Double-row water stop steel sheet pile cofferdam supporting structure and construction method

Abstract

The invention provides a double-row water-stopping steel sheet pile cofferdam supporting structure and a construction method. The supporting structure comprises Larsen steel sheet piles, a plurality of water-stopping steel sheet piles and a plurality of water-stopping steel sheet piles, the T-shaped steel sheet pile comprises a common Larsen steel sheet pile and a partition plate buckle fixedly connected to a web plate of the common Larsen steel sheet pile, and the partition plate buckle is formed by cutting the web plate of another common Larsen steel sheet pile. Buckling parts on webs of the Larsen steel sheet piles and the T-shaped steel sheet piles are sequentially buckled to form single-layer steel sheet pile supporting layers, the two groups of steel sheet pile supporting layers are arranged in parallel, a supporting gap is formed between the two groups of steel sheet pile supporting layers, and a plurality of partition plate buckles on the two groups of steel sheet pile supporting layers are buckled and connected in a one-to-one correspondence manner; the two buckled partition plate buckles divide the supporting gap into a plurality of compartments, and the compartments are filled with filler layers. The T-shaped steel sheet piles are manufactured by using the common Larsen steel sheet piles of the same specification, and rigid connection is performed by virtue of the partition plate buckles, so that the construction efficiency is improved, and the water stop performance is ensured.

Description

Technical Field

[0001] The present application relates to the technical field of cofferdam support structures, and in particular to a double-row water-stop steel sheet pile cofferdam support structure and a construction method. Background Art

[0002] With the development of cities, municipal infrastructure is constantly improving, and small transportation buildings such as municipal bridges are increasing. In order to build bridge piers, it is necessary to build cofferdams as temporary enclosure structures. Its function is to prevent water and soil from entering the construction site of the building, so as to drain water, excavate foundation pits, and build buildings.

[0003] Larsen steel sheet piles have the advantages of high quality, high strength, light texture, convenient construction, green economy and reusability. They are used in foundation pit support methods to maintain the stability of foundation pits. However, after being hammered into the soil, Larsen steel sheet piles may cause gaps in the joint locks, leaking water and sand, causing the internal filler of the double-row steel sheet piles to be lost, and the inner row of steel sheet piles to be unstable and unevenly settled. If they are not discovered and handled in time, it will not only delay the construction period but also easily cause safety accidents, resulting in casualties and property losses. Therefore, it is necessary to analyze the causes of leakage at the steel sheet pile joints and study the methods of plugging the leakage. Summary of the invention

[0004] In order to improve the problems of low construction efficiency and easy leakage of traditional double-row steel sheet pile tie rod structures, the present application provides a double-row water-stop steel sheet pile cofferdam support structure and a construction method.

[0005] In the first aspect, the present application provides a double-row water-stop steel sheet pile cofferdam support structure, which adopts the following technical solution: A double-row water-stop steel sheet pile cofferdam support structure, comprising: Larsen Steel Sheet Piles; The T-shaped steel sheet pile comprises an ordinary Larsen steel sheet pile and a partition buckle fixed to the web of the ordinary Larsen steel sheet pile, wherein the partition buckle is made by cutting another ordinary Larsen steel sheet pile from the web; The buckling parts on the webs of the Larsen steel sheet piles and the T-shaped steel sheet piles are buckled in sequence to form a single-layer steel sheet pile support layer, the two groups of steel sheet pile support layers are arranged in parallel with a support gap between them, and the multiple partition buckles on the two groups of steel sheet pile support layers are buckled and connected one by one; The two interlocking partition buckles divide the support gap into a plurality of compartments, and the compartments are filled with a filler layer.

[0006] Furthermore, at least one Larsen steel sheet pile is arranged between two adjacent T-shaped steel sheet piles in the single-layer steel sheet pile supporting layer.

[0007] Furthermore, reinforcing ribs are welded and fixed between the partition buckles in the T-shaped steel sheet piles and the webs of ordinary Larsen steel sheet piles.

[0008] Furthermore, the interval between two adjacent reinforcing ribs in the T-shaped steel sheet pile is not greater than 1500 mm, and the thickness of the reinforcing rib is not less than 10 mm.

[0009] Furthermore, the filler layer is one or a mixture of gravel, crushed stone, and soil.

[0010] Furthermore, a geotextile layer is provided between the filler layer and the steel sheet pile supporting layer.

[0011] Furthermore, the joints in the steel sheet pile supporting layer are filled with a polyurethane waterproof adhesive layer.

[0012] In a second aspect, the present application provides a double-row water-stop steel sheet pile cofferdam support construction method, based on the above-mentioned double-row water-stop steel sheet pile cofferdam support structure, comprising the following steps: S1. Determine the specifications and models of steel sheet piles according to the construction drawings and plan requirements, and calculate the amount of steel sheet piles used; S2. The ordinary Larsen steel sheet pile is cut from the web to obtain two of the partition buckles, and then the partition buckles are welded and fixed to the web of another ordinary Larsen steel sheet pile to obtain the T-shaped steel sheet pile; S3. When driving the steel sheet piles, first drive the outer steel sheet pile support layer, drive the Larsen steel sheet piles and the T-shaped steel sheet piles into place at intervals, and set the partition buckles on the T-shaped steel sheet piles inward; S4. After the outer steel sheet pile support layer is injected and closed, the inner steel sheet pile support layer can be injected, and the partition buckles on the T-shaped steel sheet piles in the steel sheet pile support layer are outwardly locked with the partition buckles on the T-shaped steel sheet piles to form a complete partition structure; S5. Dewatering the support gap between the inner and outer steel sheet pile support layers. After dewatering, roll the geotextile in the support gap, leaving an appropriate deformation margin, and then fill the filler layer; S6. After the inner and outer steel sheet pile support layers are basically formed and monitored to be stable, apply polyurethane waterproof adhesive to the joints in the inner steel sheet pile support layer to complete the construction of the double-row steel sheet pile waterproof cofferdam.

[0013] Furthermore, after step S4 is completed, the surrounding purlins and internal supports of the support structure are first constructed according to the water level depth in the internal construction area of ​​the inner steel sheet pile support layer, and drainage is carried out at the same time, following the principle of "support first, then drainage" to prevent the support structure from becoming unstable due to the internal and external pressure difference.

[0014] Furthermore, after the drainage of the internal construction area of ​​the inner steel sheet pile support layer is completed, the bottom is sealed in time to prevent leakage and pipe bursts at the bottom.

[0015] In summary, the present application includes at least one of the following beneficial technical effects: 1. By using ordinary Larsen steel sheet piles of the same specifications as Larsen steel sheet piles to make T-shaped steel sheet piles, there is no need to purchase profiles for installation, which can significantly reduce construction costs; during construction, ordinary Larsen steel sheet piles are used for hammering, and construction can be done by hammering with a crawler excavator with a common vibrating hammer; the connection and transmission of force can be completed while the inner and outer single-layer steel sheet pile support layers are completed, which can effectively improve the complex operation of the traditional double-row steel sheet piles, which requires the pull rods to drill holes in the steel sheet piles and use manual special installation; 2. The inner and outer double-row single-layer steel sheet pile support layers are rigidly connected by two partition buckles in two opposing T-shaped steel sheet piles, so that the two rows of single-layer steel sheet pile support layers can be connected as a whole, thereby improving the strength of the cross-sectional rigidity of the entire steel sheet pile support structure and greatly improving the strength of the formed double-row steel sheet pile support structure with fixed pile heads; 3. The support gap between the inner and outer double-row single-layer steel sheet pile support layers is separated by the partition buckle in the T-shaped steel sheet pile, which can effectively detect and repair the leakage point when the river water leaks, avoiding the problem that too much water is stored between the inner and outer double-row single-layer steel sheet pile support layers and the leakage point cannot be found due to untimely discovery of river water leakage; 4. By using gravel, soil and other fillers to fill multiple compartments in the support gap to form a filler layer, on the one hand, it can effectively prevent river water from leaking into the construction area between the inner single-layer steel sheet pile support layer, and on the other hand, it can increase the deadweight of the double-row steel sheet pile support structure, improve stability and containment effect; and through the special compartment design, the detection and repair efficiency of the outer layer leakage points is improved, and the loss of the filler layer is reduced, which works together with the polyurethane water-stop adhesive to greatly improve the water-stop performance of the cofferdam. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 is a top view of the support structure of an embodiment of the present application; Figure 2 It is a schematic diagram of the structure of a T-shaped steel sheet pile according to an embodiment of the present application; Figure 3It is a processing schematic diagram of a T-shaped steel sheet pile according to an embodiment of the present application; Figure 4 It is a schematic diagram of processing the reinforcing ribs on the T-shaped steel sheet piles in the embodiment of the present application; Figure 5 It is a construction diagram of a single-layer steel sheet pile support layer in the construction method of the embodiment of the present application; Figure 6 It is a construction diagram of double-row steel sheet piles in the construction method of the embodiment of the present application.

[0018] Reference numerals: 1. Larsen steel sheet pile; 2. T-type steel sheet pile; 21. Partition buckle; 22. Reinforcement rib plate; 3. Steel sheet pile support layer; 4. Support gap; 41. Compartment; 5. Filling layer; 6. Polyurethane waterproof adhesive layer. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] Reference Figure 1 and Figure 2 The present application embodiment discloses a double-row water-stop steel sheet pile cofferdam support structure, which includes: The Larsen steel sheet pile 1 has a main body which is an ordinary Larsen steel sheet pile, specifically comprising a web and buckling parts arranged on both sides of the web.

[0021] The T-shaped steel sheet pile 2 includes an ordinary Larsen steel sheet pile and a partition buckle 21 fixed to the web of the ordinary Larsen steel sheet pile, wherein the partition buckle 21 is made by cutting another ordinary Larsen steel sheet pile from the web; in the specific production, the partition buckle 21 can be divided along the central part of the web of the ordinary Larsen steel sheet pile so that all T-shaped steel sheet piles 2 are consistent in size for easy assembly, and the other partition buckle 21 after cutting can be welded to another ordinary Larsen steel sheet pile without wasting materials; or, it can also be a non-center division, such as a 4:6 division, a 3:7 division, etc., thereby controlling the gap between the inner and outer layers of the double-row water-stop steel sheet piles, and attention should be paid to controlling the gap between the inner and outer layers during assembly.

[0022] The buckling parts on the webs of the Larsen steel sheet piles 1 and the T-shaped steel sheet piles 2 are buckled in sequence to form a single-layer steel sheet pile support layer 3. The two groups of steel sheet pile support layers 3 are arranged in parallel with a support gap 4 therebetween. The multiple partition buckles 21 on the two groups of steel sheet pile support layers 3 are arranged relatively and buckled in one by one.

[0023] The two interlocking partition buckles 21 separate the support gap 4 into multiple compartments 41. The compartments 41 are filled with a filler layer 5. The filler layer 5 is one or a mixture of gravel, crushed stone, and soil, which can be selected according to actual engineering needs.

[0024] Furthermore, at least one Larsen steel sheet pile 1 is arranged between two adjacent T-shaped steel sheet piles 2 in the steel sheet pile supporting layer 3, so that the size of the compartment 41 can be changed by adjusting the number of Larsen steel sheet piles 1 between two adjacent T-shaped steel sheet piles 2, thereby facilitating diversified arrangement of the steel sheet pile supporting layer 3.

[0025] In this way, by using ordinary Larsen steel sheet piles of the same specifications as the Larsen steel sheet piles 1 to make T-shaped steel sheet piles 2, there is no need to purchase profiles for installation, which can significantly reduce construction costs; during construction, ordinary Larsen steel sheet piles are used for hammering, and construction can be done by hammering with a crawler excavator with a common vibrating hammer. When the inner and outer steel sheet pile support layers 3 are completed, the force connection and transmission can be completed, which can effectively improve the traditional double-row steel sheet piles. The tie rods need to open holes in the steel sheet piles and use manual labor for special installation. Complex operations.

[0026] Furthermore, by rigidly connecting the inner and outer double-row steel sheet pile support layers 3 through the two partition buckles 21 in the two opposing T-shaped steel sheet piles 2, the two rows of steel sheet pile support layers 3 can be connected into a whole, thereby improving the strength of the cross-sectional stiffness of the entire steel sheet pile support structure and greatly improving the strength of the formed double-row steel sheet pile support structure with fixed pile heads.

[0027] In addition, the support gap 4 between the inner and outer double-row steel sheet pile support layers 3 is separated by the partition buckle 21 in the T-shaped steel sheet pile 2, and the leakage point can be effectively detected and repaired when the river water leaks, avoiding the problem that the leakage point cannot be found due to excessive water accumulation between the inner and outer double-row steel sheet pile support layers 3 due to untimely discovery of river water leakage. Moreover, the use of fillers such as gravel and soil to fill the multiple compartments 41 in the support gap 4 to form a filler layer 5 can effectively prevent river water from leaking into the construction area between the inner steel sheet pile support layers 3 on the one hand, and on the other hand, it can increase the self-weight of the double-row steel sheet pile support structure, improve stability and enclosure effect. And because of this partition structure, it can effectively prevent the loss of the filler layer 5 in the compartment 41 when the river water leaks.

[0028] In order to improve the structural strength of the welded T-shaped steel sheet pile 2, refer to Figure 3 and Figure 4 A reinforcing rib 22 is welded and fixed between the partition buckle 21 in the T-shaped steel sheet pile 2 and the web of the ordinary Larsen steel sheet pile. The interval between two adjacent reinforcing ribs 22 in the T-shaped steel sheet pile 2 is not more than 1500mm, and the thickness of the reinforcing rib 22 is not less than 10mm, so as to improve the stress structure of the support system and make the stress of the double-row steel sheet pile support structure more stable. In a specific example, a reinforcing rib 22 can be set every 1000mm, the thickness of the reinforcing rib 22 is 12mm, and the size of the fillet weld is 6mm.

[0029] In addition, a geotextile layer is provided between the packing layer 5 and the steel sheet pile support layer 3 to wrap the packing layer 5 and reduce the probability of the packing layer 5 being lost after water seepage. And because river water often leaks through the deformation of the steel sheet pile lock buckle, after the steel sheet pile is injected, polyurethane waterproof glue can be applied to the joints of the inner steel sheet pile support layer 3 to form a polyurethane waterproof glue layer 6; or, if river water leaks to the inner steel sheet pile support layer 3, polyurethane waterproof glue can be applied to expand in water and fill the deformation area of ​​the lock buckle, thereby achieving a strong waterproof effect.

[0030] The present application also discloses a double-row water-stop steel sheet pile cofferdam support construction method. Based on the above double-row water-stop steel sheet pile cofferdam support structure, the following technical solution is adopted: A double-row water-stop steel sheet pile cofferdam support construction method comprises the following steps: S1. Determine the specifications and models of steel sheet piles according to the construction drawings and plan requirements, and calculate the amount of steel sheet piles used.

[0031] S2. Cut the ordinary Larsen steel sheet pile from the web to obtain two partition buckles 21, and then weld the partition buckle 21 to the web of another ordinary Larsen steel sheet pile to obtain a T-shaped steel sheet pile 2. In a specific example, the ordinary Larsen steel sheet pile is pressed Figure 3 -A is cut along the aa section line to obtain the partition buckle 21, and then press Figure 3 -B for welding; or, further, the reinforcing ribs 22 may be welded at regular intervals between the bulkhead buckle 21 and the web, such as Figure 4 .

[0032] S3. When driving steel sheet piles, Figure 5 As shown, the outer steel sheet pile support layer 3 is first applied, and the Larsen steel sheet piles 1 and the T-shaped steel sheet piles 2 are driven in at intervals, and the partition buckles 21 on the T-shaped steel sheet piles 2 are set inward; and during the specific application, one Larsen steel sheet pile 1 can be set between two adjacent T-shaped steel sheet piles 2, or multiple Larsen steel sheet piles 1 can be set.

[0033] S4. After the outer steel sheet pile support layer 3 is injected and closed, the inner steel sheet pile support layer 3 can be injected. The partition buckles 21 on the T-shaped steel sheet piles 2 in the steel sheet pile support layer 3 face outward and interlock with the partition buckles 21 on the T-shaped steel sheet piles 2 to form a complete partition structure, such as Figure 6 shown.

[0034] S5. Dewater the support gap 4 between the inner and outer steel sheet pile support layers 3. After dewatering, roll the geotextile in the support gap 4, leaving appropriate deformation margin, and then fill it with gravel, crushed stone, soil and other fillers to form a filler layer 5; and when filling the filler, a 10CM thick sand cushion layer can be laid at the bottom first to prevent damage to the geotextile when backfilling the filler.

[0035] S6. After the inner and outer steel sheet pile supporting layers 3 are basically formed and monitored to be stable, polyurethane waterproof adhesive is applied to the joints in the inner steel sheet pile supporting layer 3 to form a polyurethane waterproof adhesive layer 6, and the construction of the double-row steel sheet pile waterproof cofferdam can be completed.

[0036] Among them, after the completion of step S4, the surrounding purlins and internal supports of the support structure are first constructed according to the water level depth of the internal construction area of ​​the inner steel sheet pile support layer 3, and drainage is carried out at the same time, following the principle of "support first, then drainage" to prevent the instability of the support structure caused by the internal and external pressure difference. In addition, after the drainage of the internal construction area of ​​the inner steel sheet pile support layer 3 is completed, the bottom is sealed in time to prevent leakage and pipe bursts at the bottom.

[0037] Therefore, the construction method of the present application can effectively solve the problem of water leakage caused by deformation of the lock buckle when using steel sheet pile support in the water area, which affects the construction progress. The use of the partition buckle 21 between the T-shaped steel sheet piles 2 improves the force between the inner and outer layers of the double-row steel sheet piles and reduces the installation steps of the traditional connection structure. In addition, the special compartment 41 design improves the detection and repair efficiency of the outer layer leakage point and reduces the loss of the packing layer 5. It works together with the polyurethane waterproof adhesive layer 6 to greatly improve the water-stopping performance of the cofferdam.

[0038] The implementation principle of a double-row water-stop steel sheet pile cofferdam support structure in the embodiment of the present application is: By using ordinary Larsen steel sheet piles of the same specifications as the Larsen steel sheet piles 1 to make T-shaped steel sheet piles 2, there is no need to purchase profiles for installation, which can significantly reduce construction costs; during construction, ordinary Larsen steel sheet piles are used for the injection process, and the construction can be completed by hammering with a crawler excavator with a common vibrating hammer. When the inner and outer steel sheet pile support layers 3 are injected, the force connection and transmission can be completed at the same time, which can effectively improve the traditional double-row steel sheet piles. The tie rods need to open holes in the steel sheet piles and use manual labor for special installation. Complex operations.

[0039] Furthermore, by rigidly connecting the inner and outer double-row steel sheet pile support layers 3 through the two partition buckles 21 in the two opposing T-shaped steel sheet piles 2, the two rows of steel sheet pile support layers 3 can be connected into a whole, thereby improving the strength of the cross-sectional stiffness of the entire steel sheet pile support structure and greatly improving the strength of the formed double-row steel sheet pile support structure with fixed pile heads.

[0040] In addition, the support gap 4 between the inner and outer double-row steel sheet pile support layers 3 is separated by the partition buckle 21 in the T-shaped steel sheet pile 2, so that the leakage point can be effectively detected and repaired when the river water leaks, avoiding the problem that the leakage point cannot be found due to excessive water accumulation between the inner and outer double-row steel sheet pile support layers 3 due to untimely detection of river water leakage. Moreover, the use of fillers such as gravel and soil to fill the multiple compartments 41 in the support gap 4 to form a filler layer 5 can, on the one hand, effectively prevent river water from leaking into the construction area between the inner steel sheet pile support layers 3, and on the other hand, increase the self-weight of the double-row steel sheet pile support structure, improve stability and enclosure effect. Moreover, the special design of the compartment 41 improves the detection and repair efficiency of the outer layer leakage point and reduces the loss of the filler layer 5. Together with the polyurethane waterproof adhesive layer 6, the water-stopping performance of the cofferdam is greatly improved.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A double-row water-stop steel sheet pile cofferdam support structure, characterized in that: include: Larsen Steel Sheet Piles; The T-shaped steel sheet pile comprises an ordinary Larsen steel sheet pile and a partition buckle fixed to the web of the ordinary Larsen steel sheet pile, wherein the partition buckle is made by cutting another ordinary Larsen steel sheet pile from the web; The buckling parts on the webs of the Larsen steel sheet piles and the T-shaped steel sheet piles are buckled in sequence to form a single-layer steel sheet pile support layer, the two groups of steel sheet pile support layers are arranged in parallel with a support gap between them, and the multiple partition buckles on the two groups of steel sheet pile support layers are buckled and connected one by one; The two interlocking partition buckles divide the support gap into a plurality of compartments, and the compartments are filled with a filler layer.

2. The double-row water-stop steel sheet pile cofferdam support structure according to claim 1 is characterized in that: At least one Larsen steel sheet pile is arranged between two adjacent T-shaped steel sheet piles in the single-layer steel sheet pile supporting layer.

3. The double-row water-stop steel sheet pile cofferdam support structure according to claim 1 is characterized in that: A reinforcing rib is welded and fixed between the partition buckle in the T-shaped steel sheet pile and the web of the ordinary Larsen steel sheet pile.

4. The double-row water-stop steel sheet pile cofferdam support structure according to claim 3 is characterized in that: The interval between two adjacent reinforcing ribs in the T-shaped steel sheet pile is no more than 1500 mm, and the thickness of the reinforcing rib is no less than 10 mm.

5. The double-row water-stop steel sheet pile cofferdam support structure according to claim 1 is characterized in that: The filler layer is one or a mixture of gravel, crushed stone and plain soil.

6. The double-row water-stop steel sheet pile cofferdam support structure according to claim 1 is characterized in that: A geotextile layer is arranged between the filler layer and the steel sheet pile supporting layer.

7. The double-row water-stop steel sheet pile cofferdam support structure according to claim 1 is characterized in that: The joints in the steel sheet pile supporting layer are filled with a polyurethane waterproof adhesive layer.

8. A double-row water-stop steel sheet pile cofferdam support construction method, based on a double-row water-stop steel sheet pile cofferdam support structure as claimed in any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Determine the specifications and models of steel sheet piles according to the construction drawings and plan requirements, and calculate the amount of steel sheet piles used; S2. The ordinary Larsen steel sheet pile is cut from the web to obtain two of the partition buckles, and then the partition buckles are welded and fixed to the web of another ordinary Larsen steel sheet pile to obtain the T-shaped steel sheet pile; S3. When driving the steel sheet piles, first drive the outer steel sheet pile support layer, drive the Larsen steel sheet piles and the T-shaped steel sheet piles into place at intervals, and set the partition buckles on the T-shaped steel sheet piles inward; S4. After the outer steel sheet pile support layer is injected and closed, the inner steel sheet pile support layer can be injected, and the partition buckles on the T-shaped steel sheet piles in the steel sheet pile support layer are outwardly locked with the partition buckles on the T-shaped steel sheet piles to form a complete partition structure; S5. Dewatering the support gap between the inner and outer steel sheet pile support layers. After dewatering, roll the geotextile in the support gap, leaving an appropriate deformation margin, and then fill the filler layer; S6. After the inner and outer steel sheet pile support layers are basically formed and monitored to be stable, apply polyurethane waterproof adhesive to the joints in the inner steel sheet pile support layer to complete the construction of the double-row steel sheet pile waterproof cofferdam.

9. The double-row water-stop steel sheet pile cofferdam support construction method according to claim 8 is characterized in that: After step S4 is completed, the surrounding purlins and inner supports of the support structure are first constructed according to the water level depth of the inner construction area of ​​the steel sheet pile support layer, and drainage is carried out at the same time, following the principle of "support first, then drainage" to prevent the support structure from becoming unstable due to the internal and external pressure difference.

10. The double-row water-stop steel sheet pile cofferdam support construction method according to claim 9, characterized in that: After the drainage of the internal construction area of ​​the inner steel sheet pile support layer is completed, the bottom is sealed in time to prevent leakage and pipe bursts at the bottom.

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