Tidal Influence on Steel Sheet Pile Island Cofferdam and Construction Method

Abstract

The present invention relates to a steel sheet pile island cofferdam affected by tides and a construction method, which includes the steps of: constructing high-pressure jet grouting piles; driving steel pipe piles, erecting a steel temporary bridge and installing a guiding frame; connecting a steel sheet pile driving module; installing adjustable braces under the steel beam and connecting a cofferdam filling module; building a sand-filled cofferdam in a silty soil layer; installing wave-proof blocks on the water-facing side of the sand-filled cofferdam; and backfilling with soil until the design elevation. The beneficial effects of the present invention are as follows: The structure of arranging two rows of Larssen steel sheet piles on the water-facing side of the cofferdam main body, and arranging adjustable braces and high-pressure jet grouting piles between the two rows of Larssen steel sheet piles greatly improves the stability and safety of the water-facing side of the cofferdam; by using adjustable braces, the height of the vertical rods is adjusted to control the position of the horizontal support, and the deformation and stress conditions of the Larssen steel sheet piles at the position where they are located can be measured in real time through the axial force sensors and displacement sensors on the horizontal support, effectively controlling the deformation and stress of the Larssen steel sheet piles.

Description

Technical Field

[0001] The invention belongs to the technical field of steel sheet pile island building cofferdams, and particularly relates to a steel sheet pile island building cofferdam affected by tides and a construction method thereof. Background Art

[0002] With the development of the economic society, the demand for domestic and production water of urban and rural residents is increasing continuously, and a large number of important water diversion projects have emerged. The construction of such projects inevitably requires the construction of working wells and receiving wells involving complex water areas. Among them, the island building cofferdam not only provides a safe and convenient construction environment for construction workers, but also ensures the smooth progress of the working well and receiving well projects.

[0003] Steel sheet piles have the advantages of good waterproof performance, simple construction, recyclability and repeated utilization, etc., and can be used for the construction of island building cofferdams. However, currently, there are relatively few projects applying steel sheet piles to the construction of island building cofferdams. Through analysis, it is found that the following problems exist specifically: At present, the state has not issued relevant specifications for steel sheet pile construction; applying steel sheet piles to the construction of island building cofferdams, especially in projects with complex tidal effects, is more difficult. The construction of a steel sheet pile island building cofferdam first needs to determine the island building area. If construction operations are carried out in a nature reserve, the access roads for construction materials and machinery need to be considered, and at the same time, sufficient working space needs to be ensured to minimize the impact of construction on the surrounding environment; in fact, the filling efficiency inside and outside the island building cofferdam is significantly affected by many factors such as complex tides, water pressure, and site environment.

[0004] Therefore, in order to improve the construction efficiency and engineering safety of island building cofferdams in tidal influence areas, it is urgent to develop an economic, environmentally friendly and efficient steel sheet pile island building cofferdam and construction method that can make full use of on-site resources. Summary of the Invention

[0005] The purpose of the invention is to overcome the deficiencies in the prior art and provide a steel sheet pile island building cofferdam affected by tides and a construction method thereof.

[0006] This steel sheet pile island building cofferdam affected by tides includes a cofferdam main body, a water-facing side anti-scouring system and an Internet of Things control system; the cofferdam main body includes Larsen steel sheet piles, steel beams, adjustable struts and water and soil pressure sensors;

[0007] There are two rows of Larsen steel sheet piles on the water-facing side of the cofferdam main body, and each row of Larsen steel sheet piles is mutually engaged through tongue-and-groove joints; high-pressure water pipes are arranged on the inner walls of the tongue-and-groove joints of the Larsen steel sheet piles; the water and soil pressure sensors are fixed on the Larsen steel sheet piles; the Larsen steel sheet piles are connected to the upper steel beams; the top ends of the adjustable struts are connected to the steel beams, and the adjustable struts top support the two rows of Larsen steel sheet piles; backfill soil is filled in the area enclosed by the Larsen steel sheet piles, and settlement monitoring sensors are arranged on the top surface of the backfill soil;

[0008] It also includes steel pipe piles, and guide frames for driving Larsen steel sheet piles are arranged on the steel pipe piles;

[0009] The water-facing side anti-erosion system includes a sand-filled cofferdam and wave-proof blocks; the sand-filled cofferdam is arranged on the water-facing side of the Larssen sheet piles; the wave-proof blocks are arranged on the water-facing side of the sand-filled cofferdam.

[0010] The Internet of Things control system includes a sheet pile driving module and a cofferdam filling module; the sheet pile driving module is connected to the guide frame and the high-pressure water pump; the cofferdam filling module is connected to the adjustable support, the water and soil pressure sensor, and the settlement monitoring sensor.

[0011] Preferably: The joints of the Larssen sheet piles are painted with a mixture of asphalt and butter ointment; the Larssen sheet piles enclose the contour of the cofferdam main body; the upper port of the high-pressure water pipe is connected to the high-pressure water pump; the Larssen sheet piles are perpendicular to the horizontal elevation; the Larssen sheet piles are connected by steel wales; the steel wales are welded to the upper part of the Larssen sheet piles.

[0012] The Larssen sheet piles are connected to the upper steel beam through a hoop structure; the adjustable support is installed between two rows of Larssen sheet piles, and the adjustable support includes a vertical rod and a horizontal support; displacement and force sensors are provided on both the vertical rod and the horizontal support, and hydraulic components for adjusting the length are provided on both the vertical rod and the horizontal support; the horizontal support braces against two rows of Larssen sheet piles.

[0013] It also includes high-pressure jet grouting piles, which are arranged between two rows of Larssen sheet piles on the water-facing side of the cofferdam main body and close to one row of Larssen sheet piles on the offshore side of the cofferdam; the top surface of the high-pressure jet grouting piles is lower than the original ground at the construction site.

[0014] Preferably: The water and soil pressure sensor is welded to the Larssen sheet pile through a protective sleeve, and the bottom of the water and soil pressure sensor is flush with the current river bottom elevation, the bottom of the high-pressure jet grouting pile, and the bottom of the Larssen sheet pile respectively.

[0015] Preferably: The top surface of the backfill soil is flush with the top of the steel beam; a steel temporary bridge is erected on the upper part of the steel pipe pile, and the guide frame is erected on the steel temporary bridge; a Larssen sheet pile is also vertically driven under the guide frame; the steel pipe pile is parallel to the Larssen sheet pile; the guide frame is provided with a vertical sensor, the steel pipe pile is rigidly connected to the steel temporary bridge, and the steel pipe pile is the lower pier structure of the steel temporary bridge; the deck of the steel temporary bridge is flush with the upper part of the steel beam.

[0016] Preferably: The sand-filled cofferdam includes precast high-rise tongue-and-groove plates, and four precast high-rise tongue-and-groove plates are assembled into a rectangle, and the rectangle is filled with fine sand; the sand-filled cofferdam is arranged on the water-facing side of the cofferdam main body and inserted into the silt layer; the precast high-rise tongue-and-groove plates are connected in a wedge shape; several steel hoops are sleeved on the outer side wall of the precast high-rise tongue-and-groove plates.

[0017] The wave-dissipating block is made of concrete material. The top of the wave-dissipating block is lower than the top of the precast slab with a raised socket. The wave-dissipating block is in a slope shape.

[0018] This construction method of a steel sheet pile island-building cofferdam affected by tides includes the following steps:

[0019] S1. Clear the site and measure and set points; construct high-pressure jet grouting piles; drive steel pipe piles, build a steel temporary bridge and erect a guide frame; connect the steel sheet pile driving module.

[0020] S2. Assist in driving the Larsen steel sheet piles equipped with high-pressure water pipes and soil pressure sensors through the steel sheet pile driving module; weld steel girders; use a hoop structure to connect the steel beam and the Larsen steel sheet piles; install adjustable braces under the steel beam and connect the cofferdam filling module.

[0021] S3. Build a sand-filled cofferdam in the silty soil layer; synchronously fill the backfill soil in the area enclosed by the Larsen steel sheet piles and the fine sand in the sand-filled cofferdam, and adjust the adjustable braces and the backfill speed of the backfill soil in real time according to the cofferdam filling module.

[0022] S4. When the height of the backfill soil between the two rows of Larsen steel sheet piles on the water-facing side of the cofferdam main body reaches the design elevation of the fine sand, pause the backfill, and fill the backfill soil in other areas of the cofferdam to the design elevation; install wave-dissipating blocks on the water-facing side of the sand-filled cofferdam.

[0023] S5. Remove the Internet of Things system, guide frame, adjustable braces, hoop structure, steel beam, steel girders and Larsen steel sheet piles in sequence, and backfill the backfill soil until the design elevation.

[0024] S6. After the island-building cofferdam and related projects are all constructed, remove the steel pipe piles and the steel temporary bridge.

[0025] Preferably, in step S2, the steel sheet pile driving module controls the verticality of the Larsen steel sheet piles during driving through the feedback information of the vertical sensors on the guide frame; in steps S2 and S5, when it is detected that it is difficult to insert or pull out the Larsen steel sheet piles, the steel sheet pile driving module starts the high-pressure water pump, and high-pressure water is ejected through the high-pressure water pipe to cut the soil at the bottom of the Larsen steel sheet piles to assist in inserting and pulling out the Larsen steel sheet piles.

[0026] Preferably, in step S3, the backfill soil in the area enclosed by the Larsen steel sheet piles and the fine sand in the sand-filled cofferdam are preferably filled by means of sand transportation pipeline flushing.

[0027] The specific method of adjusting the adjustable braces in real time according to the cofferdam filling module is as follows: the displacement and force sensors on the vertical rods and horizontal supports feedback information and the height of the backfill soil, and then the cofferdam filling module of the Internet of Things system controls the displacement of the vertical rods and the axial force of the horizontal supports; the vertical rods are continuously lifted according to the change of the backfill soil, and always ensure that the horizontal supports are above the backfill soil.

[0028] Specifically, the cofferdam filling module adjusts the operation area and filling speed of the backfill soil in real time. Based on the feedback information from the displacement and force sensors on the vertical rods and horizontal supports, and the water and soil pressure sensors on the L-shaped steel sheet piles, the cofferdam filling module of the Internet of Things system will adjust the filling operation area and filling speed of the backfill soil.

[0029] Preferably, in step S5, the L-shaped steel sheet piles are pulled out in the reverse order of driving.

[0030] In steps S5 and S6, if the island-building cofferdam is a temporary cofferdam, it is also necessary to clean the backfill soil, sand-filled cofferdam and wave-blocking blocks, clean the river channel, and restore the original ecological environment of the project site.

[0031] Preferably, the removed L-shaped steel sheet piles, steel beams, hoop structures, steel wales, adjustable braces, steel pipe piles, steel temporary bridges, guide frames and Internet of Things systems are recycled after recovery.

[0032] The beneficial effects of the present invention are as follows:

[0033] 1) The present invention adopts a structural form in which two rows of L-shaped steel sheet piles are arranged on the water-facing side of the cofferdam main body, and adjustable braces and high-pressure jet grouting piles are arranged between the two rows of L-shaped steel sheet piles, which greatly improves the stability and safety of the water-facing side of the cofferdam.

[0034] 2) In the present invention, high-pressure water pipes are provided on the inner wall of the tongue-and-groove of the L-shaped steel sheet piles. When it is difficult to insert and pull out the L-shaped steel sheet piles, the high-pressure water can be used to wash and cut the soil at the bottom of the L-shaped steel sheet piles to assist the L-shaped steel sheet piles to penetrate through the hard soil layer, which is beneficial to the rapid sinking or extraction of the L-shaped steel sheet piles, improves the insertion and extraction efficiency of the L-shaped steel sheet piles, and saves the construction period.

[0035] 3) The present invention adopts a guide frame to ensure the verticality of the driving of the L-shaped steel sheet piles, effectively preventing problems such as the overall axial position deviation and vertical inclination of the L-shaped steel sheet piles, and improving the construction efficiency and quality of the L-shaped steel sheet piles.

[0036] 4) The present invention adopts a hoop structure to realize the rapid connection between the L-shaped steel sheet piles and the steel beams above them, effectively improving the connection construction efficiency between the L-shaped steel sheet piles and the steel beams.

[0037] 5) The present invention adopts an adjustable brace to adjust the height of the vertical rod to control the position of the horizontal support. Through the axial force sensor and displacement sensor on the horizontal support, the deformation and stress conditions of the L-shaped steel sheet piles at the position where they are located can be measured in real time. By adjusting the height of the vertical rod and the axial force of the horizontal support, the deformation and stress of the L-shaped steel sheet piles can be effectively controlled, ensuring the stability and safety of the island-building cofferdam.

[0038] 6) The present invention uses precast plates with raised tongue-and-groove joints, which are connected by wedges and supplemented by steel hoops to quickly form a sand-filled cofferdam. Compared with traditional sand-filled pipe bags, it saves transportation and stacking time, improves the installation speed, and is convenient to demolish and reusable.

[0039] 7) The present invention sets anti-wave blocks on the water-facing side of the sand-filled cofferdam, which is convenient for construction, can prevent the scouring damage of the wave impact on the island-building cofferdam, and ensures the safety of the project construction.

[0040] 8) The present invention adopts an Internet of Things control system. Through the steel sheet pile driving module, the penetration construction parameters of the steel sheet pile are adjusted in a timely manner to control the pulling and driving efficiency and construction quality of the Larsen steel sheet pile; through the cofferdam filling module, the refined management and control of the cofferdam filling are realized, ensuring the safety of the island-building cofferdam project and improving the construction efficiency of the island-building cofferdam.

[0041] 9) The present invention uses a steel temporary bridge for the walking and transportation of people, materials and machinery, greatly reducing the damage of the project construction to the natural environment around the island-building cofferdam, facilitating the restoration of the original ecological environment of the site after the construction, conforming to the green and environmental protection construction concept, and having significant social benefits.

[0042] 10) The Larsen steel sheet piles, steel beams, hoop structures, steel wales, adjustable braces, steel pipe piles, steel temporary bridges, guide frames and Internet of Things systems removed in the present invention can all be recycled in similar projects, improving the popularization of the invention, reducing the practice cost of the new method, and at the same time conforming to the low-carbon and sustainable construction concept. Description of the Drawings

[0043] Figure 1 It is a sectional view of an island-building cofferdam with steel sheet piles affected by tides;

[0044] Figure 2 It is a lap joint diagram of Larsen steel sheet piles;

[0045] Figure 3 It is a lap joint diagram of the raised tongue-and-groove precast plates of the sand-filled cofferdam.

[0046] In the figure: Larsen steel sheet pile 1; high-pressure water pipe 2; steel beam 3; hoop structure 4; steel wale 5; adjustable brace 6; vertical rod 6-1; horizontal support 6-2; water and soil pressure sensor 7; high-pressure jet grouting pile 8; backfill soil 9; steel pipe pile 10; steel temporary bridge 11; guide frame 12; sand-filled cofferdam 13; raised tongue-and-groove precast plate 13-1; fine sand material 13-2; anti-wave block 14; Detailed Embodiments

[0047] The present invention will be further described below in conjunction with embodiments. The description of the following embodiments is only for helping to understand the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several modifications can still be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0048] Embodiment 1

[0049] As Figures 1 to 3 shown, the tidal influence steel sheet pile island-building cofferdam includes a cofferdam main body, a water-facing side anti-scouring system and an Internet of Things control system; the cofferdam main body includes a Larssen steel sheet pile 1, a steel beam 3, a hoop structure 4, a steel waling 5, an adjustable support 6, a water and soil pressure sensor 7, a high-pressure jet grouting pile 8 and backfill soil 9.

[0050] Both sides of the Larssen steel sheet pile 1 are tongue-and-groove, and are connected to each other by tongue-and-groove; the high-pressure water pipe 2 is fixedly installed on the inner wall of the tongue-and-groove of the Larssen steel sheet pile 1, both ends are open, the upper port is connected to a high-pressure water pump, and the lower port sprays high-pressure water to cut the soil at the bottom of the Larssen steel sheet pile 1.

[0051] The Larssen steel sheet pile 1 is set perpendicular to the horizontal elevation; the Larssen steel sheet piles are tightly connected by a steel waling 5; the Larssen steel sheet pile 1 and the upper steel beam 3 are quickly connected through a hoop structure 4; the adjustable support 6 is fixedly connected to the middle of the steel beam 3, including a vertical rod 6-1 and a horizontal support 6-2; displacement and force sensors are provided on both the vertical rod 6-1 and the horizontal support 6-2, and the lengths of the vertical rod 6-1 and the horizontal support 6-2 can be freely adjusted by hydraulic components; both ends of the horizontal support 6-2 abut against the Larssen steel sheet pile 1;

[0052] The water and soil pressure sensor 7 is fixedly installed on the Larssen steel sheet pile 1;

[0053] The backfill soil 9 is filled in the enclosed area of the Larssen steel sheet pile 1, and the top surface is flush with the top of the steel beam 3; a settlement monitoring sensor is arranged on the top surface of the backfill soil 9; a steel temporary bridge 11 is erected on the upper part of the steel pipe pile 10 and is parallel to the Larssen steel sheet pile 1; the guide frame 12 can be erected on the steel temporary bridge 11; the Larssen steel sheet pile 1 is vertically driven in through the guide frame 12; vertical sensors are arranged on the guide frame 12;

[0054] The water-facing side anti-scouring system includes a sand-filled cofferdam 13 and anti-wave blocks 14; the sand-filled cofferdam 13 is assembled into a rectangle by four high-raised tongue-and-groove precast slabs 13-1 and is filled with fine sand material 13-2 inside; the sand-filled cofferdam 13 is installed on the water-facing side of the Larssen steel sheet pile 1; the anti-wave blocks 14 are arranged on the water-facing side of the sand-filled cofferdam 13. The anti-wave blocks 14 are made of concrete material, are regularly piled up according to the design requirements, and the top is slightly lower than the top of the high-raised tongue-and-groove precast slab 13-1 and is set in a slope shape.

[0055] The Internet of Things control system includes a steel sheet pile driving module and a cofferdam filling module; the steel sheet pile driving module is connected to the guide frame 12 and the high-pressure water pump; through the feedback information of the vertical sensors on the guide frame 12, the steel sheet pile driving module will control the verticality of the La Sen steel sheet pile 1 during driving; when it is detected that it is difficult to insert or pull out the La Sen steel sheet pile 1, the steel sheet pile driving module will start the high-pressure water pump, and high-pressure water will be sprayed through the high-pressure water pipe 2 to cut the soil at the bottom of the La Sen steel sheet pile 1 to assist in the insertion and extraction of the La Sen steel sheet pile 1.

[0056] The cofferdam filling module is connected to the vertical rod 6-1, the horizontal support 6-2, the water and soil pressure sensor 7 on the La Sen steel sheet pile 1, and the settlement monitoring sensor on the top surface of the backfill soil 9; through the feedback information of the displacement and force sensors on the vertical rod 6-1 and the horizontal support 6-2 and the height of the backfill soil, the cofferdam filling module will control the displacement and axial force of the vertical rod 6-1 and the horizontal support 6-2; through the feedback information of the displacement and force sensors on the vertical rod 6-1 and the horizontal support 6-2 and the water and soil pressure sensor 7 on the La Sen steel sheet pile 1, the cofferdam filling module will adjust the backfill area and the backfill speed.

[0057] The lock of the La Sen steel sheet pile 1 is painted with a mixture of asphalt and butter ointment to reduce the frictional resistance during driving and improve the anti-seepage performance.

[0058] The La Sen steel sheet piles 1 enclose the contour of the cofferdam main body. Two rows of La Sen steel sheet piles 1 are arranged on the water-facing side of the cofferdam main body to improve the stability and safety of the water-facing side of the cofferdam; the steel wale 5 is welded to the upper part of the La Sen steel sheet pile 1 to make the La Sen steel sheet piles 1 closely connected and improve the overall stiffness.

[0059] The adjustable support 6 is installed between the two rows of La Sen steel sheet piles 1 on the water-facing side of the cofferdam main body and moves above the backfill soil 9. The height of the vertical rod 6-1 and the axial force of the horizontal support 6-2 can be adjusted through hydraulic components to control the deformation of the La Sen steel sheet pile 1. At the same time, the deformation and stress conditions of the La Sen steel sheet pile 1 at its location can be measured in real time according to the axial force sensor and displacement sensor on the horizontal support 6-2.

[0060] The high-pressure jet grouting pile 8 is arranged between the two rows of La Sen steel sheet piles 1 on the water-facing side of the cofferdam main body and is close to the La Sen steel sheet pile 1 on the offshore side of the cofferdam; the top surface of the high-pressure jet grouting pile 8 should be lower than the original ground at its construction location.

[0061] The fixed installation method of the water and soil pressure sensor 7 can be selected by welding the protective sleeve to the La Sen steel sheet pile 1. Its preferred installation form is that the bottom is flush with the current river bottom elevation, the bottom of the high-pressure jet grouting pile 8, and the bottom of the La Sen steel sheet pile 1 respectively.

[0062] The steel pipe pile 10 is rigidly connected to the steel temporary bridge 11. The steel pipe pile 10 serves as the lower pier structure of the steel temporary bridge 11 and supports the steel temporary bridge 11. The deck of the steel temporary bridge 11 is flush with the upper part of the steel beam 3.

[0063] The sand-filled cofferdam 13 is arranged on the water-facing side of the cofferdam main body and is inserted into the muddy soil layer. The connection of the heightened tongue-and-groove precast slab 13-1 is preferably a wedge connection. A number of steel hoops are sleeved on the outer side wall of the heightened tongue-and-groove precast slab 13-1 to tightly connect the four heightened tongue-and-groove precast slabs 13-1 to prevent sand leakage.

[0064] Embodiment 2

[0065] As another embodiment, the construction method of the tidal influence sheet pile island-building cofferdam in Embodiment 1 includes the following steps:

[0066] S1. Clear the site and measure and set points; construct the high-pressure jet grouting pile 8 using the triple-tube construction process; drive the steel pipe pile 10 and erect the steel temporary bridge 11; erect the guide frame 12 on the steel temporary bridge 11; connect the sheet pile driving module of the Internet of Things system.

[0067] S2. Insert the Larsen sheet pile 1 installed with the high-pressure water pipe 2, the water and soil pressure sensor 7, and coated with the asphalt and butter mixture ointment piece by piece according to the design. Through the sheet pile driving module of the Internet of Things system, control the verticality and driving speed of the Larsen sheet pile 1 during driving; hoist and place the steel waling 5 and weld it after keeping it on the same axis as the Larsen sheet pile 1; use the hoop structure 4 to tightly connect the steel beam 3 and the Larsen sheet pile 1; install the adjustable support 6 under the steel beam 3; connect the cofferdam filling module of the Internet of Things system; through the feedback information of the vertical sensor on the guide frame 12, the sheet pile driving module will control the verticality of the Larsen sheet pile 1 during driving; in steps S2 and S6, when it is detected that the Larsen sheet pile 1 is difficult to insert and pull out, the sheet pile driving module will start the high-pressure water pump, and the high-pressure water will be sprayed through the high-pressure water pipe 2 to cut the soil at the bottom of the Larsen sheet pile 1 to assist in the insertion and extraction of the Larsen sheet pile 1.

[0068] S3. After the driving of the Larsen sheet pile 1 near the water area is completed, wait for the low tide level and install the sand-filled cofferdam 13. First, insert the four heightened tongue-and-groove precast slabs 13-1 into the muddy soil layer, sleeve a number of steel hoops on the outer side wall, and tightly connect the four heightened tongue-and-groove precast slabs 13-1.

[0069] S4. Synchronously fill the backfill soil 9 in the area enclosed by the Larsen sheet pile 1 and the fine sand material 13-2 in the sand-filled cofferdam 13. According to the cofferdam filling module of the Internet of Things system, adjust the displacement and axial force of the vertical rod 6-1 and the horizontal support 6-2 in real time, as well as the operation area and filling speed of the backfill soil 9. The backfill soil 9 in the area enclosed by the Larsen sheet pile 1 and the fine sand material 13-2 in the sand-filled cofferdam 13 are preferably filled by the method of filling with a sand transportation pipeline.

[0070] The real-time adjustment of the displacement and axial force of the vertical rod 6-1 and the horizontal support 6-2 is specifically carried out by the feedback information of the displacement and force sensors on the vertical rod 6-1 and the horizontal support 6-2, as well as the backfill height. The cofferdam filling module of the Internet of Things system will control the displacement of the vertical rod 6-1 and the axial force of the horizontal support 6-2 to ensure that the stress and deformation of the Larssen sheet pile 1 are within the safe range; the vertical rod 6-1 is continuously lifted according to the change of the backfill soil 9, always ensuring that the horizontal support 6-2 is above the backfill soil 9;

[0071] The operation area and filling speed of the backfill soil 9 are specifically adjusted by the feedback information of the displacement and force sensors on the vertical rod 6-1 and the horizontal support 6-2, and the water and soil pressure sensor 7 on the Larssen sheet pile 1. The cofferdam filling module of the Internet of Things system will adjust the filling operation area and filling speed of the backfill soil 9 to ensure that the stress and deformation of the Larssen sheet pile 1 are within the safe range, and further ensure the overall stability of the cofferdam project.

[0072] S5. After the fine sand material 13-2 in the sand-filled cofferdam 13 is filled to the design elevation, after ensuring that the height of the backfill soil 9 between the two Larssen sheet piles 1 on the water-facing side of the cofferdam main body is the same, suspend the filling of the backfill soil 9 between the two Larssen sheet piles 1, and continue to fill the backfill soil 9 in other areas of the cofferdam until the design elevation; synchronously, install the wave-dissipating blocks 14 on the water-facing side of the sand-filled cofferdam 13 according to the design requirements.

[0073] S6. After the construction of the backfill soil 9 in other areas of the cofferdam is completed, remove the Internet of Things system, and then remove the guide frame 12, adjustable support 6, hoop structure 4, steel beam 3, steel waling 5 and Larssen sheet pile 1 in turn. Continue to backfill the soil in the gap formed between the two Larssen sheet piles 1 on the water-facing side of the cofferdam main body and at the place where the Larssen sheet pile 1 is pulled out until the design elevation; the Larssen sheet pile 1 is pulled out in the reverse order of driving.

[0074] S7. After all the island-building cofferdam and related projects are constructed, remove the steel pipe piles 10 and steel temporary bridges 11. If the island-building cofferdam is a temporary cofferdam, it is also necessary to clean up the backfill soil 9, sand-filled cofferdam 13 and wave-dissipating blocks 14, clean the river channel, and restore the original ecological environment of the project site; the removed Larssen sheet pile 1, steel beam 3, hoop structure 4, steel waling 5, adjustable support 6, steel pipe piles 10, steel temporary bridges 11, guide frame 12 and Internet of Things system can all be recycled in similar projects.

Claims

1. A construction method for a steel sheet pile island cofferdam affected by tides, characterized in that: It includes a cofferdam main body, a water-facing side anti-erosion system, and an Internet of Things control system; the cofferdam main body includes Larssen sheet piles (1), steel beams (3), adjustable braces (6), and water and soil pressure sensors (7); On the water-facing side of the cofferdam main body, there are two rows of Larssen sheet piles (1), and each row of Larssen sheet piles (1) is interlocked through tongue-and-groove joints; high-pressure water pipes (2) are provided on the inner walls of the tongue-and-groove joints of the Larssen sheet piles (1); the water and soil pressure sensors (7) are fixed on the Larssen sheet piles (1); the Larssen sheet piles (1) are connected to the upper steel beam (3); the top of the adjustable brace (6) is connected to the steel beam (3), and the adjustable brace (6) braces the two rows of Larssen sheet piles (1); backfill soil (9) is filled within the area enclosed by the Larssen sheet piles (1), and settlement monitoring sensors are provided on the top surface of the backfill soil (9); It further includes steel pipe piles (10), and a guide frame (12) for driving the Larssen sheet piles (1) is provided on the steel pipe piles (10); The water-facing side anti-erosion system includes a sand-filled cofferdam (13) and anti-wave blocks (14); the sand-filled cofferdam (13) is provided on the water-facing side of the Larssen sheet piles (1); the anti-wave blocks (14) are provided on the water-facing side of the sand-filled cofferdam (13); The Internet of Things control system includes a sheet pile driving module and a cofferdam filling module; the sheet pile driving module is connected to the guide frame (12) and a high-pressure water pump; the cofferdam filling module is connected to the adjustable brace (6), the water and soil pressure sensors (7), and the settlement monitoring sensors; The locking joints of the Larssen sheet piles (1) are painted with a mixture of asphalt and butter ointment; the Larssen sheet piles (1) enclose to form the contour of the cofferdam main body; the upper ports of the high-pressure water pipes (2) are connected to a high-pressure water pump; the Larssen sheet piles (1) are arranged perpendicular to the horizontal elevation; the Larssen sheet piles are connected through steel wales (5); the steel wales (5) are welded to the upper parts of the Larssen sheet piles (1); The Larssen sheet piles (1) are connected to the upper steel beam (3) through a hoop structure (4); the adjustable brace (6) includes a vertical rod (6-1) and a horizontal support (6-2); displacement and force sensors are provided on both the vertical rod (6-1) and the horizontal support (6-2), and hydraulic components for adjusting the length are provided on both the vertical rod (6-1) and the horizontal support (6-2); the horizontal support (6-2) braces between the two rows of Larssen sheet piles (1); It further includes high-pressure jet grouting piles (8), and the high-pressure jet grouting piles (8) are arranged between the two rows of Larssen sheet piles (1) on the water-facing side of the cofferdam main body and are close to one row of Larssen sheet piles (1) on the offshore side of the cofferdam; the top surface of the high-pressure jet grouting piles (8) is lower than the original ground at the construction location; This method includes the following steps: S1. Clear the site, measure and set points; construct high-pressure jet grouting piles (8); drive steel pipe piles (10), build a steel temporary bridge (11) and erect a guide frame (12); connect the sheet pile driving module; S2. Assist in driving Larssen sheet piles (1) provided with high-pressure water pipes (2) and water and soil pressure sensors (7) through the sheet pile driving module; weld steel wales (5); use a hoop structure (4) to connect the steel beam (3) and the Larssen sheet piles (1); install an adjustable brace (6) under the steel beam (3) and connect the cofferdam filling module; S3. Build a sand-filled cofferdam (13) in the silt layer; simultaneously fill the backfill soil (9) within the area enclosed by the Larssen sheet piles (1) and the fine and medium sand material (13-2) within the sand-filled cofferdam (13), and adjust the backfilling speed of the adjustable support frame (6) and the backfill soil (9) in real time according to the cofferdam filling module; S4. After the height of the backfill soil (9) between the two rows of Larssen sheet piles (1) on the water-facing side of the cofferdam main body reaches the design elevation of the fine and medium sand material (13-2), suspend the backfilling, and fill the backfill soil (9) in other areas of the cofferdam to the design elevation; install wave-breaking blocks (14) on the water-facing side of the sand-filled cofferdam (13); S5. Remove the Internet of Things control system, guide frame (12), adjustable support frame (6), hoop structure (4), steel beam (3), steel waling (5), and Larssen sheet piles (1) in sequence, and backfill the backfill soil (9) until the design elevation; S6. After the island-building cofferdam and related projects are all constructed, remove the steel pipe piles (10) and steel temporary bridge (11).

2. The construction method of the steel sheet pile island cofferdam affected by tides according to claim 1, wherein: The water and soil pressure sensor (7) is welded to the Larssen sheet pile (1) through a protective sleeve, and the bottom of the water and soil pressure sensor (7) is flush with the elevation of the current river bottom, the bottom of the high-pressure jet grouting pile (8), and the bottom of the Larssen sheet pile (1) respectively.

3. The construction method of the steel sheet pile island cofferdam affected by tides according to claim 1, wherein: The top surface of the backfill soil (9) is flush with the top of the steel beam (3); a steel temporary bridge (11) is erected on the upper part of the steel pipe pile (10), and the guide frame (12) is erected on the steel temporary bridge (11); a Larssen sheet pile (1) is vertically driven below the guide frame (12); the steel pipe pile (10) is parallel to the Larssen sheet pile (1); the guide frame (12) is provided with a vertical sensor, the steel pipe pile (10) is rigidly connected to the steel temporary bridge (11), and the steel pipe pile (10) is the lower pier structure of the steel temporary bridge (11); the bridge deck of the steel temporary bridge (11) is flush with the upper part of the steel beam (3).

4. The construction method of the steel sheet pile island cofferdam affected by tides according to claim 3, characterized in that: The sand-filled cofferdam (13) includes a heightened tongue-and-groove precast slab (13-1), and four heightened tongue-and-groove precast slabs (13-1) are assembled into a rectangle, and the rectangle is filled with fine and medium sand material (13-2); the sand-filled cofferdam (13) is arranged on the water-facing side of the cofferdam main body and is inserted into the silt layer; the heightened tongue-and-groove precast slab (13-1) is in a wedge-shaped connection; several steel hoops are sleeved on the outer side wall of the heightened tongue-and-groove precast slab (13-1); The wave-breaking block (14) is made of concrete material, the top of the wave-breaking block (14) is lower than the top of the heightened tongue-and-groove precast slab (13-1), and the wave-breaking block (14) is in a slope shape.

5. The construction method of the steel sheet pile island-building cofferdam affected by tides according to claim 4, characterized in that: In step S2, through the feedback information of the vertical sensor on the guide frame (12), the steel sheet pile driving module controls the verticality of the Larssen sheet pile (1) during driving; in steps S2 and S5, when it is detected that the Larssen sheet pile (1) is difficult to insert and pull out, the steel sheet pile driving module starts the high-pressure water pump, and high-pressure water is ejected through the high-pressure water pipe (2) to cut the soil at the bottom of the Larssen sheet pile (1) to assist in the insertion and extraction of the Larssen sheet pile (1).

6. The construction method of the steel sheet pile island cofferdam affected by tides according to claim 5, characterized in that: In step S3, the backfill soil (9) within the area enclosed by the Larssen sheet piles (1) and the fine and medium sand material (13-2) within the sand-filled cofferdam (13) are filled by means of sand blowing through a sand pipeline; The specific method for adjusting the adjustable support (6) in real time according to the cofferdam filling module is as follows: the displacement and force sensor feedback information on the vertical rod (6-1) and the horizontal support (6-2) and the height of the backfill soil (9) are used, and then the displacement of the vertical rod (6-1) and the axial force of the horizontal support (6-2) are controlled by the cofferdam filling module of the Internet of Things control system; the vertical rod (6-1) is continuously lifted according to the change of the backfill soil (9), and it is always ensured that the horizontal support (6-2) is above the backfill soil (9). The specific operation of the cofferdam filling module for adjusting the operation area and filling speed of the backfill soil (9) in real time is as follows: the displacement and force sensors on the vertical rod (6-1) and the horizontal support (6-2) and the water and soil pressure sensors (7) on the sheet pile (1) feedback information, and the cofferdam filling module of the Internet of Things control system will adjust the filling operation area and filling speed of the backfill soil (9).

7. The construction method of the steel sheet pile island cofferdam affected by tides according to claim 6, characterized in that: In the step S5, the sheet pile (1) is pulled out in the reverse order of pile driving. In the steps S5 and S6, if the island-building cofferdam is a temporary cofferdam, it is also necessary to clean the backfill soil (9), the sand-filled cofferdam (13) and the wave-proof blocks (14), clean the river channel, and restore the original ecological environment of the project site.

8. The construction method of the steel sheet pile island cofferdam affected by tides according to claim 7, characterized in that: The removed sheet pile (1), steel beam (3), hoop structure (4), steel waling (5), adjustable support (6), steel pipe pile (10), steel temporary bridge (11), guide frame (12) and the Internet of Things control system are recycled after recovery.

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