Prestressed assembly type cofferdam structure

Abstract

This invention proposes a prestressed prefabricated cofferdam structure, relating to the field of cofferdam construction technology in hydraulic engineering. Specifically, it discloses an inner layer of sheet piles, an outer layer of sheet piles, internal support beams, and a frame-shaped caisson. A transition channel is formed between the inner and outer layers of sheet piles, with the internal support beams evenly distributed within the transition channel to support the double-layer sheet piles. The caisson's sidewalls are circumferentially divided into inner and outer sheet pile slots, each containing a sealing gate. The double-layer sheet piles are installed in the corresponding slots. Multiple sets of anchor bolt structures are circumferentially inclined and extend through the sealing gates to the underwater strata for anchorage. The caisson's interior is equipped with a traction structure and a pushing structure. The pushing structure drives the sealing gates to vertical adaptive displacement, while the traction structure, relying on the anchor bolt structures as load-bearing fulcrums, applies prestress to the double-layer sheet piles and sheet pile slots, actively eliminating assembly gaps.

Description

Technical Field

[0001] This invention relates to the field of cofferdam construction technology in water conservancy projects, and more specifically, to a prestressed prefabricated cofferdam structure. Background Technology

[0002] In water-related engineering construction such as water conservancy bridges, waterway regulation, and underwater foundation pit excavation, cofferdams are the core temporary hydraulic structures for temporarily impounding and stopping water, and constructing dry working faces. Among them, double-row steel sheet pile cofferdams have become the most commonly used cofferdam type in inland rivers and small and medium-sized near-shore waters due to their advantages of light weight, convenient assembly and disassembly, and wide applicability. A conventional double-row steel sheet pile cofferdam consists of an inner layer of steel sheet piles, an outer layer of steel sheet piles, and internal bracing components between the piles. It relies on the double-layer sheet piles to form an isolation channel, and with the internal support, it resists the water and soil pressure from the outside, meeting the needs of foundation water-retaining construction.

[0003] Currently, the construction and structure of existing double-row steel sheet pile cofferdams still face several industry challenges: First, traditional cofferdams lack an integrated caisson base, requiring the individual driving of steel sheet piles and on-site welding of walers and support systems. This results in a large amount of underwater on-site work, a long construction period, and extremely high difficulty in underwater alignment and installation under deep water and rapid current conditions, leading to significant construction safety risks. Second, there are inherent assembly gaps between the steel sheet piles and the base. Conventionally, water sealing relies solely on the locking mechanism, leading to frequent joint leakage problems. Underwater gaps are difficult to seal manually, resulting in poor water sealing reliability and a high risk of seepage and excessive water accumulation on the inner side of the cofferdam, affecting dry-site construction of the foundation pit. Third, conventional cofferdams... The cofferdam relies solely on its own sheet pile weight and internal supports to resist water flow impact and lateral earth pressure, without external stratum anchoring structures. Under soft soil and silty underwater geological conditions, the cofferdam is prone to overall slippage and overturning deformation, resulting in insufficient overall structural stability. Fourth, traditional cofferdams lack active prestressing clamping structures, and the assembly gaps will continue to expand with water pressure and water flow vibration, gradually increasing leakage and resulting in high maintenance and leak sealing costs. Fifth, the existing steel sheet pile and caisson split structure cannot achieve adaptive clamping and matching between the tank and the sealing components. The sealing component fixing method is singular and cannot compensate for component processing tolerances and underwater assembly deviations, resulting in poor adaptability. Summary of the Invention

[0004] The purpose of this invention is to provide a prestressed prefabricated cofferdam structure that addresses the shortcomings of existing technologies and solves the problems mentioned in the background section.

[0005] The technical solution of this invention is implemented as follows: This invention provides a prestressed prefabricated cofferdam structure, including an inner layer of steel sheet piles and an outer layer of steel sheet piles disposed outside the inner layer of steel sheet piles, wherein a transition waterway is provided between the inner layer of steel sheet piles and the outer layer of steel sheet piles; The transition waterway is evenly provided with internal support steel beams that are fixed at both ends to the inner layer steel sheet piles and the outer layer steel sheet piles. The feature is that it also includes a frame-shaped caisson, wherein an inner layer steel sheet pile groove and an outer layer steel sheet pile groove are formed on the side wall of the caisson along its circumference, and the inner layer steel sheet pile groove is disposed in the outer layer steel sheet pile groove; Both the inner and outer sheet pile grooves are equipped with sealing gates, and the sealing gates extend outward from the inner or outer sheet pile grooves. The inner layer of sheet piles is installed in the inner layer sheet pile trench; the outer layer of sheet piles is installed in the outer layer sheet pile trench. Several anchor structures are installed obliquely along the circumference of the side wall of the caisson, and the anchor structures extend outward after penetrating the side wall of the sealing gate; a traction structure is installed inside the caisson for pulling the inner and outer steel sheet pile grooves toward the sealing gate; the traction structure is connected to the anchoring end of the anchor structure.

[0006] In some technical solutions of the present invention, the caisson is provided with a pushing structure, the telescopic end of the pushing structure is connected to the sealing gate, and the pushing structure is used to push the sealing gate to move in the vertical direction.

[0007] In some technical solutions of the present invention, the pushing structure includes a plurality of second hydraulic push rods installed in the inner layer steel sheet pile groove or the outer layer steel sheet pile groove, and the telescopic end of the hydraulic push rod is hinged to its corresponding sealing gate.

[0008] In some technical solutions of the present invention, the anchor structure includes a guide pipe installed on the side wall of the caisson, an installation channel is provided on the side wall of the sealing gate in the vertical direction, the guide pipe extends outward after passing through the installation channel, one end of the guide pipe is installed inside the caisson, an anchor body is installed inside the guide pipe, a second hydraulic push rod is provided inside the caisson, and the telescopic end of the second hydraulic push rod is connected to the anchor body.

[0009] In some technical solutions of the present invention, the traction structure includes a guide wheel and a pressure beam installed in a guide tube. A prestressed rope is wound around the guide wheel. An installation seat is rotatably provided on the outer side wall of the anchor body. One end of the prestressed rope is connected to the installation seat. The pressure beam overlaps between the inner layer steel sheet pile and the outer layer steel sheet pile, and parts of the inner layer steel sheet pile and the outer layer steel sheet pile are respectively embedded in the pressure beam. The other end of the prestressed rope passes around the guide wheel, passes through the sealing gate and the inner layer steel sheet pile in sequence, and is detachably connected to the pressure beam by bolts or hooks.

[0010] In some technical solutions of the present invention, a pressure plate is hinged to the side wall of the sealing gate, a top rod is provided in the sealing gate along the vertical direction, the top rod is hinged to the pressure plate, and the free end of the top rod abuts against the inner layer steel sheet pile or the outer layer steel sheet pile.

[0011] In some technical solutions of the present invention, a sealing strip is provided in the mounting groove, and a sealing channel matching the inner layer steel sheet pile or the outer layer steel sheet pile is opened on the sealing strip. The inner layer steel sheet pile or the outer layer steel sheet pile extends outward after passing through the sealing channel.

[0012] In some technical solutions of the present invention, the sealing strip is embedded in the airbag structure connected end to end.

[0013] In some technical solutions of the present invention, a sealing door is installed in the transition waterway, one side of the sealing door abuts against the pressure beam, and the other side of the sealing door is embedded in the caisson.

[0014] In some technical solutions of the present invention, the inner steel sheet pile is provided with a frame-shaped support structure, and several support points of the support structure are detachably connected to the inner wall of the inner steel sheet pile.

[0015] Compared with the prior art, the present invention has at least the following advantages or beneficial effects: relying on the integrated prefabricated foundation of the caisson, it avoids the traditional on-site concrete pouring process of the cofferdam, uses the self-weight of the caisson to achieve underwater autonomous positioning, and the layered double-layer steel sheet pile trenches achieve precise alignment and assembly of the double-layer water-retaining steel sheet piles. Together with the internal support steel beams, it forms a double-layer cavity isolation channel, and relies on the double-layer steel sheet piles to share the pressure of the outer water flow, thereby improving the overall bearing capacity of the cofferdam foundation.

[0016] The sealing gate is driven vertically by a multi-point articulated hydraulic push rod, adapting to the installation conditions of sheet piles of different lengths and embedment depths. Combined with the top rod-pressure plate articulated transmission structure, the vertical linear motion is converted into rotational pressing motion, achieving local rigid pressing between the sealing gate and the outer wall of the sheet pile. At the same time, the flexible sealing strip is made to adaptively fill the component processing tolerances and assembly gaps by utilizing the airbag inflation deformation principle, achieving a double sealing and water stopping of rigid pressing + flexible filling, preventing water from seeping in from the assembly gaps.

[0017] Then, by using guide pipes to constrain the angle of the anchor bolts' extension, the force direction of all anchor bolts is ensured to be uniform, firmly anchoring the entire cofferdam to the underwater strata, offsetting the lateral impact force of the water flow and the lateral pressure of the soil and water, and eliminating the risk of cofferdam slippage and overturning; at the same time, using the anchor bolts as the prestressed tension fixing fulcrum, the tension direction is reversed by relying on guide wheels, converting the axial tension of the anchor bolts into lateral compressive traction force, and simultaneously pulling the double-layer steel sheet pile grooves to compress the sealing gate through the pressure beam, actively eliminating assembly gaps, applying prestress to the entire cofferdam, and improving the overall rigidity of the structure. Attached Figure Description

[0018] Figure 1 This is a three-dimensional structural diagram of the prestressed prefabricated cofferdam structure in this invention.

[0019] Figure 2This is a top view schematic diagram of the prestressed prefabricated cofferdam structure in this invention.

[0020] Figure 3 This is a side sectional view of the caisson structure in this invention.

[0021] Figure 4 This is a top view schematic diagram of the installation structure of the traction structure in this invention.

[0022] Figure 5 This is a schematic diagram of the installation structure of the pressure plate in this invention.

[0023] Figure 6 This is a top view of the pressure beam structure in this invention.

[0024] Reference numerals: 1-Inner sheet pile; 2-Outer sheet pile; 3-Transition waterway; 4-Inner support beam; 5-Ceiling; 501-Inner sheet pile trench; 502-Outer sheet pile trench; 6-Sealing gate; 601-Installation channel; 602-Pressure plate; 603-Top rod; 7-Anchor structure; 701-Guide pipe; 702-Anchor body; 703-Anchoring hydraulic push rod; 8-Traction structure; 801-Guide wheel; 802-Prestressed rope; 803-Pressure beam; 804-Rotating mounting seat; 9-Pushing structure; 901-Second hydraulic push rod; 10-Sealing strip; 101-Sealing channel; 102-Airbag structure; 11-Sealing door; 12-Support structure. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0026] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0027] Example This invention provides a prestressed prefabricated cofferdam structure, such as... Figures 1-6As shown, the specific setup is as follows: the inner layer of steel sheet piles 1 and the outer layer of steel sheet piles 2 form the main body of the cofferdam, and a transition waterway 3 is formed between the two layers of steel sheet piles. Multiple sets of inner support steel beams 4 are evenly arranged along the circumference of the main body of the cofferdam in the transition waterway 3. The two ends of the inner support steel beams 4 are fixedly connected to the inner layer of steel sheet piles 1 and the outer layer of steel sheet piles 2 by bolts. The rigid support of the steel beams is used to share the lateral water pressure of the water body and maintain the shape of the double-layer steel sheet pile foundation.

[0028] Preferably, the inner sheet pile 1 and the outer sheet pile 2 are bent into a corrugated plate structure by a bending device, and both the inner sheet pile 1 and the outer sheet pile 2 are spliced ​​together by multiple plate structures, with any two adjacent plate structures interlocking with each other.

[0029] Caisson 5 serves as the underwater assembly foundation and load-bearing base for the entire cofferdam. Its overall shape is frame-like, and its inner wall space, together with the double-layer sheet piles, forms a construction enclosure area. The sidewalls of caisson 5 are circumferentially divided into inner sheet pile slots 501 and outer sheet pile slots 502, both of which are annular. The inner sheet pile slot 501 is embedded within the outer sheet pile slot 502, used for the layered alignment and installation of the inner sheet piles 1 and outer sheet piles 2. The inner sheet piles 1 are correspondingly embedded in the inner sheet pile slot 501, and the outer sheet piles 2 are correspondingly embedded in the outer sheet pile slot 502, completing the initial assembly and connection between the cofferdam's water-retaining body and caisson 5. Both sets of sheet pile trenches are equipped with sealing gates 6. The sealing gates 6 are formed by welding double-layer steel plates to form a frame structure. The partial structure of the sealing gates 6 extends outward and protrudes from the outside of the sheet pile trench. The sealing gates 6 fit against the inner wall of the sheet pile trench. After the initial assembly and docking of the cofferdam water-retaining body and the caisson 5, when the caisson 5 is lowered into the water, the caisson 5 and the sealing gates 6 use their own weight to embed the sealing gates 6 partially into the river channel, preventing river water from leaking from the bottom of the caisson 5 into the enclosure area formed by the cofferdam water-retaining body and the caisson 5.

[0030] Construction workers installed multiple sets of anchor bolt structures 7 along the circumferential angle on the side wall of the caisson 5. The anchor bolt structure 7 extends outward to the underwater stratum after penetrating the side wall of the sealing gate 6, thus anchoring and fixing the entire cofferdam to the underwater rock and soil. The caisson 5 integrates a traction structure 8, which forms a transmission cooperation with the anchor bolt structure 7. It can pull the inner steel sheet pile 1 in the inner steel sheet pile groove 501 and the outer steel sheet pile 2 in the outer steel sheet pile groove 502 to move towards the sealing gate 6, and apply a downward thrust to the sealing gate 6 and act on the caisson 5. The anchor bolt structure 7 is used to prevent the caisson 5 from floating. The downward pressure applied by the anchor bolt structure 7 and the traction structure 8 to the main body of the cofferdam can prestress and lock the assembly gap between the main body of the cofferdam and the caisson 5, preventing river water from entering the enclosure area.

[0031] In order to adaptively adjust the vertical position of the sealing gate 6 to adapt to different burial depths, a pushing structure 9 is installed inside the caisson 5. The telescopic end of the pushing structure 9 is rigidly connected to the sealing gate 6, which can drive the sealing gate 6 to move up and down in the vertical direction. The pushing structure 9 specifically adopts multiple sets of second hydraulic push rods 901. The hydraulic push rods are respectively installed inside the inner steel sheet pile groove 501 or the outer steel sheet pile groove 502. The telescopic end of the push rod is hinged to the corresponding sealing gate 6 to avoid rigid jacking causing deformation and jamming of the components.

[0032] In this embodiment, the anchor structure 7 is equipped with a guide and limiting structure. A guide pipe 701 is fixedly installed on the side wall of the caisson 5. An installation channel 601 matching the guide pipe 701 is opened in the vertical direction on the side wall of the sealing gate 6. The guide pipe 701 extends outward through the installation channel 601, and one end of the guide pipe 701 is fixed inside the caisson 5. An anchor body 702 is installed inside the pipe. A hydraulic push rod is installed inside the caisson 5. The telescopic end of the push rod is connected to the anchor body 702, which can control the directional extension and retraction of the anchor body 702 along the guide pipe 701 to complete the anchoring and loosening actions. Preferably, the anchor structure 7 is inclined downstream at 15°.

[0033] In this embodiment, the traction structure 8 adopts a pulley reversing traction structure. A guide wheel 801 and a pressure beam 803 are installed inside the guide tube 701. A prestressed tension rope 802 is wound around the guide wheel 801. The outer wall of the anchor body 702 is rotated to assemble the mounting seat. One end of the prestressed tension rope 802 is hinged to the mounting seat and fixed. The other end passes around the guide wheel 801 and then passes through the cable channel set on the sealing gate 6 and the inner steel sheet pile 1 in sequence, and finally is fixedly connected to the pressure beam 803. The pressure beam 803 overlaps between the inner and outer steel sheet piles 2. The two layers of steel sheet piles are partially embedded in the pressure beam 803. The overall prestressing is achieved by relying on the tension rope to transmit force.

[0034] To further enhance the local sealing effect, a pressure plate 602 is hinged to the side wall of the sealing gate 6, and a top rod 603 is vertically inserted inside the sealing gate 6. The top rod 603 is hinged to the pressure plate 602, and the free end of the lower end of the top rod 603 can abut against the outer wall of the steel sheet pile, converting the vertical displacement of the top rod 603 into the rotational clamping force of the pressure plate 602, filling the tiny gaps between the sealing gate 6 and the steel sheet pile. A sealing strip 10 is installed inside the steel sheet pile groove. The sealing strip 10 has a sealing channel 101 that matches the outer diameter of the steel sheet pile. The steel sheet pile is arranged through the sealing channel 101. An airbag structure 102 with connected ends is embedded inside the sealing strip 10, which achieves self-adaptive sealing of the gaps through inflation.

[0035] A sealing door 11 is installed inside the transition waterway 3. One end face of the sealing door 11 abuts against the pressure beam 803 for limitation, and the other side is embedded and fixed inside the caisson 5, which can realize the control of the water flow in the transition waterway 3. A detachable frame support structure 12 is installed inside the inner steel sheet pile 1. The support structure 12 is detachably connected to the inner wall of the inner steel sheet pile 1 at multiple points, providing internal rigid support for the inner steel sheet pile 1 and resisting the internal water and soil pressure.

[0036] The overall construction process of this prestressed prefabricated cofferdam is divided into six steps: underwater positioning of the caisson 5, assembly of double-layer steel sheet piles, installation and commissioning of the sealing structure, anchoring and prestressing locking of anchor bolts, water control and retention operations of the cofferdam, and dismantling and recycling after construction. The specific process is as follows: Caisson 5 is precisely positioned underwater: The caisson 5 is prefabricated on land in advance, and the frame caisson 5 is transported to the designated underwater construction location by floating equipment. The caisson 5 sinks to the bottom surface by its own weight, and the positioning and leveling of the caisson 5 are completed. It serves as the basic carrier for the subsequent assembly of all components, ensuring that the installation benchmarks of the steel sheet piles and sealing gate 6 are consistent.

[0037] Double-layer sheet pile alignment and assembly: The inner sheet pile 1 and the outer sheet pile 2 are hoisted and lowered in sequence and embedded into the inner sheet pile groove 501 and the outer sheet pile groove 502 on the circumferential side wall of the caisson 5, respectively. The sheet piles pass through the sealing channel 101 of the sealing strip 10 in the groove, completing the initial positioning of the pile body; then, the inner support steel beam 4 is evenly distributed between the two layers of sheet piles, and the two ends of the steel beam are welded and fixed to the inner and outer sheet piles respectively to form a stable double-layer isolation transition waterway 3.

[0038] Vertical adjustment and pre-sealing of the sealing gate 6: The second hydraulic push rod 901 inside the steel sheet pile trench is activated. The telescopic end of the hydraulic push rod drives the hinged sealing gate 6 to rise and fall vertically. According to the actual depth of the steel sheet pile, the vertical height of the sealing gate 6 is precisely adjusted so that the outer extension of the sealing gate 6 is completely in contact with the outer wall of the steel sheet pile. Then, the internal push rod 603 of the sealing gate 6 is pushed vertically, which drives the side wall pressure plate 602 to rotate and press against the outer wall of the steel sheet pile, completing the initial sealing of the local gaps. The air bladder inside the sealing strip 10 is inflated. The expansion of the air bladder causes the sealing strip 10 to adaptively fill the irregular assembly gap between the pile body and the pile trench, achieving the first sealing and water stop.

[0039] Anchor bolt structure 7 installation and ground anchoring: The guide pipe 701 of the side wall of the caisson 5 passes through the installation channel 601 of the sealing gate 6 to complete the directional installation. The matching hydraulic pusher is activated to push the anchor bolt body 702 outward along the guide pipe 701 and penetrate into the underwater rock and soil to complete the anchoring and fixation of the entire cofferdam to the underwater stratum, limiting the overall slippage and overturning displacement of the cofferdam. After the anchor bolt body 702 is in place, it remains in the extended state to provide a force support point for subsequent prestressing tensioning.

[0040] The traction structure 8 is prestressed and the whole structure is locked and sealed: relying on the rotating mounting seat 804 on the anchor body 702, the prestressed rope 802 is pulled. The rope is driven by the guide wheel 801 to pull the pressure beam 803 laterally. The inner steel sheet pile groove 501 and the outer steel sheet pile groove 502 are pulled together and pressed towards the sealing gate 6. The assembly gap between the steel sheet pile, the pile groove and the sealing gate 6 is eliminated to form an overall prestressed locking structure. At the same time, the pressure beam 803 presses against the sealing door 11 in the transition waterway 3 to achieve complete water-proof sealing of the transition waterway 3. The cofferdam forms a closed water-blocking cavity and the foundation pit drainage and water construction can be carried out.

[0041] After construction, component dismantling and recycling: After the water area construction task is completed, firstly, release the gas inside the airbag of sealing strip 10, and the airbag will contract to release the tight seal; retract the anchor rod body 702 in the reverse direction to release the underwater anchoring force of the cofferdam; control the traction structure 8 to release the prestressed rope 802 in the reverse direction to release the clamping force between the steel sheet pile groove and the sealing gate 6; retract the hydraulic push rod to drive the sealing gate 6 to move vertically downward to reset, and release the limit of the sealing gate 6; finally, dismantle the inner support steel beam 4 and the inner support structure 12 in sequence, pull out the inner steel sheet pile 1 and the outer steel sheet pile 2 in steps, lift and retrieve the caisson 5, and all core components can be transferred to the next construction site for reuse.

[0042] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A prestressed prefabricated cofferdam structure, comprising an inner layer of steel sheet piles and an outer layer of steel sheet piles disposed outside the inner layer of steel sheet piles, wherein a transition waterway is provided between the inner layer of steel sheet piles and the outer layer of steel sheet piles; The transition waterway is evenly provided with internal support steel beams that are fixed at both ends to the inner layer steel sheet piles and the outer layer steel sheet piles. Its features are, It also includes a frame-shaped caisson, on the side wall of which an inner steel sheet pile groove and an outer steel sheet pile groove are provided along its circumference, and the inner steel sheet pile groove is located inside the outer steel sheet pile groove. Both the inner and outer sheet pile grooves are equipped with sealing gates, and the sealing gates extend outward from the inner or outer sheet pile grooves. The inner layer of sheet piles is installed in the inner layer sheet pile trench; the outer layer of sheet piles is installed in the outer layer sheet pile trench. Several anchor structures are installed obliquely along the circumference of the side wall of the caisson, and the anchor structures extend outward after penetrating the side wall of the sealing gate; a traction structure is installed inside the caisson for pulling the inner and outer steel sheet pile grooves toward the sealing gate; the traction structure is connected to the anchoring end of the anchor structure.

2. The prestressed prefabricated cofferdam structure according to claim 1, characterized in that, The caisson is equipped with a pushing structure, the telescopic end of which is connected to the sealing gate. The pushing structure is used to push the sealing gate to move in the vertical direction.

3. A prestressed prefabricated cofferdam structure according to claim 2, characterized in that, The pushing structure includes several second hydraulic push rods installed in the inner or outer steel sheet pile groove, with the telescopic end of the hydraulic push rod hinged to its corresponding sealing gate.

4. A prestressed prefabricated cofferdam structure according to claim 1, characterized in that, The anchor structure includes a guide pipe installed on the side wall of the caisson. An installation channel is provided on the side wall of the sealing gate in the vertical direction. The guide pipe extends outward after passing through the installation channel. One end of the guide pipe is installed inside the caisson. An anchor body is installed inside the guide pipe. A second hydraulic push rod is provided inside the caisson. The telescopic end of the second hydraulic push rod is connected to the anchor body.

5. A prestressed prefabricated cofferdam structure according to claim 4, characterized in that, The traction structure includes a guide wheel and a pressure beam installed in a guide tube. A prestressed rope is wound around the guide wheel. A mounting seat is rotatably provided on the outer wall of the anchor body. One end of the prestressed rope is connected to the mounting seat. The pressure beam overlaps between the inner layer steel sheet piles and the outer layer steel sheet piles, and parts of the inner layer steel sheet piles and the outer layer steel sheet piles are respectively embedded in the pressure beam. The other end of the prestressed rope passes around the guide wheel, passes through the sealing gate and the inner layer steel sheet pile in sequence, and then connects to the pressure beam.

6. A prestressed prefabricated cofferdam structure according to claim 5, characterized in that, A pressure plate is hinged to the side wall of the sealing gate, and a top rod is inserted vertically inside the sealing gate. The top rod is hinged to the pressure plate, and the free end of the top rod abuts against the inner or outer steel sheet pile.

7. A prestressed prefabricated cofferdam structure according to any one of claims 1-6, characterized in that, The mounting groove is equipped with a sealing strip, and the sealing strip has a sealing channel that matches the inner layer steel sheet pile or the outer layer steel sheet pile. The inner layer steel sheet pile or the outer layer steel sheet pile extends outward after passing through the sealing channel.

8. A prestressed prefabricated cofferdam structure according to claim 7, characterized in that, The sealing strip is embedded in the airbag structure that is connected end to end.

9. A prestressed prefabricated cofferdam structure according to claim 5, characterized in that, A sealing door is installed inside the transition waterway. One side of the sealing door abuts against the pressure beam, and the other side of the sealing door is embedded in the caisson.

10. A prestressed prefabricated cofferdam structure according to claim 1, characterized in that, The inner sheet pile is provided with a frame-shaped support structure, and several support points of the support structure are detachably connected to the inner wall of the inner sheet pile.

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