A rigid foundation pit support system and a construction method thereof

Abstract

The rigid foundation pit supporting system and the construction method thereof are provided for the problem that the water stop curtain of the existing foundation pit supporting system occupies the construction space and the bored pile is damaged. The system comprises a bored pile, a water stop structure arranged between two adjacent bored piles and engaged with the bored piles, a plurality of surrounding purlin supporting devices arranged at the pit-facing side of the water stop structure at intervals, a connecting rod of the surrounding purlin supporting device vertically fixed at one end of the water stop steel pipe and movably connected at the other end with a supporting plate, a telescopic rod of the diagonal brace hingedly connected with a bearing seat and abutting at the other end with the bottom of the supporting plate, and a construction method that the water stop structure provided with the surrounding purlin supporting devices is pressed into the foundation pit, the water stop steel plates on both sides of the water stop steel pipe are respectively inserted into the sockets of the two adjacent bored piles, and after the soil body of the foundation pit is excavated to a corresponding depth, the top ring beam or the surrounding purlin is supported on the surrounding purlin supporting devices located at the same horizontal plane, and the top ring beam, the surrounding purlin and the horizontal support are constructed layer by layer from top to bottom.

Description

Technical Field

[0001] This invention relates to the field of geotechnical engineering foundation pit support technology, and in particular to a rigid foundation pit support system and its construction method. Background Technology

[0002] In recent years, with the acceleration of urbanization and the increasing development and utilization of underground space, the depth of foundation pits has become deeper and deeper, and the construction requirements for foundation pit support structures have become higher and higher. They must not only meet the safety requirements during the deep foundation pit excavation process, but also have a certain degree of economic efficiency.

[0003] Currently, commonly used deep foundation pit support structures include sheet piles, construction piles, bored piles, and diaphragm walls. Among these, the foundation pit support system using "discrete bored piles + reinforced concrete / steel supports" has the following shortcomings:

[0004] 1. Since discrete cast-in-place piles do not have a water-stopping function, a separate water-stopping curtain (such as a triaxial mixing pile) is required to ensure the water-stopping effect during the deep foundation pit excavation process. The water-stopping curtain not only occupies a certain amount of construction space, but also affects the construction progress and increases the project cost.

[0005] 2. For reinforced concrete / steel supports, a top ring beam and walers are required between the bored pile and the support structure. During the construction of the top ring beam, the overlapping portion of the bored pile and the top ring beam is roughened to expose the main reinforcement. The top ring beam is then erected on top of the bored pile and integrated with its concrete pouring. During the construction of the walers, the concrete at the corresponding location of the bored pile is removed until the main reinforcement or embedded steel plate is exposed. Tie bars or steel brackets are welded to the main reinforcement or embedded steel plate of the bored pile, and the walers are then connected to one side of the bored pile using tie bars or waler supports. This construction method not only compromises the integrity of the bored pile but also makes the exposed main reinforcement or embedded steel plate susceptible to corrosion, reducing the strength of the bored pile. Therefore, how to study an economical and reasonable foundation pit support system and its construction method that can reduce the footprint of the water-stopping structure, achieve a good water-stopping effect, and not damage the bored piles is a technical problem that engineers in this field urgently need to solve. Summary of the Invention

[0006] The existing foundation pit support system, consisting of discrete bored piles and reinforced concrete / steel supports, suffers from several drawbacks. Firstly, the additional water-stop curtain occupies construction space, hindering construction progress. Secondly, the connection points between the bored piles and the top ring beam and walers are damaged, reducing the strength of the bored piles. The purpose of this invention is to provide a rigid foundation pit support system and its construction method.

[0007] The technical solution adopted by this invention to solve its technical problem is: a rigid foundation pit support system, comprising: bored cast-in-place piles, a water-stop structure, and a waler support device. The water-stop structure includes a water-stop steel pipe and water-stop steel plates vertically arranged on both sides of the water-stop steel pipe. The water-stop structure is arranged between two adjacent bored cast-in-place piles. The water-stop steel plates on both sides of the water-stop steel pipe are respectively engaged with the bored cast-in-place piles located on both sides. The tops of the bored cast-in-place piles and the water-stop structure are flush with the outdoor ground level. The side of each water-stop steel pipe near the foundation pit is vertically aligned along its axial direction. Multiple waler support devices are installed at intervals. The number and position of the waler support devices correspond to the actual number and position of the top ring beam and walers in the foundation pit. Each waler support device includes a connecting rod, a diagonal brace, and a support plate. The connecting rod and diagonal brace are installed vertically and at intervals along the axis of the waterstop steel pipe. One end of the connecting rod is vertically fixed to the waterstop steel pipe, and the other end is movably connected to the support plate. The diagonal brace includes a bearing seat and a telescopic rod hinged to it. The other end of the telescopic rod abuts against the bottom of the support plate. The waler support device is used to support the top ring beam and walers in the foundation pit.

[0008] The rigid foundation pit support system of the present invention includes bored piles, a water-stop structure vertically arranged and interlocking with two adjacent bored piles, and a plurality of waler support devices vertically and spaced apart on the pit-facing side of the water-stop structure. Each waler support device includes connecting rods and diagonal braces vertically and spaced apart along the axis of the water-stop steel pipe, and support plates respectively connected to both. One end of the connecting rod is vertically fixed to the water-stop steel pipe, and the other end is movably connected to the support plate. The diagonal brace includes a bearing seat and a telescopic rod hinged thereto, with the other end of the telescopic rod abutting against the bottom of the support plate. This rigid foundation pit support system has at least the following beneficial effects:

[0009] 1. A water-stopping structure with waler support device is inserted between discrete bored piles to form a foundation pit support system that integrates water-stopping and waler support. For discrete foundation pit support structures with water interception requirements, there is no need to set up a separate water-stopping curtain, avoiding the water-stopping curtain from occupying underground construction space. This not only ensures the water-stopping effect of the foundation pit support system, but also effectively reduces project costs and shortens the construction period, which is beneficial to the construction of foundation pit support structures in confined land space.

[0010] Second, multiple waler support devices are vertically installed on the side of the water-stop steel pipe of the water-stop structure. The number and position of the waler support devices are determined according to the actual number and position of the top ring beam and walers in the foundation pit. This ensures that the top ring beam and multiple walers in the foundation pit can be stably supported by the waler support devices on one side of the water-stop structure. There is no need to remove the concrete on the top and side of the bored pile, and there is no need to install hangers, corbels, or other structures to weld to the bored pile. This not only ensures the integrity of the bored pile structure, but also realizes the prefabricated construction of the foundation pit support system, improves construction efficiency, shortens the construction cycle, and has good economy and safety.

[0011] Third, the connecting rods, telescopic rods, and support plates of the waler support device are all movable connections, and the telescopic rods and water-stop steel pipes are hinged connections. This facilitates the smooth pressing of the water-stop structure and some components of the waler support device into the foundation pit soil. After the foundation pit soil is excavated to the appropriate depth for the installation of the top ring beam and waler, the support plate is installed at the ends of the connecting rods and telescopic rods, making the operation more convenient. Moreover, the water-stop structure and waler support device can be dismantled and recycled for reuse, saving project costs and causing less environmental pollution, thus achieving green construction.

[0012] Furthermore, the connecting rod of the waler support device consists of two horizontally arranged screws, screw one and screw two, with their axes coincident, and a sleeve that is fitted and threaded to the outside of screw one and screw two. The length of the sleeve is equal to the distance between the water-stop steel pipe and the waler. Screw one is vertically fixed to the water-stop steel pipe. The sleeve is fitted and threaded to screw one. One end of screw two is screwed into the sleeve and abuts against screw one. The length of screw two that is not screwed into the sleeve is equal to the depth of the internal threaded hole of the support plate. The other end of screw two is threaded to the support plate.

[0013] Furthermore, the telescopic rod of the diagonal brace consists of a sleeve hinged to the bearing seat and a support rod embedded in the sleeve, with the top end of the support rod abutting against the support plate; or, the telescopic rod of the diagonal brace consists of a hydraulic cylinder hinged to the bearing seat and a piston rod slidably connected to the hydraulic cylinder, with the other end of the piston rod abutting against the bottom of the support plate.

[0014] Furthermore, the top of the telescopic rod is also connected to a support plate, which also includes a groove plate with an L-shaped cross-section located on its edge away from the waterstop steel pipe, and the support plate is snapped into the groove formed by the groove plate.

[0015] Furthermore, the waler support device also includes multiple pressure sensors disposed on the four sides of the support plate, as well as an intelligent control system, which is connected to the pressure sensors and the hydraulic cylinder signals of the telescopic rod.

[0016] Furthermore, the cross-section of the water-stop steel plate is T-shaped, and both sides of the bored pile are provided with sockets. Each socket is composed of two symmetrical and spaced L-shaped steel plates. One end of the two L-shaped steel plates is welded to the reinforcing cage of the bored pile, and the gap between the other ends of the two L-shaped steel plates is equal to the thickness of the web of the water-stop steel plate. The web of the water-stop steel plate passes through the gap between the two L-shaped steel plates, and the flange of the water-stop steel plate is snapped into the socket, so that the water-stop structure can be interlocked with the adjacent discrete bored piles on both sides.

[0017] Furthermore, the water-stop structure also includes rubber water-stop strips symmetrically arranged on both sides of the web of the water-stop steel plate. The cross-section of the rubber water-stop strip is "V" shaped. Grooves are provided on both sides of the web of the water-stop steel plate. The clip at one end of the rubber water-stop strip is fastened to the groove, and the two support legs at the other end abut against the inside corner of the L-shaped steel plate and the included angle between the flange of the water-stop steel plate and the L-shaped steel plate, respectively.

[0018] In addition, the present invention also provides a construction method for a rigid foundation pit support system, the steps of which are as follows:

[0019] S1: Weld the connecting rods of multiple waler support devices and the bearing seats of the diagonal braces to one side of the waterstop steel pipe along the axis of the waterstop steel pipe. The number and position of the multiple waler support devices correspond to the actual number and position of the top ring beam and walers. Insert the waterstop steel plates on both sides of the waterstop steel pipe into the sockets of the adjacent bored piles on both sides, and press the waterstop structure into the foundation pit soil to the depth required for construction.

[0020] S2: After the foundation pit is excavated to the appropriate depth for the construction of the top ring beam or waler, the sleeve is fitted and threaded to the screw rod one. One end of the screw rod two is screwed into the sleeve and abuts against the screw rod one. The other end is screwed into the bottom of the threaded hole in the support plate. The bottom end of the telescopic rod is connected to the bearing seat, and its top end is supported on the bottom of the support plate. The top ring beam or waler is supported by multiple waler support devices located on the same horizontal plane. This process is repeated, and the top ring beam, waler and horizontal support are constructed layer by layer from top to bottom.

[0021] The construction method of the rigid foundation pit support system of the present invention involves pressing a water-stop structure equipped with multiple waler support devices into the foundation pit, with water-stop steel plates on both sides of the water-stop steel pipe inserted into the sockets of two adjacent bored piles. After the foundation pit soil is excavated to a suitable depth for the construction of the top ring beam or waler, the top ring beam or waler is supported by multiple waler support devices located on the same horizontal plane. This process is repeated, with the top ring beam, waler, and horizontal support constructed layer by layer from top to bottom. Water-stop structures equipped with waler support devices are inserted between the discrete bored piles. The structure forms an integrated foundation pit support system combining water-stopping and waler support. For discrete foundation pit support structures with water-stopping requirements, there is no need for a separate water-stop curtain, avoiding the water-stop curtain occupying construction space. This ensures the water-stopping effect of the foundation pit support system while effectively reducing project costs and shortening the construction period, which is beneficial for the construction of foundation pit support structures in confined land spaces. The number and location of the waler support devices are determined according to the actual number and location of the top ring beams and walers in the foundation pit, ensuring that the top ring beams and multiple walers in the foundation pit can be stably supported. The waler support device, fixedly mounted on one side of the water-stop structure, eliminates the need to remove concrete from the top and sides of the bored pile, and avoids the need for welded connections to the bored pile using hangers, corbels, or other structures. This not only ensures the integrity of the bored pile structure but also enables prefabricated construction of the foundation pit support system, improving construction efficiency, shortening the construction cycle, and offering good economic and safety benefits. The connecting rods, telescopic rods, and support plates of the waler support device are all movable connections, while the telescopic rods are hinged to the water-stop steel pipe, facilitating the connection of the water-stop structure. Some components of the waler support device were successfully pressed into the foundation pit soil. After the foundation pit soil was excavated to the appropriate depth for the installation of the top ring beam or waler, the support plate was installed at the end of the connecting rod and the telescopic rod, making the operation more convenient. Moreover, since the top ring beam, waler and horizontal support are supported in the foundation pit by the waler support device, the later dismantling is convenient and quick, avoiding secondary damage to the bored piles. The water-stop structure and waler support device after dismantling can be recycled and reused, saving project costs and causing less environmental pollution, thus achieving green construction.

[0022] Furthermore, step S1 also includes, after lowering the reinforcing cage of the bored pile into the borehole and before pouring concrete, pre-embedding bottom-sealed filler blocks in the two insertion holes on the side of the spiral stirrups of the reinforcing cage; embedding the clip at one end of the rubber waterstop into the groove of the web of the waterstop steel plate, and the two forked ends of the other end of the rubber waterstop abutting the inner corner of the L-shaped steel plate of the insertion hole and the included angle between the flange of the waterstop steel plate and the L-shaped steel plate.

[0023] Furthermore, step S2 also includes setting a pressure sensor on each of the four sides of the bottom of the support plate of each waler support device located at the same elevation, and the pressure sensors are all connected to the intelligent control system to monitor the pressure data of the support plates located at the same elevation in real time and transmit it to the intelligent control system. When the pressure value on one side of the support plate of the waler support device changes abruptly, the intelligent control system automatically drives the hydraulic structure of the corresponding telescopic rod to realize automatic compensation of the support axial force, so that the support plates of multiple waler support devices are on the same horizontal plane. Attached Figure Description

[0024] Figure 1 This is a structural schematic diagram of an embodiment of the rigid foundation pit support system of the present invention;

[0025] Figure 2 This is a schematic diagram of the structure of a waler support device according to an embodiment of the present invention;

[0026] Figure 3 This is a schematic diagram of the connection between the bored pile and the socket in one embodiment of the present invention;

[0027] Figure 4 This is a perspective view of the side insertion port of a bored pile in one embodiment of the present invention;

[0028] Figure 5 This is a schematic diagram of the water-stopping structure in one embodiment of the present invention;

[0029] Figure 6 This is a schematic diagram of the structure of the water-stop steel plate in one embodiment of the present invention;

[0030] Figure 7 This is a schematic diagram of the structure of a rubber waterstop in one embodiment of the present invention;

[0031] Figure 8 and Figure 9 This is a schematic diagram of each step in an embodiment of the construction method of the rigid foundation pit support system of the present invention.

[0032] The numbers in the diagram are as follows:

[0033] 1. Top ring beam; 2. First horizontal support; 3. First waler; 5. Second waler; 4. Second horizontal support; 6. Third horizontal support; 10. Drilled pile; 11. Reinforcing cage; 12. L-shaped steel plate; 14. Filler block; 15. Groove; 20. Waterstop structure; 21. Waterstop steel pipe; 24. Waterstop steel plate; 241. Web plate; 245. Flange plate; 246. Groove; 25. Rubber waterstop strip; 251. Clip; 252. Waler support device; 30. Screw rod 1; 32. Screw rod 2; 34. Sleeve; 35. Bearing seat; 36. Sleeve; 37. Support rod; 38. Support plate; 38a. Groove plate; 39. Support plate. Detailed Implementation

[0034] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clearly illustrate the embodiments of the present invention. For ease of description, the terms "upper" and "lower" used below are consistent with the upper and lower directions in the drawings, but this should not be construed as a limitation of the technical solution of the present invention.

[0035] This embodiment takes the construction of a foundation pit support system as an example. The inner side of the support structure is equipped with a top ring beam 1, a first waler 3, and a second waler 5 arranged at intervals from top to bottom. Three horizontal supports are correspondingly installed inside the foundation pit from top to bottom. The first horizontal support 2 is connected to the top ring beam 1, the second horizontal support 4 is connected to the first waler 3, and the third horizontal support 6 is connected to the second waler 5. The following is a combination of... Figures 1 to 7 This invention describes a rigid foundation pit support system, comprising: bored piles 10, a water-stop structure 20, and a waler support device 30. The water-stop structure 20 includes a water-stop steel pipe 21 and water-stop steel plates 24 vertically arranged on both sides of the water-stop steel pipe 21. The net distance between adjacent bored piles 10 meets the specifications and calculation requirements. The water-stop structure 20 is arranged between two adjacent bored piles 10. The water-stop steel plates 24 on both sides of the water-stop steel pipe 21 are respectively engaged with the bored piles 10 located on both sides. The tops of the bored piles 10 and the water-stop structure 20 are flush with the outdoor ground level. The water-stop steel pipe 21 is located near the foundation pit. Multiple waler support devices 30 are vertically and spaced apart along the side axis. The number and position of the waler support devices 30 correspond to the actual number and position of the top ring beam and walers in the foundation pit. Each waler support device 30 includes a connecting rod, a diagonal brace, and a support plate 38. The connecting rod and diagonal brace are vertically and spaced apart along the axis of the waterstop steel pipe 21. One end of the connecting rod is vertically fixed to the waterstop steel pipe 21, and the other end is movably connected to the support plate 38. The diagonal brace includes a bearing seat 35 and a telescopic rod hinged to it. The other end of the telescopic rod abuts against the bottom of the support plate 38. The waler support device 30 is used to support the top ring beam and walers in the foundation pit. In this embodiment, the width of the support plate 38 should be adapted to the width of the top ring beam or walers, and the length of the support plate 38 should be greater than or equal to the width of the horizontal support. Since the waterstop structure 20 does not need to bear the soil pressure outside the pit, its length only needs to meet the waterstop requirements and is not limited here.

[0036] The rigid foundation pit support system of the present invention includes bored piles 10, a water-stop structure 20 vertically arranged and interlocking with two adjacent bored piles 10, and a plurality of waler support devices 30 vertically and spaced apart on the pit-facing side of the water-stop structure 20. Each waler support device 30 includes connecting rods and diagonal braces vertically and spaced apart along the axis of the water-stop steel pipe 21, and support plates 38 respectively connected to both. One end of the connecting rod is vertically fixed to the water-stop steel pipe 21, and the other end is movably connected to the support plate 38. The diagonal brace includes a bearing seat 35 and a telescopic rod hinged thereto, with the other end of the telescopic rod abutting against the bottom of the support plate 38. This rigid foundation pit support system has at least the following beneficial effects:

[0037] 1. A water-stopping structure 20 with a waler support device 30 is inserted between discrete bored piles 10 to form a foundation pit support system that integrates water-stopping and waler support. For discrete foundation pit support structures with water interception requirements, there is no need to set up a separate water-stopping curtain, avoiding the water-stopping curtain from occupying underground construction space. This not only ensures the water-stopping effect of the foundation pit support system, but also effectively reduces the project cost and shortens the construction period, which is conducive to the construction of foundation pit support structures in narrow land space.

[0038] Second, multiple waler support devices 30 are vertically installed on the side of the water-stop steel pipe 21 of the water-stop structure 20. The number and position of the waler support devices 30 are determined according to the actual number and position of the top ring beam 1 and walers in the foundation pit. This ensures that the top ring beam 1 and multiple walers in the foundation pit can be stably supported by the waler support devices 30 on one side of the water-stop structure 20. There is no need to remove the concrete on the top and side of the bored pile 10, and there is no need to install hanging bars, corbels and other structures to weld to the bored pile 10. This not only ensures the integrity of the bored pile 10 structure, but also realizes the prefabricated construction of the foundation pit support system, improves construction efficiency, shortens the construction cycle, and has good economy and safety.

[0039] Third, the connecting rods, telescopic rods, and support plate 38 of the waler support device 30 are all movable connections, and the telescopic rods and water-stop steel pipe 21 are hinged connections. This facilitates the smooth pressing of the water-stop structure 20 and some components of the waler support device 30 into the foundation pit soil. After the foundation pit soil is excavated to the appropriate depth for the installation of the top ring beam 1 or the waler, the support plate 38 is installed at the ends of the connecting rods and telescopic rods, making the operation more convenient. Moreover, the water-stop structure 20 and the waler support device 30 can be disassembled and recycled, saving project costs and causing less environmental pollution, thus achieving green construction.

[0040] like Figure 2As shown, the connecting rod of the waler support device 30 consists of a horizontally arranged screw 31 and a screw 32 with their axes coincident, and a sleeve 34 that is sleeved and threaded to the outside of the screw 31 and the screw 32. The length of the sleeve 34 is equal to the distance between the water-stop steel pipe 21 and the waler. The screw 31 is vertically fixed to the water-stop steel pipe 21. The sleeve 34 is sleeved and threaded to the screw 31. One end of the screw 32 is screwed into the sleeve 34 and abuts against the screw 31. The length of the screw 32 that is not screwed into the sleeve 34 is equal to the depth of the internal threaded hole of the support plate 38. The other end of the screw 32 is threaded to the support plate 38. In this embodiment, the inner diameter of the sleeve 34 is the same as the outer diameter of the screw 1 31 and the screw 2 32. The length of the screw 2 32 is greater than the length of the screw 1 31. The length of the sleeve 34 is greater than or equal to the sum of the length of the screw 1 31 and half the length of the screw 2 32. During installation, the screw 1 31 is first vertically welded to the side of the waterstop steel pipe 21. The sleeve 34 is then fitted and threaded onto the screw 1 31 and pressed into the foundation pit soil along with the waterstop steel pipe 21. After the foundation pit soil is excavated to the appropriate depth suitable for the construction of the top ring beam 1 or the waler, one end of the screw 2 32 is screwed into the sleeve 34, and the other end is screwed into the bottom of the internal threaded hole of the support plate 38, so that the support plate 38 can be movably connected to the connecting rod and the support plate 38 can be accurately positioned.

[0041] like Figure 2 As shown, the telescopic rod of the diagonal brace consists of a sleeve 36 hinged to the bearing housing 35 and a support rod 37 embedded in the sleeve 36. The top end of the support rod 37 abuts against the support plate 38. During installation, the bearing housing 35 is first welded to the side of the waterstop steel pipe 21 and pressed into the foundation pit soil along with the waterstop steel pipe 21. After the foundation pit soil is excavated to the appropriate depth suitable for the construction of the top ring beam 1 or the waler, one end of the support rod 37 is installed on the bearing housing 35, and the other end is supported on the bottom of the support plate 38. In another embodiment, the telescopic rod of the diagonal brace consists of a hydraulic cylinder hinged to the bearing housing 35 and a piston rod slidably connected to the hydraulic cylinder. The other end of the piston rod abuts against the bottom of the support plate 38. By adjusting the length of the support rod 37 or the telescopic rod, the top end of the support rod 37 or the telescopic rod is made to be on the same horizontal plane as the connecting rod, ensuring that the support plate 38 can remain horizontal after installation.

[0042] like Figure 2 As shown, the bearing housing 35 includes a base and a pin fixed between two lugs of the base. One end of the telescopic rod is provided with a through hole that matches the pin. The pin passes through the through hole at the end of the telescopic rod and is inserted into the bearing housing 35, so that the telescopic rod can be hinged to the base, making installation and disassembly convenient and quick.

[0043] Please continue to refer to this. Figure 2To prevent the support plate 38 from falling, the top of the telescopic rod is also connected to a support plate 39. The support plate 38 also includes a groove plate 38a with an L-shaped cross-section, which is set on the edge away from the waterstop steel pipe 21. The size of the support plate 39 is much smaller than that of the support plate 38, but larger than the outer diameter of the support rod 37 or piston rod of the telescopic rod. The support plate 39 is snapped into the groove 15 formed by the groove plate 38a.

[0044] like Figure 3 and Figure 4 As shown, the cross-section of the water-stop steel plate 24 is T-shaped. Both sides of the bored pile 10 are provided with sockets. Each socket is composed of two symmetrical and spaced L-shaped steel plates 12. One end of the two L-shaped steel plates 12 is welded to the reinforcing cage 11 of the bored pile 10. The gap between the other ends of the two L-shaped steel plates 12 is equal to the thickness of the web 241 of the water-stop steel plate 24. The web 241 of the water-stop steel plate 24 passes through the gap between the two L-shaped steel plates 12. The flange 245 of the water-stop steel plate 24 is snapped into the socket, so that the water-stop structure 20 can be engaged and connected with the adjacent discrete bored piles 10 on both sides.

[0045] like Figure 5 , Figure 6 , Figure 7 and Figure 9 As shown, the water-stopping structure 20 also includes rubber water-stop strips 25 symmetrically arranged on both sides of the web 241 of the water-stopping steel plate 24. The cross-section of the rubber water-stop strip 25 is "V" shaped. Grooves 246 are provided on both sides of the web 241 of the water-stopping steel plate 24. The retaining strip 251 at one end of the rubber water-stop strip 25 is fastened to the groove 246, and the ends of the two supporting legs 252 at the other end abut against the inside corner of the L-shaped steel plate 12 of the insertion port and the included angle between the flange 245 of the water-stopping steel plate 24 and the L-shaped steel plate 12, respectively. The rubber water-stop strip 25, the L-shaped steel plate 12 of the insertion port, and the water-stopping steel plate 24 together form a closed space. Grouting can be performed on the gaps later to form a multi-layer water-stopping system, increasing the water seepage path and improving the water-stopping effect.

[0046] Furthermore, the waler support device 30 also includes multiple pressure sensors (not shown in the figure) disposed on the four sides of the support plate 39, as well as an intelligent control system. The intelligent control system is connected to the pressure sensors and the hydraulic cylinder signals of the telescopic rod. The pressure sensors are used to monitor the pressure data of the support plate 39 in real time and transmit it to the intelligent control system. When the pressure value on one side of the support plate 39 changes abruptly, the intelligent control system automatically drives the hydraulic structure of the telescopic rod to extend and retract to achieve automatic compensation of the support axial force, so that the pressure values ​​on the four sides of the support plate 39 are equal, ensuring the stability of the support plate 38.

[0047] Combination Figure 8 and Figure 9 The construction method of the rigid foundation pit support system of the present invention is described below, with specific steps as follows:

[0048] S1: Weld the connecting rods of multiple waler support devices 30 and the bearing seats 35 of the diagonal braces to one side of the waterstop steel pipe 21 along the axial direction of the waterstop steel pipe 21. The number and position of the multiple waler support devices 30 correspond to the actual number and position of the top ring beam 1 and the walers. Insert the waterstop steel plates 24 on both sides of the waterstop steel pipe 21 into the sockets of the adjacent bored piles 10 on both sides, and press the waterstop structure 20 into the foundation pit soil to the depth required for construction.

[0049] S2: After the foundation pit is excavated to the appropriate depth for the construction of the top ring beam 1 or the waler, the sleeve 34 is fitted and threaded to the screw rod 31. One end of the screw rod 32 is screwed into the sleeve 34 and abuts against the screw rod 31. The other end is screwed into the bottom of the threaded hole in the support plate 38. The bottom end of the telescopic rod is connected to the bearing seat 35, and its top end is supported on the bottom of the support plate 38. The top ring beam 1 or the waler is supported on multiple waler support devices 30 located on the same horizontal plane. This process is repeated, and the top ring beam 1, the waler and the horizontal support are constructed layer by layer from top to bottom.

[0050] The construction method of the rigid foundation pit support system of the present invention involves pressing a water-stopping structure 20 equipped with multiple waler support devices 30 into the foundation pit, and inserting the water-stopping steel plates 24 on both sides of the water-stopping steel pipe 21 into the sockets of two adjacent bored piles 10. After the foundation pit soil is excavated to a depth suitable for waler construction, the walers are supported by multiple waler support devices 30 located on the same horizontal plane. This process is repeated, with the walers and horizontal supports constructed layer by layer from top to bottom. The water-stopping structure 20 equipped with waler support devices 30 is inserted between the discrete bored piles 10, and... This system integrates water-stopping and waler support into a single foundation pit support system. For discrete foundation pit support structures with water interception requirements, there is no need for a separate water-stop curtain, avoiding the need for a separate water-stop curtain to occupy construction space. This ensures the water-stopping effect of the foundation pit support system while effectively reducing project costs and shortening the construction period, which is beneficial for the construction of foundation pit support structures in confined spaces. The number and location of the waler support devices 30 are determined according to the actual number and location of the top ring beam 1 and walers within the foundation pit, ensuring that the top ring beam 1 and multiple walers within the foundation pit can be stably supported by the water-stopping structure 20. The waler support device 30 on the side eliminates the need to remove the concrete from the top and sides of the bored pile 10, and eliminates the need for welding connections between the bored pile 10 and structures such as hangers and corbels. This not only ensures the structural integrity of the bored pile 10, but also enables prefabricated construction of the foundation pit support system, improving construction efficiency, shortening the construction cycle, and demonstrating good economy and safety. The connecting rods and telescopic rods of the waler support device 30 are all movable connections to the support plate 38, and the telescopic rods are hinged to the waterstop steel pipe 21, facilitating the connection between the waterstop structure 20 and the waler. Some components of the support device 30 were successfully pressed into the foundation pit soil. After the foundation pit soil was excavated to the appropriate depth for the installation of the top ring beam 1 or the waler, the support plate 38 was installed at the end of the connecting rod and the telescopic rod, making the operation more convenient. Moreover, since the top ring beam 1, the waler and the horizontal support are supported in the foundation pit by the waler support device 30, the later dismantling is convenient and quick, avoiding secondary damage to the bored pile 10. The water-stop structure 20 and the waler support device 30 after dismantling can be recycled and reused, saving project costs and causing less environmental pollution, thus achieving green construction.

[0051] Step S1 also includes, for example Figure 8As shown, after the reinforcing cage 11 of the bored pile 10 is lowered into the borehole and before the concrete is poured, a bottom-sealed filler block 14 is pre-embedded in the two insertion holes on the side of the spiral stirrup of the reinforcing cage 11. The width of the filler block 14 is less than or equal to the width of the L-shaped steel plate 12 to prevent the inner cavity enclosed by the insertion hole from being completely filled with concrete, which would make it difficult to insert the water-stop steel plate 24 later. Moreover, in order to prevent the filler block 14 from being raised by the concrete during the concrete pouring process of the bored pile 10, "C-shaped" slots 15 are set on both sides of the filler block 14. The top of the filler block 14 is locked into the insertion hole through the slots 15. The spacing of the slots 15 is slightly less than or equal to the sum of the thickness of the filler block 14 and the thickness of the L-shaped steel plate 12. After the concrete of the bored pile 10 is poured and reaches the design strength, the slots 15 are removed and the filler block 14 is pulled out. To facilitate the smooth removal of the filler block 14 later, an oil film can be pre-coated on the surface of the filler block 14. In this embodiment, the filling block 14 is preferably made of a rectangular plastic tube, and the slot 15 is preferably made of a wooden wedge. Of course, this is just an example and is not limited to this.

[0052] Step S1 also includes, for example Figure 9 As shown, the retaining strip 251 at one end of the rubber waterstop 25 is embedded into the groove 246 of the web plate 241 of the waterstop steel plate 24. The ends of the two forked legs 252 at the other end of the rubber waterstop 25 are respectively aligned with the inside corner of the L-shaped steel plate 12 and the included angle between the flange of the waterstop steel plate 24 and the L-shaped steel plate 12. The rubber waterstop 25, the L-shaped steel plate 12 of the socket and the waterstop steel plate 24 together form a closed space. Grouting can be performed on the gaps later to form a multi-layer waterstop system, which increases the water seepage path and improves the waterstop effect.

[0053] Step S2 further includes setting a pressure sensor on each of the four sides of the bottom of the support plate 39 of each waler support device 30 located at the same elevation. The pressure sensors are all connected to the intelligent control system to monitor the pressure data of the support plate 39 located at the same elevation in real time and transmit it to the intelligent control system. When the pressure value of the support plate 39 of a certain waler support device 30 or a certain side of the support plate 39 changes abruptly, the intelligent control system automatically drives the hydraulic structure of the corresponding telescopic rod to realize automatic compensation of the support axial force, so that the pressure values ​​on the four sides of the support plate 39 are equal, and ensure that the support plates 38 of multiple waler support devices 30 are on the same horizontal plane, thereby providing stable support for the waler.

[0054] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the scope of the claims.

Claims

1. A rigid foundation pit support system, characterized in that, include: The system comprises bored piles, a water-stop structure, and waler support devices. The water-stop structure includes a water-stop steel pipe and water-stop steel plates vertically arranged on both sides of the water-stop steel pipe. The water-stop structure is installed between two adjacent bored piles. The water-stop steel plates on both sides of the water-stop steel pipe are respectively engaged with the bored piles located on both sides. The tops of the bored piles and the water-stop structure are flush with the outdoor ground level. Multiple waler support devices are vertically arranged at intervals along the axial direction on the side of each water-stop steel pipe near the foundation pit. The number and position of the supporting devices correspond to the actual number and position of the top ring beam and walers in the foundation pit. The waler supporting device includes connecting rods, diagonal braces and supporting plates. The connecting rods and diagonal braces are arranged vertically and at intervals along the axis of the waterstop steel pipe. One end of the connecting rod is vertically fixed to the waterstop steel pipe, and the other end is movably connected to the supporting plate. The diagonal brace includes a bearing seat and a telescopic rod hinged to it. The other end of the telescopic rod abuts against the bottom of the supporting plate. The waler supporting device is used to support the top ring beam and walers in the foundation pit. The connecting rod of the waler support device consists of two horizontally arranged screw rods, screw rod one and screw rod two, and a sleeve that is sleeved and threaded to the outside of screw rod one and screw rod two. The length of the sleeve is equal to the distance between the water-stop steel pipe and the waler. Screw rod one is vertically fixed to the water-stop steel pipe. The sleeve is sleeved and threaded to screw rod one. One end of screw rod two is screwed into the sleeve and abuts against screw rod one. The length of screw rod two that is not screwed into the sleeve is equal to the depth of the internal threaded hole of the support plate. The other end of screw rod two is threaded to the support plate.

2. The rigid foundation pit support system according to claim 1, characterized in that: The telescopic rod of the diagonal brace consists of a hydraulic cylinder hinged to the bearing seat and a piston rod slidably connected to the hydraulic cylinder, with the other end of the piston rod abutting against the bottom of the support plate.

3. The rigid foundation pit support system according to claim 1, characterized in that: The top of the telescopic rod is also connected to a support plate, which also includes a groove plate with an L-shaped cross-section located on the side of the support plate away from the waterstop steel pipe, and the support plate is snapped into the groove formed by the groove plate.

4. The rigid foundation pit support system according to claim 3, characterized in that: The waler support device also includes multiple pressure sensors installed on the four sides of the support plate, as well as an intelligent control system. The intelligent control system is connected to the pressure sensors and the hydraulic cylinder signals of the telescopic rod, respectively.

5. The rigid foundation pit support system according to claim 1, characterized in that: The cross-section of the water-stop steel plate is T-shaped. Both sides of the bored pile are provided with sockets. Each socket consists of two symmetrical and spaced L-shaped steel plates. One end of the two L-shaped steel plates is welded to the reinforcing cage of the bored pile. The gap between the other ends of the two L-shaped steel plates is equal to the thickness of the web of the water-stop steel plate. The web of the water-stop steel plate passes through the gap between the two L-shaped steel plates. The flange of the water-stop steel plate is snapped into the socket, so that the water-stop structure can be interlocked with the adjacent discrete bored piles on both sides.

6. The rigid foundation pit support system according to claim 5, characterized in that: The water-stop structure also includes rubber water-stop strips symmetrically arranged on both sides of the web of the water-stop steel plate. The cross-section of the rubber water-stop strip is "human" shaped. Grooves are provided on both sides of the web of the water-stop steel plate. The clip at one end of the rubber water-stop strip is fastened to the groove, and the two support legs at the other end abut against the inside corner of the L-shaped steel plate and the included angle between the flange of the water-stop steel plate and the L-shaped steel plate, respectively.

7. The construction method of the rigid foundation pit support system as described in any one of claims 1 to 6, characterized in that, The steps are as follows: S1: Weld the connecting rods of multiple waler support devices and the bearing seats of the diagonal braces to one side of the waterstop steel pipe along the axis of the waterstop steel pipe. The number and position of the multiple waler support devices correspond to the actual number and position of the top ring beam and walers. Insert the waterstop steel plates on both sides of the waterstop steel pipe into the sockets of the adjacent bored piles on both sides, and press the waterstop structure into the foundation pit soil to the depth required for construction. S2: After the foundation pit is excavated to the appropriate depth for the construction of the top ring beam or waler, the sleeve is fitted and threaded to the screw rod one. One end of the screw rod two is screwed into the sleeve and abuts against the screw rod one. The other end is screwed into the bottom of the threaded hole in the support plate. The bottom end of the telescopic rod is connected to the bearing seat, and its top end is supported on the bottom of the support plate. The top ring beam or waler is supported by multiple waler support devices located on the same horizontal plane. This process is repeated, and the top ring beam, waler and horizontal support are constructed layer by layer from top to bottom.

8. The construction method of the rigid foundation pit support system according to claim 7, characterized in that: Step S1 further includes, after lowering the reinforcing cage of the bored pile into the borehole and before pouring concrete, pre-embedding bottom-sealed filler blocks in the two insertion holes on the side of the spiral stirrups of the reinforcing cage; embedding the clip at one end of the rubber waterstop into the groove of the web of the waterstop steel plate, and the two forked ends of the other end of the rubber waterstop abutting the inner corner of the L-shaped steel plate of the insertion hole and the included angle between the flange of the waterstop steel plate and the L-shaped steel plate.

9. The construction method of the rigid foundation pit support system according to claim 7, characterized in that: Step S2 further includes setting a pressure sensor on each of the four sides of the bottom of the support plate of each waler support device located at the same elevation, and the pressure sensors are all connected to the intelligent control system to monitor the pressure data of the support plates located at the same elevation in real time and transmit it to the intelligent control system. When the pressure value on one side of the support plate of the waler support device changes abruptly, the intelligent control system automatically drives the hydraulic structure of the corresponding telescopic rod to realize automatic compensation of the support axial force, so that the support plates of multiple waler support devices are on the same horizontal plane.

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