Construction method of water-rich stratum area foundation pit waterproof curtain

Abstract

The application relates to a construction method of a water-stop curtain of a foundation pit in a water-rich stratum area, which is applied in the field of foundation pit waterproofing. The method comprises the following steps: a steel sheet pile construction step, determining the positions of steel sheet pile hole positions and drilling holes to form the steel sheet pile hole positions, inserting the steel sheet piles into the hole positions and fixing the steel sheet piles, a rotary jetting pile construction step, drilling rotary jetting pile hole positions, high-pressure jet grouting by a jet pipe, and forming rotary jetting piles; a reinforcing mechanism construction step, excavating the soil layer in the gap after the rotary jetting piles are solidified to form an installation groove for installing a reinforcing member, fixing the reinforcing mechanism in the installation groove and abutting the reinforcing mechanism between the rotary jetting piles and the steel sheet piles, abutting one end of the reinforcing mechanism on a connecting mechanism, abutting the other end of the reinforcing mechanism on the outer wall of the rotary jetting pile, and backfilling the installation groove with earthwork. The application has the effects of reducing the possibility of sealing failure of the steel sheet pile, improving the sealing performance of the steel sheet pile, and utilizing the reinforcing mechanism to assist the steel sheet pile in supporting the side wall of the foundation pit, so that the steel sheet pile has stronger pressure-bearing capacity.

Description

Technical Field

[0001] This application relates to the field of foundation pit waterproofing, and in particular to the construction method of water-stop curtain for foundation pits in water-rich strata. Background Technology

[0002] A water-stopping curtain is a continuous water-stopping body used to prevent or reduce the inflow of groundwater into the foundation pit from the side walls and bottom of the foundation pit. It is generally composed of steel sheet piles and jet grouting piles to prevent the foundation pit from collapsing. In addition to supporting the foundation pit, the steel sheet piles can also assist the jet grouting piles in waterproofing.

[0003] A high-strength water-stop curtain structure for water-rich sandy strata is described in the related technology. The sheet piles are connected by connectors, and there are seals between adjacent sheet piles to seal the gaps between them, thus forming a sealing effect. When water comes in, it plays a certain role in stopping the water flow. It works in conjunction with jet grouting piles installed on the side of the sheet piles near the foundation pit to achieve a better water-stopping effect.

[0004] In water-rich areas, the soil layers are generally loose and irregular, making them prone to collapse. The pressure from the collapsed soil layer then acts entirely on the sheet piles. However, during actual installation, the seals between adjacent sheet piles are typically made of rubber, and the connectors used to link the sheet piles are usually movable for easy disassembly. Therefore, once the soil in the foundation pit collapses, the pressure is entirely borne by the sheet piles, seals, and connectors, leading to rapid seal failure and a swift weakening of the waterproofing effect. Summary of the Invention

[0005] To address the issue of low strength of sheet piles on the outer side of the cutoff wall, this application provides a construction method for a cutoff wall in a foundation pit in a water-rich stratum.

[0006] The construction method for a water-retaining curtain in a foundation pit in a water-rich stratum area provided in this application adopts the following technical solution:

[0007] A construction method for a water-rich stratum area foundation pit cutoff wall includes the following steps:

[0008] The construction steps for sheet piles are as follows: determine the location of sheet pile holes around the uncracked foundation pit and drill holes to form sheet pile holes. The depth of the sheet pile holes is greater than the depth of the uncracked foundation pit and extends below the groundwater level. The sheet piles are inserted into the holes and fixed. Sealing elements are placed between adjacent sheet piles to seal the gap between them. Adjacent sheet piles are connected by a connecting mechanism.

[0009] The construction steps of jet grouting piles are as follows: the jet grouting pile is located on the side of the steel sheet pile facing the foundation pit, and there is a gap between the jet grouting pile and the steel sheet pile. The drilling rig is used to drill the jet grouting pile hole. The depth of the jet grouting pile hole is greater than the depth of the steel sheet pile hole. High-pressure jet grouting is performed by passing a jet pipe through the jet grouting pile hole to form the jet grouting pile.

[0010] The construction steps for the reinforcement mechanism are as follows: After the jet grouting piles have solidified, the soil layer in the gaps is excavated to form an installation groove for installing the reinforcement. The installation groove is the same depth as the foundation pit. The outer walls of the jet grouting piles and the outer walls of the sheet piles serve as the side walls of the installation groove. The reinforcement mechanism is fixed in the installation groove and supported between the jet grouting piles and the sheet piles. One end of the reinforcement mechanism supports the connecting mechanism, and the other end of the reinforcement mechanism supports the outer wall of the jet grouting piles. Then, the installation groove is backfilled with soil, and the process is complete.

[0011] By adopting the above technical solution, when the water-rich stratum collapses, the pressure is first applied to the sheet piles, causing them to deform. At this time, the reinforcing mechanism comes into play, providing support for the sheet piles and reducing the possibility of deformation, thereby reducing the possibility of sealing failure and improving the sealing performance of the sheet piles. Furthermore, the reinforcing mechanism assists the sheet piles in supporting the sidewalls of the foundation pit, making the sheet piles more pressure-bearing.

[0012] Optionally, the reinforcing mechanism includes a driving component and a supporting component. The driving component is disposed on the supporting component. One end of the supporting component abuts against the sheet pile, and the other end of the supporting component abuts against the outer wall of the jet grouting pile. The driving component drives the two ends of the supporting component to move away from each other.

[0013] By adopting the above technical solution, the construction of the support components and drive components is carried out simultaneously during the construction of the water-stop curtain. After the construction is completed, the support components initially provide an initial support force for the jet grouting piles and sheet piles. When groundwater accidentally enters between the sheet piles and jet grouting piles, it can trigger the drive components to further support the sheet piles, resulting in smaller deformation of the sheet piles and the sealing components between the sheet piles, making the seal of the sheet piles more stable and less prone to damage.

[0014] Optionally, the supporting component includes a support frame, a supporting rod, and a check valve. The support frame has several insertion holes, and the supporting rod passes through the insertion holes. The supporting rod includes an outer sleeve rod and an inner sleeve rod. One end of the outer sleeve rod has a slot along its length, and one end of the inner sleeve rod is inserted into the slot and slides along the slot.

[0015] One end of the inner sleeve rod extends out of the outer sleeve rod and abuts against the sheet pile. The other end of the outer sleeve rod, away from the slot, abuts against the side wall of the jet grouting pile. The check valve is fixed to the end of the inner sleeve rod inserted into the slot and placed inside the slot. The drive assembly is fixed on the support frame and drives the outer sleeve rod and the inner sleeve rod to move away from each other.

[0016] By adopting the above technical solution, when the support rod abuts against the sheet pile and jet grouting pile, it tightens against the sheet pile. When the water-rich stratum collapses, the support rod can assist the sheet pile in achieving the supporting effect. At the same time, with the additional supporting force of the support rod, the deformation of the sheet pile is reduced, the deformation of the sealing parts between the sheet piles is reduced, and the sealing of the sheet pile is more stable and less prone to damage.

[0017] Optionally, the check valve includes a pawl hinged to the end of the inner sleeve rod, and a torsion spring is provided between the pawl and the inner sleeve rod;

[0018] The inner wall of the slot is provided with several slots along the length of the slot, and the slots are parallel to each other. The torsion spring pushes the claw to abut against the bottom wall of the slot.

[0019] By adopting the above technical solution, when water leakage occurs in the gaps between sheet piles, the bracing rods abut against the sheet piles, making the gaps between the sheet piles smaller. This increases the pressure resistance of the seals between the sheet piles, resulting in a better pressure seal. The torsion springs directly abut the claws against the inner wall of the slot. When the sheet pile is subjected to additional pressure, the outer and inner sleeve rods approach each other, and the claws abut against the side wall of the slot, creating a limiting effect and providing additional support to the sheet pile, thus strengthening its pressure-bearing capacity.

[0020] Optionally, the slot is provided with a slope, and the end of the slope near the inner sleeve rod is higher than the end of the slope away from the inner sleeve rod.

[0021] By adopting the above technical solution, the slope plays a guiding role. When the outer sleeve rod and the inner sleeve rod move away from each other, the pawl can be smoothly pulled out of the slot by the guiding effect of the slope.

[0022] Optionally, a rotating shaft is fixed on the inner sleeve rod, and a through hole is provided on the pawl. The pawl is sleeved on the rotating shaft through the through hole. A torsion spring is sleeved on the rotating shaft and placed between the inner wall of the through hole and the rotating shaft. One end of the torsion spring is fixed on the inner wall of the through hole, and the other end of the torsion spring is fixed on the rotating shaft.

[0023] By adopting the above technical solution, the torsion spring pushes the claw to abut against the side wall of the slot. When the outer sleeve rod and the inner sleeve rod move relative to each other, the claw can be pushed to engage in different slots, so that the inner sleeve rod and the outer sleeve rod will not retract after being supported, and the supporting effect is good.

[0024] Optionally, the check valve includes a limiting claw and a tension spring. The limiting claw is hinged to one end of the inner sleeve rod, one end of the tension spring is fixed to the limiting claw, and the other end of the tension spring is fixed to the inner sleeve rod. A plurality of limiting grooves are formed on the inner wall of the slot, and limiting members are provided in the limiting grooves. The tension spring drives the limiting claw to insert into the limiting member.

[0025] By adopting the above technical solution, a tension spring can also be used as the power source, which is convenient for replacement.

[0026] Optionally, the limiting member is disposed on the inner wall of the limiting groove, and the side wall of the limiting claw is provided with a plurality of snap-fit ​​grooves, the plurality of snap-fit ​​grooves being arranged in parallel, and the limiting member snapping into the limiting groove when the limiting claw is inserted into the limiting groove.

[0027] By adopting the above technical solution, when the inner sleeve rod shows a tendency to retract, the limiting component is pushed to lock the limiting claw. The greater the tendency to retract, the greater the locking force, which can effectively prevent the retraction phenomenon from occurring and make the support more stable.

[0028] Optionally, the limiting component includes a rotating shaft, a transmission shaft, a push plate, and a barb. The rotating shaft is fixed on the inner wall of the limiting groove, and a rotating hole is opened in the middle of the transmission shaft. The rotating shaft is inserted into the rotating hole and rotates around the rotating shaft.

[0029] The push plate is located at one end of the drive shaft near the bottom of the limiting groove. When the limiting claw is inserted into the limiting groove, it pushes the drive shaft to rotate by pushing against the push plate. The barb is located at one end of the drive shaft away from the bottom of the limiting groove. When the drive shaft rotates, the barb engages in the snap-fit ​​groove.

[0030] By adopting the above technical solution, after the inner sleeve rod is fixed, the limiting claw is inserted into the limiting groove, thereby driving the transmission shaft to rotate. At this time, the barb is pushed and engaged in the engagement groove to prevent the inner sleeve rod from retracting. The stronger the tendency to retract, the tighter the barb is engaged in the engagement groove, thereby improving the support strength.

[0031] Optionally, the drive assembly includes a cylinder, a first piston, and a second piston. The cylinder has a first opening and a second opening symmetrically formed. The first piston is inserted into the cylinder through the first opening, and the second piston is inserted into the cylinder through the second opening. The cylinder between the first piston and the second piston is filled with water-absorbing resin. The cylinder has several water-permeable holes.

[0032] The first piston is fixed with a first connecting rod on the side facing the first opening. The end of the first connecting rod extending out of the cylinder is connected to the adjacent inner sleeve rod. The second piston is fixed with a second connecting rod on the side facing the second opening. The end of the second connecting rod extending out of the cylinder is connected to the adjacent outer sleeve rod.

[0033] By adopting the above technical solution, when groundwater surges up and seeps into the cylinder through the permeable holes, the water-absorbing resin absorbs water and expands, further providing support. The supporting effect is better.

[0034] In summary, this application includes at least one of the following beneficial effects:

[0035] 1. When a water-rich stratum collapses, the pressure is first applied to the sheet piles, causing them to deform. At this time, the reinforcing mechanism comes into play, supporting the sheet piles and reducing the possibility of deformation, thereby reducing the possibility of sealing failure and improving the sealing performance of the sheet piles. Furthermore, the reinforcing mechanism assists the sheet piles in supporting the sidewalls of the pit, making the sheet piles more pressure-bearing.

[0036] 2. When the inner sleeve rod shows a tendency to retract, push the limiting component to lock the limiting claw. The greater the tendency to retract, the greater the locking force, which can effectively prevent the retraction phenomenon and make the support more stable. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the structure of the foundation pit water-stop curtain in an embodiment of this application;

[0038] Figure 2 This is a schematic diagram of the structure of a first embodiment of the reinforcing mechanism in the foundation pit water-stop curtain of this application;

[0039] Figure 3 This is a schematic cross-sectional view of the internal structure of the supporting component in Embodiment 1 of the reinforcement mechanism of this application;

[0040] Figure 4 for Figure 3 Enlarged structural diagram at point A in the middle;

[0041] Figure 5 This is a schematic diagram of the second embodiment of the reinforcing mechanism in the foundation pit water-stop curtain of this application;

[0042] Figure 6 This is a schematic cross-sectional view of the internal structure of the supporting component in Embodiment 2 of the reinforcement mechanism of this application;

[0043] Figure 7 for Figure 6 Enlarged structural diagram at point B;

[0044] Figure 8 This is a cross-sectional schematic diagram of the internal structure of the drive component of the reinforcement mechanism in an embodiment of this application;

[0045] In the diagram: 1. Sheet pile; 2. Jet grouting pile; 3. Reinforcing mechanism; 31. Support assembly; 311. Support frame; 312. Support rod; 3121. Outer sleeve rod; 3122. Inner sleeve rod; 3123. Slot; 313. Check valve; 3131. Claw; 3132. Torsion spring; 3133. Slot; 3134. Slope; 3135. Limiting claw; 3136. Tension spring; 3137. Drive shaft; 3138. Push plate; 3139. Barb; 32. Drive assembly; 321. Cylinder; 322. First piston; 323. Second piston; 324. Water permeable hole; 325. First connecting rod; 326. Second connecting rod. Detailed Implementation

[0046] The following is in conjunction with the appendix Figures 1-8 This application will be described in further detail.

[0047] This application discloses a construction method for a water-retaining curtain for a foundation pit in a water-rich stratum, comprising the following steps:

[0048] The construction steps for sheet pile 1 are as follows: The locations of the sheet pile 1 holes are determined around the perimeter of the uncracked foundation pit, and holes are drilled to form the sheet pile 1 holes. The depth of the sheet pile 1 holes is greater than the depth of the uncracked foundation pit and extends below the groundwater level. The sheet pile 1 is inserted into the holes and fixed in place. Adjacent sheet piles 1 are interlocked, and a sealing element is installed on the overlapping portion after interlocking. The sealing element is placed between adjacent sheet piles 1 to seal the gaps between them, forming a unified sheet pile 1 structure. The unified sheet pile 1 structure serves to support the soil layer outside the foundation pit. Simultaneously, when water seepage occurs in water-rich strata, the sealing element also provides a sealing function, so that the unified sheet pile 1 structure not only supports the sidewalls of the foundation pit but also acts as a water stopper. Common rubber sealing elements are sufficient; the only requirement is that they function as a water stopper.

[0049] The next step is to construct the jet grouting pile 2. The jet grouting pile 2 is located on the side of the sheet pile 1 facing the foundation pit, with a gap between them. A drilling rig is used to drill the holes for the jet grouting pile 2. The depth of the jet grouting pile 2 holes is greater than the depth of the sheet pile 1 holes. High-pressure jet grouting is then performed through the jet grouting pile 2 holes to form the jet grouting pile 2. After the jet grouting pile 2 is completed, it forms a continuous water-retaining wall, acting as a water barrier for the subsequently excavated foundation pit, and together with the sheet pile 1, forming a water-stop curtain for the foundation pit.

[0050] The water-rich strata have high water content, resulting in loose geology and a high probability of collapse. When the strata collapse, additional pressure is applied to the sheet piles 1, causing the seal between the sheet piles 1 to fail. Therefore, a reinforcing mechanism 3 can be installed between the jet grouting piles 2 and the sheet piles 1. The construction steps for the reinforcing mechanism 3 are as follows: After the jet grouting piles 2 are constructed, the soil layer in the gap between the jet grouting piles 2 and the sheet piles 1 is excavated to form an installation groove for the reinforcing component. The installation groove is the same depth as the foundation pit, with the outer walls of the jet grouting piles 2 and 1 serving as the side walls of the installation groove. The reinforcing mechanism 3 is fixed in the installation groove and supports the space between the jet grouting piles 2 and 1. One end of the reinforcing mechanism 3 supports the connecting mechanism, and the other end supports the outer wall of the jet grouting piles 2. The installation groove is then backfilled with soil. When a small amount of groundwater seeps in due to the collapse of the water-rich stratum, the seeping water triggers the reinforcing mechanism 3. The reinforcing mechanism 3 can support the sheet pile 1, reducing the possibility of deformation, thereby reducing the possibility of damage to the seals between the sheet piles 1, reducing the possibility of groundwater in the water-rich stratum flowing in through the sheet pile 1, improving the sealing performance of the sheet pile 1, and thus improving the sealing performance of the entire foundation pit water-stop curtain.

[0051] Reference Figure 1 and Figure 2The reinforcing mechanism 3 includes a drive assembly 32 and a supporting assembly 31. The drive assembly 32 is mounted on the supporting assembly 31. One end of the supporting assembly 31 abuts against the sheet pile 1, and the other end abuts against the outer wall of the jet grouting pile 2. The drive assembly 32 drives the two ends of the supporting assembly 31 away from each other. The supporting assembly 31 includes at least a support frame 311, a supporting rod 312, and a check valve 313. The drive assembly 32 is fixed to the support frame 311. The supporting rod 312 is also mounted on the support frame 311. Specifically, the support frame 311 has several insertion holes, and the supporting rod 312 passes through these holes. One end of the supporting rod 312 abuts against or is directly fixed to the sheet pile 1, especially at the gap between adjacent sheet piles 1, while the other end abuts against or is fixed to the outer wall of the jet grouting pile 2 to form a counter-supporting force. The support rod 312 includes an outer rod 3121 and an inner rod 3122. A slot 3123 is formed on the outer rod 3121, extending along its length. More preferably, the end face of the outer rod 3121 forms the opening of the slot 3123, and the central axis of the slot 3123 is the same as the central axis of the outer rod 3121. One end of the inner rod 3122 is inserted into the slot 3123 and slides along it. One support method involves the end of the inner rod 3122 extending from the outer rod 3121 abutting against the sheet pile 1, while the end of the outer rod 3121 facing away from the slot 3123 abuts against the side wall of the jet grouting pile 2. Of course, the same support function can be achieved by having the outer rod 3121 abut against the sheet pile 1 and the inner rod 3122 abut against the jet grouting pile 2. The check part 313 is fixed to one end of the inner sleeve rod 3122 that is inserted into the slot 3123 and is placed inside the slot 3123. When the drive assembly 32 drives the inner sleeve rod 3122 and the outer sleeve rod 3121 to move away from each other, the check part 313 will not interfere with the inner sleeve rod 3122 and the outer sleeve rod 3121 moving away from each other. When the inner sleeve rod 3122 and the outer sleeve rod 3121 approach each other, the check part 313 abuts against the slot 3123 to prevent the inner sleeve rod 3122 and the outer sleeve rod 3121 from retracting back.

[0052] Reference Figure 2 and Figure 3 One embodiment of the check valve 313 is as follows: the check valve 313 includes a pawl 3131, which is hinged to the end of the inner sleeve rod 3122, and a torsion spring 3132 is provided between the pawl 3131 and the inner sleeve rod 3122. Specifically, in conjunction with... Figure 4A rotating shaft is fixed on the inner sleeve rod 3122. A through hole is provided on the pawl 3131, which is sleeved onto the rotating shaft through the through hole. A torsion spring 3132 is sleeved on the rotating shaft, positioned between the inner wall of the through hole and the rotating shaft. One end of the torsion spring 3132 is fixed to the inner wall of the through hole, and the other end is fixed to the rotating shaft. The torque of the torsion spring 3132 can directly drive the pawl 3131 to abut against the inner wall of the slot 3123. Several slots 3133 are provided along the length of the slot 3123 on the inner wall of the slot 3123. These slots 3133 are parallel to each other. A slope 3134 can be provided within the slots 3133. The higher end of the slope 3134 is closer to the inner sleeve rod 3122, and the lower end is farther from the inner sleeve rod 3122. When… When the inner sleeve rod 3122 and the outer sleeve rod 3121 move away from each other to support the sheet pile 1 and the jet grouting pile 2, the slope surface 3134 acts as a guide. The claw 3131 moves from the low point of the slope surface 3134 to the high point of the slope surface 3134. That is, when the inner sleeve rod 3122 and the outer sleeve rod 3121 are driven away from each other by the drive assembly 32 to play a supporting role, the slope surface 3134 only plays a guiding role and will not interfere with the movement of the inner sleeve rod 3122 and the outer sleeve rod 3121 moving away from each other. When the inner sleeve rod 3122 and the outer sleeve rod 3121 approach each other, the claw 3131 moves from the high point of the slope 3134 to the low point of the slope 3134. At this time, the claw 3131 will press against the side wall of the groove 3133, which plays a limiting role and prevents the outer sleeve rod 3121 and the inner sleeve rod 3122 from approaching each other. This ensures that the supporting structure is more stable, the supporting effect is better, and the possibility of deformation is reduced. This reduces the possibility of damage to the seal between the sheet piles 1 and the possibility of groundwater in the water-rich strata flowing in through the sheet piles 1. This improves the sealing performance of the sheet piles 1 and thus improves the sealing performance of the entire foundation pit water-stop curtain.

[0053] Reference Figure 5 and Figure 6 Another embodiment of the check valve 313 is as follows: the check valve 313 includes a limiting claw 3135 and a tension spring 3136. Specifically, in conjunction with... Figure 7 The limiting claw 3135 is hinged to one end of the inner sleeve rod 3122. One end of the tension spring 3136 is fixed to the limiting claw 3135, and the other end of the tension spring 3136 is fixed to the inner sleeve rod 3122. Several limiting grooves are formed on the inner wall of the slot 3123, and limiting elements are provided in the limiting grooves. The tension spring 3136 drives the limiting claw 3135 to insert into the limiting elements. The limiting elements are provided on the inner wall of the limiting grooves, and several locking grooves are provided on the side wall of the limiting claw 3135. The locking grooves are arranged in parallel. When the limiting claw 3135 is inserted into the limiting groove, the limiting elements are engaged in the locking grooves.

[0054] Reference Figure 6 and Figure 7The limiting component includes a rotating shaft, a transmission shaft 3137, a push plate 3138, and a barb 3139. The rotating shaft is fixed to the inner wall of the limiting groove. A rotating hole is opened in the middle of the transmission shaft 3137, and the rotating shaft is inserted into the rotating hole and rotates around the rotating shaft. The push plate 3138 is located at one end of the transmission shaft 3137 near the bottom of the limiting groove. When the limiting claw 3135 is inserted into the limiting groove, it abuts against the push plate 3138. When the limiting claw 3135 is continuously inserted, it pushes the push plate 3138, causing the transmission shaft 3137 to rotate. The barb 3139 is fixed at one end of the transmission shaft 3137 away from the bottom of the limiting groove. When the transmission shaft 3137 rotates, the barb 3139 engages in the engaging groove. When the limiting claw 3135 shows a tendency to retract, it is pushed into the limiting groove. After entering the limiting groove, the limiting claw 3135 drives the drive shaft 3137 to rotate, thereby pushing the barb 3139 to abut against the limiting claw 3135. The greater the pushing force of the limiting claw, the greater the clamping force of the limiting claw 3135, which can reduce the possibility of the outer sleeve rod 3121 and the inner sleeve rod 3122 retracting during the supporting process, making the support more stable.

[0055] Reference Figure 1 and Figure 2 and Figure 5 When the sheet pile 1 is not permeable, the inner sleeve 3122 and the outer sleeve 3121 normally support the sheet pile 1 and the jet grouting pile 2, and the check part 313 prevents the outer sleeve 3121 and the inner sleeve 3122 from retracting. However, when the water-rich stratum collapses, the pressure of the surrounding soil acts on the sheet pile 1, causing the sheet pile 1 to deform. If the seal is damaged at this time, groundwater will seep into the space between the sheet pile 1 and the jet grouting pile 2. At this time, the drive assembly 32 can be triggered to apply additional pressure to the outer sleeve 3121 and the inner sleeve 3122. Preferably, refer to Figure 2 , Figure 5 and Figure 8The drive assembly 32 includes a cylinder 321, a first piston 322, and a second piston 323. A first opening and a second opening are symmetrically formed on the cylinder 321. The first piston 322 is inserted into the cylinder 321 through the first opening, and the second piston 323 is inserted into the cylinder 321 through the second opening. The space between the first piston 322 and the second piston 323 in the cylinder 321 is filled with absorbent resin. Several permeable holes 324 are formed on the cylinder 321. A first connecting rod 325 is fixed to the side of the first piston 322 facing the first opening. The end of the first connecting rod 325 extending out of the cylinder 321 is connected to an adjacent inner sleeve rod 3122. A second connecting rod 326 is fixed to the side of the second piston 323 facing the second opening. The end of the second connecting rod 326 extending out of the cylinder 321 is connected to an adjacent outer sleeve rod 3121. When groundwater seeps in, it enters the cylinder 321 through the permeable hole 324 and comes into contact with the water-absorbing resin. The water-absorbing resin absorbs water and expands, thereby pushing the outer sleeve rod 3121 and the inner sleeve rod 3122 away from each other. When only part of the cylinder 321 seeps in, it can also drive the adjacent inner sleeve rod 3122 and outer sleeve rod 3121 to move, thereby forming a good supporting effect around the seepage point of the sheet pile 1. This reduces the pressure on the sealing elements between the sheet piles 1, forming a stronger pressure sealing effect, reducing the possibility of groundwater in the water-rich strata flowing in through the sheet pile 1, improving the sealing performance of the sheet pile 1, and thus improving the sealing performance of the entire foundation pit water-stop curtain.

[0056] When the water-stop curtain in this embodiment is used, if the water-rich stratum collapses, the pressure is first applied to the sheet pile 1, causing the sheet pile 1 to deform. At this time, the reinforcing mechanism 3 comes into play, providing support for the sheet pile 1, reducing the possibility of deformation of the sheet pile 1, thereby reducing the possibility of sealing failure of the sheet pile 1, improving the sealing performance of the sheet pile 1, and using the reinforcing mechanism 3 to assist the sheet pile 1 in supporting the side wall of the foundation pit, making the sheet pile 1 more pressure-bearing.

[0057] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A construction method for a water-rich stratum area foundation pit cutoff wall, characterized in that: Includes the following steps: The construction steps of sheet pile (1) are as follows: the location of sheet pile (1) holes is determined around the unexcavated foundation pit and holes are drilled to form sheet pile (1) holes. The depth of the sheet pile (1) holes is greater than the depth of the unexcavated foundation pit and drills below the groundwater level. Sheet piles (1) are inserted into the holes and fixed. Sealing elements are placed between adjacent sheet piles (1) to seal the gap between adjacent sheet piles (1). Adjacent sheet piles (1) are connected by a connecting mechanism. The construction steps of jet grouting pile (2) are as follows: the jet grouting pile (2) is located on the side of the sheet pile (1) facing the foundation pit, and there is a gap between it and the sheet pile (1). The drilling machine is used to drill the hole position of the jet grouting pile (2). The depth of the hole position of the jet grouting pile (2) is greater than the depth of the hole position of the sheet pile (1). The jet grouting pipe is passed through the hole position of the jet grouting pile (2) for high-pressure jet grouting to form the jet grouting pile (2). The construction steps of the reinforcement mechanism (3) are as follows: After the jet grouting pile (2) solidifies, the soil layer in the gap is excavated to form an installation groove for installing the reinforcement. The installation groove is the same depth as the foundation pit. The outer wall of the jet grouting pile (2) and the outer wall of the sheet pile (1) are used as the side walls of the installation groove. The reinforcement mechanism (3) is fixed in the installation groove and supported between the jet grouting pile (2) and the sheet pile (1). One end of the reinforcement mechanism (3) is supported on the connecting mechanism, and the other end of the reinforcement mechanism (3) is supported on the outer wall of the jet grouting pile (2). Then the installation groove is backfilled with soil. The strengthening mechanism (3) includes a driving component (32) and a supporting component (31). The driving component (32) is disposed on the supporting component (31). One end of the supporting component (31) abuts against the sheet pile (1), and the other end of the supporting component (31) abuts against the outer wall of the jet grouting pile (2). The driving component (32) drives the two ends of the supporting component (31) to move away from each other. The supporting component (31) includes a support frame (311), a supporting rod (312), and a check part (313). The support frame (311) has several insertion holes. The supporting rod (312) passes through the insertion holes. The supporting rod (312) includes an outer rod (3121) and an inner rod (3122). One end of the outer rod (3121) has a slot (3123) along the length direction of the outer rod (3121). One end of the inner rod (3122) is inserted into the slot (3123) and slides along the slot (3123). The inner sleeve rod (3122) extends out of the outer sleeve rod (3121) and abuts against the sheet pile (1). The outer sleeve rod (3121) abuts against the side wall of the jet grouting pile (2) at the end away from the slot (3123). The check valve (313) is fixed to the end of the inner sleeve rod (3122) inserted into the slot (3123) and placed inside the slot (3123). The drive assembly (32) is fixed on the support frame (311) and drives the outer sleeve rod (3121) and the inner sleeve rod (3122) to move away from each other.

2. The construction method of a water-rich stratum area foundation pit water-stop curtain according to claim 1, characterized in that: The check valve (313) includes a pawl (3131), which is hinged to the end of the inner sleeve rod (3122), and a torsion spring (3132) is provided between the pawl (3131) and the inner sleeve rod (3122). The inner wall of the slot (3123) is provided with a plurality of slots (3133) along the length direction of the slot (3123). The plurality of slots (3133) are parallel to each other, and the torsion spring (3132) pushes the claw (3131) to abut against the bottom wall of the slot (3133).

3. The construction method of a water-rich stratum area foundation pit water-stop curtain according to claim 2, characterized in that: The slot (3133) is provided with a slope (3134), and the end of the slope (3134) near the inner sleeve rod (3122) is higher than the end of the slope (3134) away from the inner sleeve rod (3122).

4. The construction method of a water-rich stratum area foundation pit water-stop curtain according to claim 3, characterized in that: The inner sleeve rod (3122) is fixed with a rotating shaft. The pawl (3131) is provided with a through hole. The pawl (3131) is sleeved on the rotating shaft through the through hole. The torsion spring (3132) is sleeved on the rotating shaft and placed between the inner wall of the through hole and the rotating shaft. One end of the torsion spring (3132) is fixed on the inner wall of the through hole, and the other end of the torsion spring (3132) is fixed on the rotating shaft.

5. The construction method of a water-rich stratum area foundation pit water-stop curtain according to claim 1, characterized in that: The check valve (313) includes a limiting claw (3135) and a tension spring (3136). The limiting claw (3135) is hinged to one end of the inner sleeve rod (3122). One end of the tension spring (3136) is fixed to the limiting claw (3135), and the other end of the tension spring (3136) is fixed to the inner sleeve rod (3122). A plurality of limiting grooves are provided on the inner wall of the slot (3123). A limiting member is provided in the limiting groove. The tension spring (3136) drives the limiting claw (3135) to insert into the limiting member.

6. The construction method of a water-rich stratum foundation pit cutoff curtain according to claim 5, characterized in that: The limiting member is provided on the inner wall of the limiting groove, and the side wall of the limiting claw (3135) is provided with a plurality of snap-fit ​​grooves. The plurality of snap-fit ​​grooves are arranged in parallel. When the limiting claw (3135) is inserted into the limiting groove, the limiting member snaps into the limiting groove.

7. The construction method of a water-rich stratum area foundation pit water-stop curtain according to claim 6, characterized in that: The limiting component includes a rotating shaft, a transmission shaft (3137), a push plate (3138), and a barb (3139). The rotating shaft is fixed on the inner wall of the limiting groove. A rotating hole is opened in the middle of the transmission shaft (3137). The rotating shaft is inserted into the rotating hole and the transmission shaft (3137) rotates around the rotating shaft. The push plate (3138) is located at one end of the drive shaft (3137) near the bottom of the limiting groove. When the limiting claw (3135) is inserted into the limiting groove, it pushes the drive shaft (3137) to rotate by pushing against the push plate (3138). The barb (3139) is located at one end of the drive shaft (3137) away from the bottom of the limiting groove. When the drive shaft (3137) rotates, the barb (3139) engages in the snap-fit ​​groove.

8. The construction method of a water-rich stratum area foundation pit water-stop curtain according to claim 1, characterized in that: The drive assembly (32) includes a cylinder (321), a first piston (322), and a second piston (323). The cylinder (321) has a first opening and a second opening symmetrically arranged on it. The first piston (322) is inserted into the cylinder (321) through the first opening, and the second piston (323) is inserted into the cylinder (321) through the second opening. The cylinder (321) between the first piston (322) and the second piston (323) is filled with water-absorbing resin. The cylinder (321) has a plurality of water-permeable holes (324). The first piston (322) fixes the first connecting rod (325) to the side facing the first opening. The end of the first connecting rod (325) extending out of the cylinder (321) is connected to the adjacent inner sleeve rod (3122). The second piston (323) fixes the second connecting rod (326) to the side facing the second opening. The end of the second connecting rod (326) extending out of the cylinder (321) is connected to the adjacent outer sleeve rod (3121).

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