Lassen steel sheet pile cofferdam construction method suitable for deep water area

Abstract

The invention relates to the technical field of Larsen steel sheet pile construction, and discloses a Larsen steel sheet pile cofferdam construction method suitable for a deepwater area, which comprises the following construction steps: 1) arranging a construction platform; (2) four positioning piles are driven into the construction position to form a construction area; 3) arranging a guide frame in the construction area, wherein the guide frame is provided with a guide arm; (4) a plurality of Larsen steel sheet piles are driven along the guide arms, the bottoms of the Larsen steel sheet piles extend into the solid soil layer, and adjacent Larsen steel sheet piles are arranged in a sealed mode; (5) enclosing purlins are arranged on the pile rows, and steel supports are arranged between the enclosing purlins to form an inner supporting structure; (6) water and sludge in the construction area are sucked till the solid soil layer is exposed at the bottom, and the Larsen steel sheet pile cofferdam is formed by the multiple Larsen steel sheet piles and the multiple inner supporting structures; the bottoms of the Larsen steel sheet piles extend to a solid soil layer and are arranged in a sealed mode, and a plurality of inner supporting structures are arranged, so that the water stopping performance of the cofferdam is improved, and meanwhile the stability and the water flow impact resistance are enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of Larsen steel sheet pile construction, in particular to a Larsen steel sheet pile cofferdam construction method suitable for deep water areas. Background Art

[0002] In the foundation construction process of water conservancy projects in deep water areas, steel sheet pile cofferdam, as a common construction technology, plays a vital role.

[0003] At present, traditional single-row steel sheet piles are prone to deformation and leakage in deep water environments, and cannot meet the strict requirements for the water-stopping properties of cofferdams in deep water construction. This is mainly because the water pressure in deep water areas is relatively high, and single-row steel sheet piles cannot withstand the high water pressure, which leads to leakage in the cofferdam, thereby affecting the normal progress of construction. In addition, complex geological conditions will aggravate this problem and further increase construction risks.

[0004] Although double-row steel sheet pile structures are also used in the existing technology, they mostly adopt conventional connection methods and are not fully optimized in combination with the characteristics of deep water areas. This simple double-row structure still has the problem of insufficient water-stopping performance when facing the complex hydrological and geological conditions in deep water areas.

[0005] In addition, the conventional double-row steel sheet pile structure also leads to low construction efficiency and high cost; the conventional connection method makes it difficult to ensure the sealing between the steel sheet piles, and cannot effectively prevent the infiltration of water. At the same time, during the construction process, due to the lack of targeted design, more manpower, material resources and time are required to solve the water-stopping problem, thereby increasing construction costs and construction period. Summary of the Invention

[0006] The purpose of the present invention is to provide a Larsen steel sheet pile cofferdam construction method suitable for deep water areas, aiming to solve the problem of insufficient water-stopping performance of Larsen steel sheet pile cofferdams in deep water areas in the prior art.

[0007] The present invention is implemented as follows: a Larsen steel sheet pile cofferdam construction method suitable for deep water areas includes the following construction steps: 1) Arrange a construction platform in the deep water area; 2) Drive four positioning piles into the construction position in the deep water area. The four positioning piles are arranged around each other at intervals to form a construction area. 3) Arranging a guide frame in the construction area, wherein the guide frame has a plurality of horizontally arranged guide arms, wherein the plurality of guide arms are sequentially connected to form a square shape, and the guide arms are connected to adjacent positioning piles, and the plurality of guide arms are arranged around the periphery of the construction area; 4) Driving multiple Larsen steel sheet piles in sequence along the sides of the multiple guide arms. The multiple Larsen steel sheet piles are arranged around the periphery of the construction area to form four linear pile rows. The bottoms of the Larsen steel sheet piles extend into the solid soil layer, and adjacent Larsen steel sheet piles are sealed. 5) A transversely arranged perimeter purlin is provided on two oppositely arranged pile rows. The perimeter purlin is welded to a plurality of Larsen steel sheet piles of the pile row. A transversely arranged steel support is provided between the two perimeter purlins. The ends of the steel support are respectively connected to the perimeter purlins. The steel support and the two perimeter purlins form an internal support structure. 6) During the process of pumping water from the construction area and clearing silt from the construction area, the construction step 5) is repeated until the solid soil layer is exposed at the bottom of the construction area, and a plurality of internal support structures are formed in the construction area. The plurality of internal support structures are arranged in sequence along the height direction of the construction area, and the plurality of Larsen steel sheet piles and the plurality of internal support structures form a Larsen steel sheet pile cofferdam.

[0008] Furthermore, in the construction step 1), the construction platform is formed by splicing a plurality of pontoons floating on the water surface, and a plurality of insertion rods are provided on the construction platform, and the plurality of insertion rods are inserted into the solid soil layer at the bottom of the deep water area to fix the construction platform on the water surface.

[0009] Furthermore, in the construction step 2), a pile driver is arranged on the construction platform. The pile driver is equipped with a vibrating hammer, and the vibrating hammer is used to drive the positioning piles into the construction location.

[0010] Furthermore, in the construction step 2), a positioning corbel is provided on the positioning pile, and a positioning platform is provided on the top of the positioning corbel; in the construction step 3), the guide arm is placed on the positioning platform of the positioning corbel and fixedly connected to the positioning corbel by welding.

[0011] Furthermore, in the construction step 4), both sides of the Larsen steel sheet piles have curved edges, and the curved edges enclose a curved groove. Between adjacent Larsen steel sheet piles, the curved edges are embedded in the curved groove, so that the adjacent Larsen steel sheet piles are connected as a whole, and the adjacent Larsen steel sheet piles are sealed.

[0012] Furthermore, in the construction step 4), the Larsen steel sheet pile includes a straight segment, and both sides of the straight segment have inclined segments, the inner ends of the inclined segments are butted against the ends of the straight segment, and the outer ends of the inclined segments form the curved edges; adjacent Larsen steel sheet piles are arranged in opposite staggered positions so that the curved edges are embedded in the curved grooves.

[0013] Furthermore, in the construction step 4), a corner position is formed between adjacent rows of piles, and a corner steel sheet pile is provided at the corner position. The corner steel sheet pile is bent at a right angle, and both sides of the corner steel sheet pile have curved hook edges; the two sides of the corner steel sheet pile are respectively connected to the Larsen steel sheet piles of the adjacent pile row, the hook edges are embedded in the curved groove, and the corner steel sheet pile and the Larsen steel sheet pile are sealed.

[0014] Furthermore, in the construction step 5), the assembled Larsen steel sheet piles are provided with supporting corbels, the tops of the supporting corbels have supporting platforms, the perimeter purlins are fixed on a plurality of supporting platforms, and are fixedly connected to a plurality of the Larsen steel sheet piles.

[0015] Furthermore, in the construction step 4), the end of the curved edge is recessed inward to form a recessed groove, and the recessed groove is filled with an elastic sealing strip, which is movably arranged in the recessed groove and extends to the outside of the recessed groove to form an outer section, and side sections are formed on both sides of the outer section, and the two side sections are respectively clamped on both sides of the curved edge; The sealing strip, the outer section and the two side sections are integrally formed. When the curved edge is embedded in the curved groove, the outer section presses against the inner side wall of the curved groove to compress and deform the outer section and the sealing strip. The sealing strip is fixed in the recessed groove, and the two side sections are squeezed and clamped on both sides of the curved edge.

[0016] Furthermore, in the construction step 4), a deformation gap is provided between the sealing strip and the bottom of the recessed groove, the outer section protrudes outward to form a raised portion, and a hard guide strip is provided in the sealing strip. The guide strip is wrapped in the sealing strip and extends along the depth direction of the recessed groove. The guide strip passes through the outer section and extends into the raised portion. When the curved edge is embedded in the curved groove, the protrusion abuts against the inner wall of the curved groove, the outer section and the sealing strip are compressed and deformed, and the guide strip guides the sealing strip to compress and deform toward the deformation gap until the deformation gap is filled.

[0017] Compared with the existing technology, the present invention provides a Larsen steel sheet pile cofferdam construction method suitable for deep water areas. First, after arranging a construction platform in the deep water area, four positioning piles arranged at intervals are driven in to form a construction area, providing precise positioning for subsequent construction. The step of arranging the guide frame ensures that the Larsen steel sheet piles can be accurately positioned in sequence, effectively improving construction efficiency.

[0018] Secondly, because the Larsen steel sheet piles are driven into the soil along the guide frame, their bottoms penetrate deep into the solid soil layer and are in close contact with the foundation. The sealing arrangement between adjacent piles blocks the leakage path of water between the piles, thus forming a reliable water-stop barrier at the bottom and sides of the cofferdam. This greatly enhances the water-stopping performance of the cofferdam, effectively preventing water from deep water areas from seeping into the construction area, and ensuring that subsequent construction can be carried out in a relatively dry environment.

[0019] Finally, the internal support structure formed by the purlins and steel supports strengthens the overall stability of the cofferdam, enabling it to better withstand the impact of water flow, avoid deformation or displacement of the cofferdam caused by impact, and further ensure the water-stopping performance of the cofferdam; and, as the water body is pumped out and the silt is cleared, the internal support structure is repeatedly set until the solid soil layer is exposed. Multiple internal support structures are arranged in sequence along the height direction, and together with the Larsen steel sheet piles, they form a stable cofferdam system, providing reliable protection for deep-water engineering construction, reducing construction risks and costs, and having significant economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic flow chart of a Larsen steel sheet pile cofferdam construction method applicable to deep water areas provided by the present invention; Figure 2 It is a plan view of the construction area provided by the present invention; Figure 3 This is a schematic diagram of the main view of the Larsen steel sheet pile provided by the present invention; Figure 4 This is a simplified schematic diagram of the corner steel sheet pile provided by the present invention; Figure 5 It is a simplified schematic diagram of the positioning pile provided by the present invention; Figure 6 is a cross-sectional schematic diagram of the curved edge and the sealing strip provided by the present invention; In the figure: positioning pile 100, construction area 101, guide arm 102, positioning bracket 103, positioning platform 104; Larsen steel sheet pile 200, curved edge 201, curved groove 202, straight section 203, inclined section 204; Pile row 300, perimeter purlin 301, steel support 302, corner steel sheet pile 303, hook 304; Sealing strip 400 , outer section 401 , side section 402 , deformation spacer 403 , raised portion 404 , guide strip 405 . DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0022] The implementation of the present invention is described in detail below with reference to specific embodiments.

[0023] The same or similar numbers in the drawings of this embodiment correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "up", "down", "left", "right", etc. indicate directions or positional relationships, they are based on the directions or positional relationships shown in the drawings. This is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0024] Reference Figure 1-6 The figure shows a preferred embodiment of the present invention.

[0025] The Larsen steel sheet pile cofferdam construction method, suitable for deepwater areas, includes the following construction steps: 1) Arrange a construction platform in the deep water area; 2) Four positioning piles 100 are driven into the construction position in the deep water area. The four positioning piles 100 are arranged in a circle at intervals, and the four positioning piles 100 enclose a construction area 101; 3) Arrange a guide frame in the construction area 101. The guide frame has multiple horizontally arranged guide arms 102. The multiple guide arms 102 are connected in sequence to form a square shape. The guide arms 102 are connected to adjacent positioning piles 100. The multiple guide arms 102 are arranged around the periphery of the construction area 101. 4) Multiple Larsen steel sheet piles 200 are driven in sequence along the sides of the multiple guide arms 102. The multiple Larsen steel sheet piles 200 are arranged around the periphery of the construction area 101 to form four linear pile rows 300. The bottoms of the Larsen steel sheet piles 200 extend into the solid soil layer, and adjacent Larsen steel sheet piles 200 are sealed. 5) A transversely arranged perimeter purlin 301 is provided on two opposing pile rows 300. The perimeter purlin 301 is welded to the multiple Larsen steel sheet piles 200 of the pile row 300. A transversely arranged steel support 302 is provided between the two perimeter purlins 301. The ends of the steel support 302 are respectively connected to the perimeter purlin 301. The steel support 302 and the two perimeter purlins 301 form an internal support structure. 6) During the process of pumping out the water in the construction area 101 and clearing the silt in the construction area 101, the construction step 5) is repeated until the solid soil layer is exposed at the bottom of the construction area 101, and multiple internal support structures are formed in the construction area 101. The multiple internal support structures are arranged in sequence along the height direction of the construction area 101, and the multiple Larsen steel sheet piles 200 and the multiple internal support structures form a Larsen steel sheet pile 200 cofferdam.

[0026] The above-mentioned cofferdam construction method using Larsen steel sheet piles 200, which is suitable for deep-water areas, first arranges a construction platform in the deep-water area, and then drives four positioning piles 100 arranged in a spaced-apart manner to form a construction area 101, thereby providing precise positioning for subsequent construction. The step of arranging the guide frame ensures that the Larsen steel sheet piles 200 can be accurately positioned in sequence, effectively improving construction efficiency.

[0027] Secondly, because the Larsen steel sheet piles 200 are driven into the soil layer according to the guide frame, their bottoms penetrate deep into the solid soil layer and are in close contact with the foundation. The sealing arrangement between adjacent piles blocks the leakage path of water between the piles, thereby forming a reliable water-stopping barrier at the bottom and sides of the cofferdam. This greatly enhances the water-stopping performance of the cofferdam, effectively preventing water from deep water areas from seeping into the construction area 101, and ensuring that subsequent construction can be carried out in a relatively dry environment.

[0028] Finally, the internal support structure formed by the purlin 301 and the steel support 302 strengthens the overall stability of the cofferdam, enabling it to better resist the impact of water flow, avoid deformation or displacement of the cofferdam caused by impact, and further ensure the water-stopping performance of the cofferdam; and, as the water body is pumped out and the silt is cleared, the internal support structure is repeatedly set until the solid soil layer is exposed. Multiple internal support structures are arranged in sequence along the height direction, and together with the Larsen steel sheet piles 200, they form a stable cofferdam system, providing reliable protection for deep-water engineering construction, reducing construction risks and costs, and having significant economic and social benefits.

[0029] In this embodiment, in construction step 1), the construction platform is formed by splicing multiple pontoons floating on the water surface. The construction platform is provided with multiple insertion rods, which are inserted into the solid soil layer at the bottom of the deep water area to fix the construction platform on the water surface.

[0030] In this way, a stable working platform is provided for subsequent construction, ensuring the smooth progress of the construction process. At the same time, the pontoon splicing method makes it convenient to adjust the size and shape of the platform according to construction needs, and the insertion of rods into the solid soil layer effectively enhances the stability of the platform and prevents the platform from displacement or shaking under the impact of water flow.

[0031] In this embodiment, in construction step 2), a pile driver is arranged on the construction platform. The pile driver is equipped with a vibrating hammer, and the vibrating hammer is used to drive the positioning piles 100 into the construction location.

[0032] In this way, the positioning pile 100 can be accurately driven into the designated position in a shorter time, and the use of the vibratory hammer can make the positioning pile 100 more firmly inserted into the deep water stratum, providing an accurate positioning reference for the subsequent cofferdam construction, ensuring the smooth progress of the entire construction process.

[0033] In this embodiment, in construction step 2), a positioning corbel 103 is provided on the positioning pile 100, and a positioning platform 104 is provided on the top of the positioning corbel 103; in construction step 3), the guide arm 102 is placed on the positioning platform 104 of the positioning corbel 103 and is fixedly connected to the positioning corbel 103 by welding.

[0034] By setting the positioning bracket 103 and the positioning platform 104, an accurate installation position and a stable support foundation are provided for the guide arm 102, and the welding fixation enhances the connection strength between the guide arm 102 and the positioning bracket 103, ensuring the overall stability of the guide frame, thereby ensuring that the Larsen steel sheet pile 200 can be accurately driven along the guide arm 102, thereby improving construction accuracy.

[0035] In this embodiment, in construction step 4), both sides of the Larsen steel sheet pile 200 have curved edges 201, which are respectively arranged in a curved manner. The curved edges 201 enclose a curved groove 202. Between adjacent Larsen steel sheet piles 200, the curved edges 201 are embedded in the curved groove 202, so that the adjacent Larsen steel sheet piles 200 are connected as a whole, and the adjacent Larsen steel sheet piles 200 are sealed.

[0036] By embedding and cooperating the curved edge 201 and the curved groove 202, a reliable water-stopping line is formed to prevent water from leaking between the piles, thereby enhancing the overall water-stopping effect of the cofferdam and improving the water-stopping performance of the Larsen steel sheet pile 200 cofferdam in deep water areas.

[0037] In this embodiment, in construction step 4), the Larsen steel sheet pile 200 includes a straight segment 203, with inclined segments 204 on both sides of the straight segment 203. The inner ends of the inclined segments 204 are butted against the ends of the straight segment 203, and the outer ends of the inclined segments 204 form curved edges 201. Adjacent Larsen steel sheet piles 200 are arranged in opposite and staggered positions so that the curved edges 201 are embedded in the curved grooves 202.

[0038] In this way, when adjacent piles are arranged in opposite offset positions, the curved edge 201 and the curved groove 202 can be precisely fitted together, further improving the sealing and stability of the cofferdam and optimizing the stress-bearing performance of the cofferdam.

[0039] In this embodiment, in construction step 4), a corner position is formed between adjacent pile rows 300, and a corner steel sheet pile 303 is provided at the corner position. The corner steel sheet pile 303 is bent at a right angle, and both sides of the corner steel sheet pile 303 have curved hooks 304; the two sides of the corner steel sheet pile 303 are respectively connected to the Larsen steel sheet piles 200 of the adjacent pile row 300, the hooks 304 are embedded in the curved groove 202, and the corner steel sheet pile 303 and the Larsen steel sheet pile 200 are sealed.

[0040] The provision of corner steel sheet piles 303 solves the sealing problem of the cofferdam at the corners. The hook edge 304 is engaged with the curved groove 202 of the Larsen steel sheet pile 200, ensuring the water-stopping performance and integrity of the entire cofferdam at the corner position, making the cofferdam structure more solid, thereby adapting to the complex construction environment in deep water areas.

[0041] In this embodiment, in construction step 5), the assembled Larsen steel sheet piles 200 are provided with supporting corbels, the tops of the supporting corbels have supporting platforms, and the purlins 301 are fixed on multiple supporting platforms and fixedly connected to multiple Larsen steel sheet piles 200.

[0042] By providing supporting corbels and support platforms, a stable installation foundation is provided for the cofferdam 301, so that the cofferdam 301 can be firmly connected to the Larsen steel sheet piles 200. The formed internal support structure can effectively enhance the cofferdam's anti-deformation ability, improve the overall stability of the cofferdam, and enable it to better resist the impact of water flow.

[0043] In this embodiment, in construction step 4), the end of the curved edge 201 is recessed inward to form a recessed groove. The recessed groove is filled with an elastic sealing strip 400. The sealing strip 400 is movably arranged in the recessed groove and extends to the outside of the recessed groove to form an outer section 401. Side sections 402 are formed on both sides of the outer section 401. The two side sections 402 are respectively clamped on both sides of the curved edge 201. The sealing strip 400, the outer section 401, and the two side sections 402 are integrally formed. When the curved edge 201 is embedded in the curved groove 202, the outer section 401 presses against the inner side wall of the curved groove 202, causing the outer section 401 and the sealing strip 400 to be compressed and deformed. The sealing strip 400 is fixed in the recessed groove, and the two side sections 402 are squeezed and clamped on both sides of the curved edge 201.

[0044] When the curved edge 201 is embedded in the curved groove 202, the outer section 401 of the sealing strip 400 presses against the inner wall of the curved groove 202 and undergoes elastic deformation, filling the tiny gaps between the piles, further preventing the infiltration of water, greatly enhancing the sealing effect between adjacent Larsen steel sheet piles 200, and thereby strengthening the water-stopping performance of the cofferdam.

[0045] In this embodiment, in construction step 4), a deformable gap 403 is defined between the sealing strip 400 and the bottom of the recessed groove. The outer section 401 protrudes outward to form a raised portion 404. A hard guide strip 405 is provided in the sealing strip 400. The guide strip 405 is wrapped in the sealing strip 400 and extends along the depth direction of the recessed groove. The guide strip 405 passes through the outer section 401 and extends into the raised portion 404. When the curved edge 201 is embedded in the curved groove 202 , the raised portion 404 abuts against the inner wall of the curved groove 202 , the outer section 401 and the sealing strip 400 are compressed and deformed, and the guide strip 405 guides the sealing strip 400 toward the deformation gap 403 until the deformation gap 403 is filled.

[0046] By setting the guide strip 405, the sealing strip 400 has better guidance and stability when it is compressed and deformed, ensuring that the sealing strip 400 can evenly fill the deformation interval 403, further improving the sealing effect of the sealing strip 400, making the connection between the Larsen steel sheet piles 200 tighter, and the water-stopping performance of the cofferdam more reliable, thereby achieving high-performance water-stopping of the Larsen steel sheet pile 200 cofferdam in deep water areas.

[0047] Hereinafter, the technical solutions in the embodiments of the present invention will be described in detail, clearly and completely in combination with the embodiments of the present invention, so that the contents of the Larsen steel sheet pile cofferdam construction method applicable to deep water areas are easier to understand.

[0048] (1) Specific implementation and construction process 1. Construction preparation: Level the construction site, remove obstacles, check the appearance and locking quality of Larsen steel sheet piles, and correct unqualified piles; prepare positioning piles, guide frames and other components, and build a temporary power supply system to ensure normal power supply for construction. 2. Measurement and positioning: Use a total station to determine the cofferdam axis and pile position, set control piles and leveling base points, and hand over the measurement results to the construction team. 3. Construction platform construction: The customized pontoons are hoisted to the water surface in sections and assembled into an integral platform. They are fixed to the solid soil layer at the bottom of the deep water area by inserting rods to carry the pile driver and material transportation.

[0049] 4. Driving positioning piles: Use the reputable 349D pile driver with the reputable S500 vibratory hammer to drive the positioning piles into the designed position as a benchmark for subsequent construction. The positioning piles are equipped with positioning brackets to facilitate the subsequent installation of the guide frame. 5. Install the guide frame: Lay the guide frame on the positioning brackets of the four positioning piles, and tightly connect the positioning brackets through spot welding to prevent it from sinking or deforming during the piling process. 6. Drive the first row of Larsen steel sheet piles: After the guide frame is laid, drive multiple Larsen steel sheet piles in sequence along the side of the guide arm of the guide frame. Start by driving the Larsen steel sheet pile closest to the head positioning column, and then drive them in sequence along the guide frame to the end positioning pile. Control the verticality deviation of the pile body to no more than 1%, and the axis deviation to ±10cm.

[0050] 7. Drive the second row of Larsen steel sheet piles: Drive the second row of Larsen steel sheet piles parallel to the inside of the first row. The spacing between the two rows of piles is determined according to the design requirements. Use the same driving method to ensure that the lock joints are tightly connected.

[0051] 8. Installation of the first steel support: The Larsen steel sheet pile cofferdam support system has two purlin supports. The bracket stiffeners are welded on the inner wall of the Larsen steel sheet pile to position the bracket stiffeners. The purlins with specifications of 300×300×10×15 are hoisted. According to the design position, the bracket stiffeners are welded on the inner wall of the Larsen steel sheet pile to position the bracket stiffeners. Then the purlins are hoisted and welded for reinforcement. Among them, the flange plate of the purlin is flat against the steel waist beam on one side of the Larsen steel sheet pile, and the size is H300*300*10*15. 9. Pumping: Pump the water out of the double rows of Larsen steel sheet piles to lower the water level inside the piles. 10. Installation of the second steel support: Pump the water down to the installation elevation of the second purlin, install the second steel support, and form a complete multi-layer support system.

[0052] 11. Drainage and plugging: Continuously pump out water and check the water level in the cofferdam, seal any possible leakage points, and ensure a dry construction environment. 12. Clean up the silt: Remove the silt and debris in the cofferdam until the solid base is exposed.

[0053] 13. Foundation construction: Reinforced concrete foundation construction is carried out on the cleaned base, including tying steel bars, setting up formwork, pouring concrete and other processes. 14. Support removal: After the foundation construction is completed, the steel support should be removed symmetrically in the order of upper and lower to avoid excessive instantaneous stress release and structural deformation. 15. Dismantling of steel sheet pile cofferdam: Use a vibratory hammer to remove the Larsen steel sheet piles, starting from the position away from the corner piles, and proceed in the reverse order of piling. After removal, backfill the soil holes.

[0054] (2) Beneficial effects 1. The use of double-row Larsen steel sheet pile structure, combined with a reasonable connection method, significantly improves the water-stopping performance and water flow impact resistance of the cofferdam.

[0055] 2. The screen method construction technology is used to ensure the verticality and driving accuracy of Larsen steel sheet piles, reducing pile deformation and cumulative errors.

[0056] 3. The multi-layer support system effectively controls the deformation of the cofferdam, improving the safety and stability of construction in deep water areas.

[0057] 4. The rational design of the pontoon construction platform makes the equipment easy to transport and install, thus adapting to the complex construction environment in deep water areas.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. The Larsen steel sheet pile cofferdam construction method suitable for deep water areas is characterized by: The construction steps include: 1) Arrange a construction platform in the deep water area; 2) Drive four positioning piles into the construction position in the deep water area, and arrange the four positioning piles in a circle at intervals to form a construction area; 3) Arranging a guide frame in the construction area, wherein the guide frame has a plurality of horizontally arranged guide arms, wherein the plurality of guide arms are sequentially connected to form a square shape, and the guide arms are connected to adjacent positioning piles, and the plurality of guide arms are arranged around the periphery of the construction area; 4) Driving multiple Larsen steel sheet piles in sequence along the sides of the multiple guide arms. The multiple Larsen steel sheet piles are arranged around the periphery of the construction area to form four linear pile rows. The bottoms of the Larsen steel sheet piles extend into the solid soil layer, and adjacent Larsen steel sheet piles are sealed. 5) A transversely arranged perimeter purlin is provided on two oppositely arranged pile rows. The perimeter purlin is welded to a plurality of Larsen steel sheet piles of the pile row. A transversely arranged steel support is provided between the two perimeter purlins. The ends of the steel support are respectively connected to the perimeter purlins. The steel support and the two perimeter purlins form an internal support structure. 6) During the process of pumping water from the construction area and clearing silt from the construction area, the construction step 5) is repeated until the solid soil layer is exposed at the bottom of the construction area, and a plurality of internal support structures are formed in the construction area. The plurality of internal support structures are arranged in sequence along the height direction of the construction area, and the plurality of Larsen steel sheet piles and the plurality of internal support structures form a Larsen steel sheet pile cofferdam.

2. The Larsen steel sheet pile cofferdam construction method suitable for deep water areas according to claim 1, characterized in that: In the construction step 1), the construction platform is formed by splicing a plurality of pontoons floating on the water surface. The construction platform is provided with a plurality of insertion rods, which are inserted into the solid soil layer at the bottom of the deep water area to fix the construction platform on the water surface.

3. The Larsen steel sheet pile cofferdam construction method suitable for deep water areas according to claim 1, characterized in that: In the construction step 2), a pile driver is arranged on the construction platform. The pile driver is equipped with a vibrating hammer, and the vibrating hammer is used to drive positioning piles into the construction location.

4. The Larsen steel sheet pile cofferdam construction method suitable for deep water areas according to claim 1, characterized in that: In the construction step 2), a positioning corbel is provided on the positioning pile, and a positioning platform is provided on the top of the positioning corbel; in the construction step 3), the guide arm is placed on the positioning platform of the positioning corbel and fixedly connected to the positioning corbel by welding.

5. The Larsen steel sheet pile cofferdam construction method suitable for deep water areas according to any one of claims 1 to 4, characterized in that: In the construction step 4), both sides of the Larsen steel sheet piles have curved edges, and the curved edges enclose a curved groove. Between adjacent Larsen steel sheet piles, the curved edges are embedded in the curved groove, so that the adjacent Larsen steel sheet piles are connected as a whole, and the adjacent Larsen steel sheet piles are sealed.

6. The Larsen steel sheet pile cofferdam construction method suitable for deep water areas according to claim 5, characterized in that: In the construction step 4), the Larsen steel sheet pile includes a straight segment, and both sides of the straight segment have inclined segments, the inner ends of the inclined segments are butted against the ends of the straight segment, and the outer ends of the inclined segments form the curved edges; adjacent Larsen steel sheet piles are arranged in opposite staggered positions so that the curved edges are embedded in the curved grooves.

7. The Larsen steel sheet pile cofferdam construction method suitable for deep water areas according to any one of claims 1 to 4, characterized in that: In the construction step 4), a corner position is formed between adjacent rows of piles, and a corner steel sheet pile is provided at the corner position. The corner steel sheet pile is bent at a right angle, and both sides of the corner steel sheet pile have curved hook edges. The two sides of the corner steel sheet pile are respectively connected to the Larsen steel sheet piles of the adjacent pile row, and the hook edges are embedded in the curved groove, and the corner steel sheet pile and the Larsen steel sheet pile are sealed.

8. The Larsen steel sheet pile cofferdam construction method suitable for deep water areas according to any one of claims 1 to 4, characterized in that: In the construction step 5), the assembled Larsen steel sheet piles are provided with supporting corbels, the tops of the supporting corbels are provided with supporting platforms, the perimeter purlins are fixed on a plurality of supporting platforms, and are fixedly connected to a plurality of the Larsen steel sheet piles.

9. The Larsen steel sheet pile cofferdam construction method suitable for deep water areas according to claim 5, characterized in that: In the construction step 4), the end of the curved edge is recessed inward to form a recessed groove, and the recessed groove is filled with an elastic sealing strip. The sealing strip is movably arranged in the recessed groove and extends to the outside of the recessed groove to form an outer section. Side sections are formed on both sides of the outer section, and the two side sections are respectively clamped on both sides of the curved edge; The sealing strip, the outer section and the two side sections are integrally formed. When the curved edge is embedded in the curved groove, the outer section presses against the inner side wall of the curved groove to compress and deform the outer section and the sealing strip. The sealing strip is fixed in the recessed groove, and the two side sections are squeezed and clamped on both sides of the curved edge.

10. The Larsen steel sheet pile cofferdam construction method suitable for deep water areas according to claim 9, characterized in that: In the construction step 4), a deformation gap is provided between the sealing strip and the bottom of the recessed groove, the outer section protrudes outward to form a raised portion, and a hard guide strip is provided in the sealing strip. The guide strip is wrapped in the sealing strip and extends along the depth direction of the recessed groove. The guide strip passes through the outer section and extends into the raised portion. When the curved edge is embedded in the curved groove, the protrusion abuts against the inner wall of the curved groove, the outer section and the sealing strip are compressed and deformed, and the guide strip guides the sealing strip to compress and deform toward the deformation gap until the deformation gap is filled.

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