as a whole, which in turn causes the guide rod 24 to swing towards the steel sheet pile side, so that one end of the guide rod 24 presses against the steel sheet pile 1 and makes a fine adjustment to the state of the steel sheet pile. After the adjustment is completed, the end of the inner steel pipe 20 is temporarily fixed to maintain its current state. The construction sequence of disassembling the double-layer steel pipe is the reverse of the installation sequence, and the double-layer steel pipe can be flexibly placed in the area where the steel sheet pile 1 needs to be positioned.

[0039] This invention also provides a construction method for a cofferdam with two rows of soil cores and one steel sheet pile in a complex environment near water, comprising the following steps:

[0040] Step 1: Construction preparation and surveying; the specific methods are as follows:

[0041] S11. Based on the design drawings, conduct on-site measurements and layout in complex water-adjacent environments to determine the planar position and elevation of the cofferdam.

[0042] S12. Prepare the required materials: 1 double-row steel sheet piles, 5 steel pipe piles, 3 waist beam components (including base plate 7, base 8, positioning frame 9, steel pipe waler 6), 10 fixing rings, 11 fixing rings, 12 connecting plates, 4 guide frames (including vertical beams 14, horizontal beams 15, triangular braces 16, base plate 17), double-layer steel pipes (including outer steel pipes 19 and inner steel pipes 20), 23 positioning plates, 24 guide rods, etc.

[0043] Step 2: Driving steel pipe piles 5:

[0044] Steel pipe piles 5 are arranged at intervals on the outer side of the cofferdam. Piling equipment is used to drive the steel pipe piles 5 vertically into the foundation, ensuring that the spacing and position of the steel pipe piles 5 meet the design requirements. The verticality and stability of the steel pipe piles 5 are checked to provide a foundation for the subsequent installation of the guide frame 4.

[0045] Step 3: Install guide frame 4:

[0046] A guide frame 4 is installed on the already driven steel pipe piles 5. The guide frame 4 consists of a vertical beam 14, an upper horizontal beam 13, a lower horizontal beam 15, a triangular brace 16, and a base plate 17. The base plate 17 has a continuous node slot 18. The steel pipe piles 5 pass through the through holes on the upper horizontal beam 13 and the lower horizontal beam 15.

[0047] Step 4: Install double-layer steel pipes:

[0048] The double-layer steel pipe is movably installed inside the triangular support 16 of the guide frame 4. The outer steel pipe 19 and the inner steel pipe 20 of the double-layer steel pipe are movably connected. The outer steel pipe 19 is provided with a disassembly slot 21, which matches the node slot 18 on the base plate 17.

[0049] During installation, the double-layer steel pipe is inserted into the triangular support 16 at the end and gradually slid forward so that the double-layer steel pipe passes through multiple triangular supports 1 in sequence. During the sliding process, the guide rod 24 is at the installation and disassembly slot 21. As the guide rod 24 slides forward, it passes through the node slots 18 on each base plate 17 in sequence to ensure smooth installation of the double-layer steel pipe.

[0050] Step 5: Guide and position the sheet pile 1 using the guide frame 4, double-layer steel pipe, and steel pipe pile 5, and then drive the sheet pile 1 into place; the specific method is as follows:

[0051] S51. Use guide frame 4 and double-layer steel pipe for preliminary guidance and positioning of sheet pile 1: Insert sheet pile 1 into the gap between double-layer steel pipe, and rely on guide frame 4 and double-layer steel pipe to perform preliminary alignment of sheet pile 1.

[0052] S52. Fine-tuning the guide positioning: Rotate one end of the inner steel pipe 20 to make the inner steel pipe 20 rotate as a whole, thereby causing the guide rod 24 to swing towards the steel sheet pile 1, so that one end of the guide rod 24 presses against the steel sheet pile 1 and fine-tunes the state of the steel sheet pile 1; to ensure the verticality and planar position of the steel sheet pile 1 are accurate.

[0053] S53. Use piling equipment to drive steel sheet piles 1 into the foundation to form a double-row steel sheet pile 1 structure. During the driving process, construct all steel sheet piles 1 in sequence, and ensure that the spacing between the double-row steel sheet piles 1 and the width of the middle soil core 2 area meet the design requirements.

[0054] Step 6: Install waist beam 3 and connecting components:

[0055] S61. Install the waist beam 3 on the outer wall of the sheet pile 1: First, fix the base plate 7 on the outer wall of the sheet pile 1, then install the base 8 and the positioning frame 9 on the base plate 7, and install the steel pipe waler 6 inside the positioning frame 9.

[0056] S62. Install the fixing ring 10 on the steel pipe pile 5 and the fixing ring 11 on the steel pipe waler 6. Then use the connecting plate 12 to connect the fixing ring 10 and the fixing ring 11 to form a connection and fixation between the steel sheet pile 1, the waist beam 3, and the steel pipe pile 5.

[0057] Step 7: Formation of soil core 2 and completion of cofferdam:

[0058] Backfill the middle area of ​​the double-row sheet piles 1 with soil to form soil core 2, and compact it to ensure stability. Check the overall sealing and strength of the cofferdam, and reinforce it if necessary.

[0059] Step 8: Disassemble the guide system:

[0060] After the sheet pile 1 is driven, disassemble the guide frame 4 and the double-layer steel pipe. The disassembly sequence is the reverse of the installation sequence: first, rotate the inner steel pipe 20 in the opposite direction to retract the guide rod 24 into the guide groove 22 and the disassembly / removal slot 21; then, starting from the end, gradually slide the double-layer steel pipe out of the triangular support 16. During the sliding process, the guide rod 24 passes through the node slot 18 again to ensure smooth disassembly; finally, remove the guide frame 4 from the steel pipe pile 5. The double-layer steel pipe can be flexibly placed in other areas where the sheet pile 1 needs to be positioned and reused.

[0061] This invention is not limited to the preferred embodiments described above. Anyone can derive other products in various forms under the guidance of this invention. However, regardless of any changes in shape or structure, any technical solution that is the same as or similar to this application falls within the protection scope of this invention.

Claims

1. A construction method for a double-row soil-core steel sheet pile cofferdam in complex water environments, characterized in that, The specific steps include the following: Step 1: Construction preparation and surveying / layout; Step 2: Drive steel pipe piles (5); Step 3: Install guide frame (4) on the completed steel pipe pile (5); guide frame (4) consists of vertical beam (14), upper horizontal beam (13), lower horizontal beam (15), triangular brace (16) and base plate (17). Vertical beam (14) is set between upper horizontal beam (13) and lower horizontal beam (15). Both upper horizontal beam (13) and lower horizontal beam (15) are provided with through holes. Steel pipe pile (5) passes through the through holes on upper horizontal beam (13) and lower horizontal beam (15). Upper horizontal beam (13) and lower horizontal beam are fixed on steel pipe pile (5). Triangular brace (16) is set on both sides of lower horizontal beam (15). Base plate (17) is set at the bottom of triangular brace (16). Long node slot (18) is opened on base plate (17). Step 4: Install the double-layer steel pipe; the double-layer steel pipe includes an outer steel pipe (19) and an inner steel pipe (20). The outer steel pipe (19) is sleeved on the outside of the inner steel pipe (20). The outer steel pipe (19) and the inner steel pipe (20) are movably connected so that the inner steel pipe (20) can rotate inside the outer steel pipe (19). The outer steel pipe (19) has a disassembly slot (21), which matches the node slot (18). Guide slots (22) are provided at intervals on both the inner steel pipe (20) and the outer steel pipe (19). A positioning plate (23) is installed in the guide groove (22) of the inner steel pipe (20), and a guide rod (24) is installed on the positioning plate (23). When the double-layer steel pipe is installed, the double-layer steel pipe is inserted into the triangular support (16) at the end and gradually slides forward, so that the double-layer steel pipe passes through multiple triangular supports (16) in sequence. During the sliding process, the guide rod (24) is at the installation and disassembly slot (21), and the guide rod (24) passes through the node slots (18) on each base plate (17) in sequence during the forward sliding process. Step 5: Guide and position the sheet pile (1) using the guide frame (4), double-layer steel pipe, and steel pipe pile (5), and then drive the sheet pile (1); the specific method is as follows: S51. Insert the sheet pile (1) into the gap between the double-layer steel pipes, and use the guide frame (4) and the double-layer steel pipes to perform preliminary alignment of the sheet pile (1); S52. Rotate one end of the inner steel pipe (20) to make the inner steel pipe (20) rotate as a whole, thereby causing the guide rod (24) to swing toward the steel sheet pile (1), so that one end of the guide rod (24) presses against the steel sheet pile (1) and makes a fine adjustment to the state of the steel sheet pile (1); to ensure the verticality and planar position of the steel sheet pile (1) are accurate. S53. Use a pile driving device to drive steel sheet piles (1) into the foundation to form a double-row steel sheet pile (1) structure; during the driving process, construct all steel sheet piles (1) in sequence and ensure that the spacing of the double-row steel sheet piles (1) and the width of the middle soil core (2) area meet the design requirements. Step 6: Install the waist beam (3) and connecting components; Step 7: Backfill the soil in the middle area of ​​the double-row steel sheet piles (1) to form a soil core (2), and compact it to ensure stability; Step 8: Disassemble the guide system.

2. The construction method of a double-row soil-core steel sheet pile cofferdam in a complex environment near water, as described in claim 1, is characterized in that... The specific method of step two is as follows: steel pipe piles (5) are arranged at intervals on the outside of the cofferdam, and the steel pipe piles (5) are driven vertically into the foundation using pile driving equipment to ensure that the spacing and position of the steel pipe piles (5) meet the design requirements; and the verticality and stability of the steel pipe piles (5) are checked to provide a foundation for the subsequent installation of the guide frame (4).

3. The construction method of a double-row soil-core steel sheet pile cofferdam in a complex environment near water, as described in claim 1, is characterized in that... The specific method for step six is ​​as follows: S61. Install the waist beam (3) on the outer wall of the sheet pile (1): First, fix the base plate (7) on the outer wall of the sheet pile (1), then install the base (8) and the positioning frame (9) on the base plate (7), and install the steel pipe waler (6) in the positioning frame (9). S62. Install a fixing ring (10) on the steel pipe pile (5) and a fixing ring (11) on the steel pipe waler (6). Then use a connecting plate (12) to connect the fixing ring (10) and the fixing ring (11) to form a connection and fixation between the steel sheet pile (1) and the waist beam (3) and the steel pipe pile (5).

4. The construction method of a double-row soil-core steel sheet pile cofferdam in a complex environment near water, as described in claim 1, is characterized in that... The specific method for step eight is as follows: After the steel sheet pile (1) is driven, first rotate the inner steel pipe (20) in the opposite direction so that the guide rod (24) retracts into the guide groove (22) and the disassembly groove (21); then, starting from the end, gradually slide the double-layer steel pipe out of the triangular support (16), and the guide rod (24) passes through the node groove (18) again during the sliding process to ensure smooth disassembly; finally, remove the guide frame (4) from the steel pipe pile (5).

5. A double-row soil-core steel sheet pile cofferdam for complex environments near water, characterized in that... The cofferdam is constructed using the construction method of double-row soil-core steel sheet piles in complex environments near water, as described in any one of claims 1-4.

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