A civil air defense project foundation pit support structure and construction method thereof

Abstract

The present application relates to the technical field of engineering construction, and in particular to a foundation pit support structure for civil air defense engineering and a construction method thereof, which includes: a foundation, which is laid at the bottom of the foundation pit and is used to form a construction surface; a plurality of foundation piles, which are formed at the bottom of the foundation pit and connected to the foundation, and are used to support the foundation; a seepage and drainage mechanism, which includes a plurality of seepage and drainage piles arranged at the bottom of the foundation pit, a plurality of the seepage and drainage piles corresponding to a plurality of the foundation piles are staggered and extended to the aquifer, the seepage and drainage piles penetrate the foundation and form a water storage cavity, and the seepage and drainage piles form a seepage and drainage mesh connected to the water storage cavity; a waterproof layer, a hydrophobic layer and a cushion layer are laid in sequence on the lower layer of the foundation; a water-stop curtain is formed in the soil layer and is arranged around the foundation; a side retaining wall is arranged on the foundation and is used to protect the side of the foundation pit. The present application has the effect of reducing water seepage in the foundation pit and reducing the impact on the quality of the building.

Description

Technical Field

[0001] The present application relates to the technical field of engineering construction, and in particular to a foundation pit support structure for a civil air defense project and a construction method thereof. Background Art

[0002] At present, foundation pit refers to a deep pit or large hole dug in the ground for the construction of buildings or other projects. Usually, foundation pits are excavated to build underground structures, such as basements, parking lots, underground passages, etc., or to bury underground facilities such as pipelines and caissons. The depth and shape of foundation pits can vary according to the needs of specific projects. They are usually fenced to ensure safety and stability, and corresponding support and drainage measures are taken during construction.

[0003] When there is a pressurized aquifer at the bottom of a deep foundation pit, excavation of the foundation pit will reduce the thickness of the impermeable layer overlying the aquifer. When the thickness of the impermeable layer is reduced to a certain extent, the head pressure of the pressurized water can crack or destroy the foundation soil of the foundation pit, causing great difficulties for the construction. At present, the foundation is usually reinforced by tamping the foundation and / or supporting piles. However, for foundation pits in water-rich areas, water will still flow to the soil below the foundation pit and gather in the pressurized aquifer. When the water pressure rises, it will cause water seepage or damage to the foundation, affecting the quality of the building. Summary of the invention

[0004] In order to reduce water seepage in foundation pit and reduce the impact on building quality, the present application provides a foundation pit support structure for a civil air defense project and a construction method thereof.

[0005] In the first aspect, the present application provides a foundation pit support structure for civil air defense projects, which adopts the following technical solutions:

[0006] A foundation pit support structure for civil air defense engineering, comprising:

[0007] The foundation is laid at the bottom of the foundation pit to form the construction surface;

[0008] A plurality of foundation piles are provided, formed at the bottom of the foundation pit and connected to the foundation, and used to support the foundation;

[0009] The seepage drainage mechanism comprises a plurality of seepage drainage piles arranged at the bottom of the foundation pit, the plurality of the seepage drainage piles are arranged in a staggered manner corresponding to the plurality of the foundation piles and extend to the aquifer, the seepage drainage piles penetrate the foundation and form a water storage cavity, and the seepage drainage piles are formed with seepage drainage mesh holes connected to the water storage cavity; the lower layer of the foundation is sequentially paved with a water-isolating layer, a hydrophobic layer and a cushion layer;

[0010] a water-stop curtain formed in the soil layer and arranged around the foundation;

[0011] Side retaining walls are installed on the foundation and are used to protect the sides of the foundation pit.

[0012] By adopting the above technical scheme, the water in the aquifer enters the seepage and drainage piles through the seepage and drainage mesh holes of the seepage and drainage piles, reducing the rise in water pressure in the aquifer. The set water-stop curtain can play a certain water-isolating role, reduce the inflow of external water sources, and slow down the rate of water pressure rise in the aquifer. At the same time, the waterproof layer can play a water-isolating role, reduce water seepage from the foundation, reduce damage to the foundation, reduce foundation seepage, and at the same time reduce the impact on building quality.

[0013] Optionally, the hydrophobic layer is arranged at an angle to gather water at the drainage piles.

[0014] By adopting the above technical solution, when water seeps up to the hydrophobic layer, the hydrophobic layer is inclined to facilitate the diversion of water to the drainage piles, thereby reducing further water infiltration, reducing the probability of foundation seepage, and further reducing damage to the foundation.

[0015] Optionally, a block net is provided between the foundation piles and the drainage piles.

[0016] By adopting the above technical solution and setting up the block net, the ground can be reinforced in blocks, which helps to improve the stability of the foundation, while reducing water and soil loss, and connecting adjacent drainage piles and foundation piles to improve stability.

[0017] Optionally, a plurality of grouting pipes are provided on the foundation piles, and the grouting pipes are arranged along the length direction of the foundation piles.

[0018] By adopting the above technical solution, slurry is poured into the soil layer through the grouting pipe, which makes it easy to fill the gaps in the soil layer, and can play a certain role in preventing water seepage. It can also fill the gaps in the block network, reduce the formation of water flow channels, improve the stability of the foundation, and further reduce the possibility of damaging the foundation.

[0019] Optionally, a grouting branch pipe is spirally wound on the block net in a direction away from the foundation, and a plurality of overflow holes are opened on the grouting branch pipe.

[0020] By adopting the above technical solution, during grouting, part of the slurry extends to the block net and the inside of the soil layer through the grouting branch pipe, making the soil layer more fully filled, reducing the chance of water seeping upward from the aquifer, and reducing damage to the abutment. In addition, the setting of the grouting branch pipe makes the slurry fill the block net more tightly, making the block net more strongly bound to the soil layer, which can reduce soil erosion and reduce the appearance of holes in the lower layer of the foundation.

[0021] Optionally, the drainage pile comprises:

[0022] The outer pipe is buried in the soil layer and passes through the aquifer of the soil layer. The pipe section located in the aquifer is a permeable pipe, and the outer side of the permeable pipe is covered with a geotextile.

[0023] The inner tube is inserted into the outer tube, and there is a gap between the inner tube and the outer tube, and clay is filled between the outer tube and the inner tube. A water storage cavity is formed in the inner tube, and a mesh hole for connecting the water storage cavity and the infiltration tube is opened in the pipe section located in the aquifer, and a filter screen is attached to the mesh hole, and the filter screen has elasticity;

[0024] a drainage assembly, disposed in the inner tube and extending to the upper layer of the foundation;

[0025] The one-way reverse osmosis plate is arranged at the bottom of the outer tube and blocks the water storage cavity so as to allow the water in the water storage cavity to penetrate into the lower soil layer.

[0026] By adopting the above technical scheme, water in the aquifer enters the gap between the inner tube and the outer tube through the infiltration tube, and then enters the water storage chamber through the filter screen, reducing the rise of water pressure in the aquifer, and then infiltrates into the lower soil layer through the one-way reverse osmosis plate, reducing bulging and cracking of the foundation caused by excessive water pressure in the aquifer, reducing the rapid rise of the water level in the water storage chamber, reducing the water infiltration caused by the rise of the liquid level, and improving the stability of the foundation. Through the drainage component, water exceeding a certain water level is discharged, so that the pressurized water maintains a certain pressure-bearing effect, thereby improving the stability of the coating.

[0027] Optionally, the pipe section of the inner pipe located in the aquifer is a first steel pipe, and a support assembly is arranged outside the first steel pipe, and the support assembly includes:

[0028] At least three vertical ribs are provided, which are parallel to the axis of the inner tube and are arranged at intervals along the circumference of the inner tube, abutting against the permeation tube and supporting the permeation tube;

[0029] A plurality of annular ribs are provided, connected to the vertical ribs, and abut against the permeation tubes.

[0030] By adopting the above technical solution, the vertical reinforcement and the annular reinforcement form a supporting component with the first steel pipe to support the permeable tube, reduce the squeezing of the soil layer and the aquifer on the permeable tube, reduce the damage to the permeable tube, and maintain the pressure relief effect on the aquifer.

[0031] Optionally, the drainage component includes:

[0032] A second steel pipe is inserted into the inner pipe and extends above the one-way reverse osmosis plate, and one end away from the one-way reverse osmosis plate is connected to a drainage pump through a hose;

[0033] a positioning ring, disposed on the second steel pipe and slidably connected to the second steel pipe;

[0034] A positioning block is arranged on the second steel pipe and is used for supporting the positioning ring.

[0035] By adopting the above technical solution, when the water level in the water storage chamber rises, the water level in the water storage chamber is lowered through the drainage pump and the second steel pipe, so that the pressure relief effect on the aquifer is maintained; the provided positioning ring and positioning block play a role in fixing and positioning the second steel pipe, which can reduce the damage to the one-way reverse osmosis plate caused by the sinking of the second steel pipe, and at the same time make the second steel pipe located in the middle of the inner pipe.

[0036] Optionally, a floating component and a disturbance component are provided on the second steel pipe, and the floating component includes:

[0037] A counterweight ring is sleeved and slidably mounted on the second steel pipe, with a gap between the counterweight ring and the second steel pipe;

[0038] A floating ball is arranged on the counterweight ring and is located on a side of the counterweight ring close to the one-way reverse osmosis plate, and drives the counterweight ring to move upward as the water level rises;

[0039] A sensor is arranged on the second steel pipe, and water is pumped when the counterweight ring abuts against the sensor;

[0040] Bristles are arranged on the counterweight ring and extend to the filter screen;

[0041] The disturbance component comprises: a disturbance pipe, which is arranged on the second steel pipe, extends to the position of the one-way reverse osmosis plate, and is connected to a disturbance pump through a hose.

[0042] By adopting the above technical solution, when the water level rises, the float drives the counterweight ring to rise, the counterweight ring abuts against the sensor, the sensor is triggered, the drainage pump starts, and the water in the water storage chamber is discharged. At the same time, the counterweight ring descends, so that the bristles clean the filter, so that the water passing effect of the filter is maintained; and the disturbance component disturbs the water, causing the liquid level to fluctuate, thereby causing the float and the counterweight ring to shake, thereby making the fluctuation of the filter and the disturbance of the water flow more intense, which facilitates the shaking of the water between the outer tube and the inner tube and the water in the water storage chamber, so that the water permeability of the filter is maintained.

[0043] In the second aspect, the present application provides a construction method for a foundation pit support structure for a civil air defense project, which adopts the following technical solution:

[0044] A construction method for a foundation pit support structure of a civil air defense project comprises the following steps:

[0045] S1. Excavation of foundation pit, geological survey, and excavation of foundation pit according to the geological survey results;

[0046] S2, pile foundation construction, construction of water-stop curtain, excavation of foundation pile holes, steel bar layout, formwork erection, and pouring construction;

[0047] S3, drainage construction, excavation of drainage pile holes, lowering the outer pipe of the drainage pile to pass through the aquifer, then installing the inner pipe, filling the gap between the inner pipe and the outer pipe, and then installing the drainage assembly;

[0048] S4, grouting, installing the block net and performing grouting;

[0049] S5, foundation construction, laying the cushion layer, water-repellent layer, waterproof layer and foundation on the upper layer of the ground in sequence;

[0050] S6. Side retaining wall construction: formwork support is carried out on the outer edge of the foundation pit on the foundation surface, and the side retaining wall is cast and formed.

[0051] By adopting the above technical scheme, when constructing the support structure, first conduct an address survey, excavate the foundation pit according to the geological survey, then determine the construction scope according to the construction design, then construct the water-stop curtain, and excavate the foundation pile holes, then lay out the steel bars, support the formwork, and then carry out the pouring construction, using high-strength impermeable concrete for pouring; then excavate the drainage pile holes, then install the outer pipe, then carry out the lower part of the inner pipe, and after the lower part is completed, Fill the gap between the outer tube and the inner tube above the infiltration tube, then install the drainage assembly, then install the block net, and after the installation of the block net, perform grouting; then lay the cushion layer, hydrophobic layer, waterproof layer and foundation in sequence, and then construct the side retaining wall; through the above construction method, the strength of the support structure is higher, and the damage of the underground aquifer to the foundation can be reduced, the water pressure can be released in time, and when the water level is too high, drainage can be carried out to reduce the holes in the lower layer of the foundation, and soil and water loss can be effectively reduced.

[0052] In summary, the present application includes at least one of the following beneficial technical effects:

[0053] 1. The water in the aquifer enters the seepage and drainage piles through the seepage and drainage mesh holes of the seepage and drainage piles, reducing the rise in water pressure in the aquifer. The installed water-stop curtain can play a certain role in water isolation, reduce the inflow of external water sources, and slow down the rate of water pressure rise in the aquifer. At the same time, the water-blocking layer can play a role in water isolation, reduce water seepage from the foundation, reduce damage to the foundation, reduce foundation seepage, and reduce the impact on building quality;

[0054] 2. The water in the aquifer enters the gap between the inner tube and the outer tube through the infiltration tube, and then enters the water storage cavity through the filter screen, reducing the rise of water pressure in the aquifer, and then infiltrates into the lower soil layer through the one-way reverse osmosis plate, reducing the bulging and cracking of the foundation caused by excessive water pressure in the aquifer, and reducing the rapid rise of the water level in the water storage cavity, reducing the water infiltration caused by the rise of the liquid level, improving the stability of the foundation, and through the drainage component, the water exceeding a certain water level is discharged, so that the pressurized water maintains a certain pressure-bearing effect, and improves the stability of the coating;

[0055] 3. When the water level rises, the float drives the weight ring to rise, and the weight ring contacts the sensor. The sensor is triggered, the drainage pump starts, and the water in the water storage chamber is discharged. At the same time, the weight ring drops, allowing the bristles to clean the filter, so that the water passing effect of the filter can be maintained. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 It is an overall structural diagram of the foundation pit support structure in the embodiment of the present application;

[0057] Figure 2 It is a display diagram of the seepage and drainage mechanism in the embodiment of the present application;

[0058] Figure 3 yes Figure 2 A magnified view of middle;

[0059] Figure 4 yes Figure 3 Enlarged view of middle B;

[0060] Figure 5 This is a diagram showing the position of the disturbance tube in an embodiment of the present application.

[0061] Reference numerals: 100, foundation; 200, foundation pile; 300, seepage drainage mechanism; 310, seepage drainage pile; 311, outer pipe; 312, inner pipe; 313, one-way reverse seepage plate; 314, seepage pipe; 315, first steel pipe; 316, filter screen; 317, support ring; 320, drainage assembly; 321, second steel pipe; 322, positioning ring; 323, positioning block; 330, support assembly; 331, vertical rib; 332, Annular reinforcement; 340, floating assembly; 341, counterweight ring; 342, floating ball; 343, sensor; 344, bristles; 345, limit ring; 350, disturbance assembly; 351, disturbance tube; 360, sealing ball; 370, positioning rod; 500, side retaining wall; 610, block net; 620, grouting pipe; 630, grouting branch pipe; 640, waterproof layer; 650, hydrophobic layer; 660, cushion layer; 700, aquifer. DETAILED DESCRIPTION

[0062] The following combination Figures 1 to 5 This application is described in further detail.

[0063] This embodiment discloses a construction method for a foundation pit support structure of a civil air defense project.

[0064] refer to Figure 1 , the construction method of the foundation pit support structure of the civil air defense project includes the following steps:

[0065] S1. Excavation of foundation pit, geological survey, and excavation of foundation pit according to the geological survey results;

[0066] Specifically, according to the construction organization design, an on-site geological survey is conducted to determine the excavation depth and the laying range of the foundation 100 and the foundation piles 200, and then the foundation pit is excavated.

[0067] S2, pile foundation construction, construction of water-stop curtain, excavation of 200 holes of foundation piles, steel bar layout, formwork erection, and pouring construction;

[0068] Specifically, before the pile foundation construction, the construction scope of the water-stop curtain is determined according to the construction scope of the foundation 100. At the same time, the depth and thickness of the water-stop curtain are determined according to the underground rock and soil structure. Then the water-stop curtain is constructed, and then the holes of the pile foundation 200 are excavated. The construction of the pile foundation can determine whether formwork support is required based on the actual situation on site or the construction organization design. After the hole excavation is completed, the steel bars are laid, and then support or pouring is carried out. Before support or pouring, the holes are first cleaned to reduce the presence of debris and gravel. When pouring the pile foundation 200, a grouting pipe 620 is installed on the outside of the formwork. The grouting pipe 620 is located on the outer edge of the pile foundation 200 and is connected to the steel mesh of the pile foundation 200. It can be used to grout the soil layer after the pouring of the pile foundation 200 is completed.

[0069] S3, seepage drainage construction, the holes of the seepage drainage pile 310 are excavated, the outer pipe 311 of the seepage drainage pile 310 is lowered to pass through the aquifer 700, and then the inner pipe 312 is installed, and the gap between the inner pipe 312 and the outer pipe 311 is filled, and then the drainage assembly 320 is installed;

[0070] refer to Figures 2 to 4Specifically, the seepage drainage mechanism 300 is constructed. The seepage drainage mechanism 300 includes a plurality of seepage drainage piles 310 arranged at the bottom of the foundation pit. First, the holes of the seepage drainage piles 310 are excavated. The seepage drainage piles 310 include an outer pipe 311 buried in the holes of the seepage drainage piles 310 in the soil layer. Multiple layers of stones with different gaps are filled between the holes of the seepage drainage piles 310, and the upper layer is cast and fixed with concrete; the outer pipe 311 passes through the aquifer 700 of the soil layer, and the stones with different gaps completely cover the aquifer 700. 0, and the particle size of the gravel close to the outer tube 311 is smaller than the particle size of the gravel far away from the outer tube 311, the pipe section of the outer tube 311 located in the aquifer 700 is a permeable pipe 314, the diameter of one end of the outer tube 311 passing through the aquifer 700 is smaller than the diameter of the permeable pipe 314, and a supporting ring 317 is fixedly connected; the outer side of the permeable pipe 314 is covered with geotextile, and the permeable pipe 314 can be made of a concrete pipe with water seepage function or a plastic seepage pipe, a metal seepage pipe or other pipes with water seepage function.

[0071] The inner tube 312 is inserted into the outer tube 311, and a plurality of positioning rods 370 are fixedly connected to the outer wall of the inner tube 312. The positioning rods 370 abut against the inner wall of the outer tube 311 to adjust the inner tube 312 to be concentric with the outer tube 311. The inner tube 312 is inserted into the outer tube 311 and abuts against the support ring 317. One end of the inner tube 312 close to the support ring 317 is installed with water-swellable rubber, and the surface is wrapped with a water-soluble environmental protection film. After being immersed in water for three hours, the water The soluble environmental protection film melts, so that the water and the water-swellable rubber fully contact and expand and press against the outer tube 311; the diameter of the inner tube 312 is smaller than the diameter of the outer tube 311, and there is a gap of at least 12 cm between the inner tube 312 and the outer tube 311. The sealing ball 360 is filled in the gap, and the water level rises, so that the position of the sealing ball 360 is higher than the aquifer 700, and then clay is filled to reduce the excessive water level of the aquifer 700 staying in the gap between the inner tube 312 and the outer tube 311 ; The inner tube 312 is a tubular structure with a central hole, and a water storage cavity is formed in the inner tube 312. The pipe sections corresponding to the inner tube 312 and the permeation tube 314 are first steel tubes 315 made of stainless steel or other materials that are not easy to rust. The first steel tube 315 is provided with a plurality of infiltration and drainage mesh holes, which are connected to the water storage cavity. A filter 316 is installed on the mesh holes, and the filter 316 is elastic; the water in the aquifer 700 passes through the preliminary infiltration and filtration of the permeation tube 314, enters the gap between the inner tube 312 and the outer tube 311, and then enters the water storage cavity through the filtration of the filter 316; by using a water-soluble environmentally friendly film, the water-swelling rubber is reduced from swelling due to premature contact with water, the impact on installation is reduced, and there is no harmful substance, which reduces the pollution of water resources. At the same time, the water-soluble environmentally friendly film decomposes and melts to cause microorganisms to aggregate and decompose, which is convenient for reducing the precipitation of water between the outer tube 311 and the inner tube 312 and reducing the blockage of the filter 316.

[0072] A one-way reverse osmosis plate 313 is fixedly connected to the inner wall of the inner tube 312. The one-way reverse osmosis plate 313 is located at the lower end of the water storage chamber. The water in the water storage chamber penetrates toward the lower soil layer through the one-way reverse osmosis plate 313, thereby reducing the penetration of the lower soil layer into the water storage chamber.

[0073] The inner tube 312 is provided with a drainage assembly 320, which extends to the upper layer of the foundation 100 and is used to drain the water in the water storage cavity. The drainage assembly 320 includes a second steel pipe 321, which is plugged into the inner tube 312 and located in the water storage cavity. A positioning ring 322 is fixedly connected to the second steel pipe 321, and a positioning block 323 is fixedly connected to the wall of the inner tube 312. The side of the positioning block 323 away from the one-way reverse osmosis plate 313 is connected to the positioning ring 322. The positioning ring 322 is in contact with the side wall of the one-way reverse osmosis plate 313, and the positioning block 323 is used to position the positioning ring 322 and limit the second steel pipe 321 from contacting the one-way reverse osmosis plate 313. The positioning ring 322 is in the shape of a truncated cone, and the end with a small area is inserted into the positioning block 323; the second steel pipe 321 extends to the foundation 100 through a hose and is connected to a drainage pump. A quick connector can be provided on the hose. When not in use, the inner tube 312 can be closed by removing the quick connector.

[0074] The second steel tube 321 is also provided with a floating assembly 340, which includes a weight ring 341 which is sleeved and slidably mounted on the second steel tube 321. There is a gap between the weight ring 341 and the second steel tube 321, and the gap is 5 mm on one side. A floating ball 342 is fixedly connected to the weight ring 341. The floating ball 342 can be a rubber material such as a swimming ring or a spherical shape filled with gas and can float on the water. The floating ball 342 is located on one side of the weight ring 341 close to the one-way reverse osmosis plate 313. The outer edge of the weight ring 341 is fixedly connected with bristles 344, which are made of soft material. As the weight ring 341 moves up and down, the bristles 344 are fixedly connected to the outer edge of the weight ring 341. The bristles 344 are made of soft material. As the weight ring 341 moves up and down, the floating ball 342 is fixedly connected to the second steel tube 321. The bristles 344 scrape the filter screen 316; a limit ring 345 is fixedly connected to the second steel pipe 321, and the limit ring 345 can abut against the counterweight ring 341 to reduce the separation of the counterweight ring 341 and the second steel pipe 321; in order to promptly detect the rise of the water level or perform drainage work in time, a sensor 343 is provided on the second steel pipe 321, and the sensor 343 is a contact sensor 343. The counterweight ring 341 rises with the float 342 and can abut against the sensor 343. The sensor 343 is triggered to send a pumping signal, or the sensor 343 is connected to the drainage pump, and the drainage pump starts and continues to pump water for a certain period of time.

[0075] Reference Figure 2 and Figure 5A disturbance assembly 350 is provided on the second steel pipe 321, and the disturbance assembly 350 includes a plurality of disturbance tubes 351, which are fixedly connected to the second steel pipe 321 and are arranged at equal intervals around the circumference of the second steel pipe 321. The outer diameter of the disturbance tube 351 can be tangent to the inner wall of the second steel pipe 321 or the outer wall of the second steel pipe 321, and can be set according to the actual application environment. The disturbance tube 351 extends to the upper side of the foundation 100 through a hose and is connected to a disturbance pump, which is used to supply air to the disturbance tube 351.

[0076] In order to reduce the damage and deformation of the permeation tube 314 caused by extrusion, a support assembly 330 is arranged on the second steel tube 321. The support assembly 330 includes a plurality of vertical ribs 331 fixedly connected to the second steel tube 321. There are at least three vertical ribs 331, and three are preferably provided in this embodiment. The three vertical ribs 331 are evenly spaced along the circumference of the second steel tube 321. The vertical ribs 331 abut against the inner wall of the permeation tube 314. The three vertical ribs 331 are fixedly connected by annular ribs 332. Multiple annular ribs 332 can be provided. Two are preferably provided in this embodiment. The environment abuts against the inner wall of the permeation tube 314.

[0077] After the outer tube 311 is installed, the inner tube 312 is lowered in sequence, the weight ring 341 , the float 342 and the disturbance tube 351 are installed on the second steel tube 321 in sequence, and then the second steel tube 321 is installed.

[0078] S4, grouting, installing the block net 610 and performing grouting;

[0079] Specifically, a groove of the block net 610 is dug between the foundation pile 200 and the drainage pile 310, and then the block net 610 is lowered, and then the block net 610 is connected to the foundation pile 200 and the drainage pile 310, and a grouting branch pipe 630 is arranged on the block net 610, and the grouting branch pipe 630 is spirally arranged along the block net 610, one end of which is connected to the grouting pipe 620, and the end away from the grouting pipe 620 is inclined in the direction away from the foundation 100; then the soil is filled into the groove of the block net 610 and compacted, and finally the grouting operation is performed.

[0080] S5, construction of foundation 100, laying cushion layer 660, hydrophobic layer 650, waterproof layer 640 and foundation 100 in sequence on the upper layer of the ground;

[0081] Specifically, first, a cushion layer 660 is laid on the surface of the soil layer. The cushion layer 660 can be laid with materials such as fine sand, gravel, solid waste, etc., with a laying thickness of about 10 cm. Then, the water layer is laid. The hydrophobic layer 650 uses graded gravel and is laid from bottom to top in ascending order, and is laid obliquely. The height close to the drainage pile 310 is lower than the height at other positions, and the outer tube 311 and the inner tube 312 of the drainage pile 310 corresponding to the position of the hydrophobic layer 650 are both made of permeable materials, so that the hydrophobic layer 650 can guide water into the water storage cavity. The laying thickness of the hydrophobic layer 650 is 12 cm; a waterproof layer 640 is laid on the hydrophobic layer 650. The thickness of the waterproof layer 640 is 3 cm. The waterproof layer 640 is made of waterproof material and anti-seepage material to reduce the upward infiltration of bottom water. Then, the foundation 100 is laid.

[0082] S6, side retaining wall construction, formwork support is carried out on the outer edge of the foundation pit on the surface of the foundation 100, and the side retaining wall 500 is cast and formed.

[0083] Specifically, after the foundation 100 is poured, it is cured and then the side retaining wall 500 is constructed. When the side retaining wall 500 is constructed, the steel mesh is first constructed, then the formwork support is performed, and then concrete is poured to form the side retaining wall 500.

[0084] The implementation principle of a construction method of a foundation pit support structure for a civil air defense project in an embodiment of the present application is as follows: according to the construction organization design, geological survey is carried out to determine the excavation depth, and then excavation is carried out. After the excavation is completed, a water-stop curtain is constructed, and then holes for foundation piles 200 are drilled on the ground, and then steel bars are laid, formwork support is carried out, and then concrete is poured. Then holes for drainage piles 310 are drilled on the ground, and outer pipes 311 are lowered into the holes. Then, grooves for the block net 610 can be excavated at the same time, and the block net 610 is lowered, and the block net 610 is connected to the foundation piles 200 and the outer pipe 311, and the grouting pipe 620 and the grouting branch pipe 630 are installed, and then the inner pipe 31 2, and after being lowered into place, the sealing ball 360 is placed below, and then clay is filled between the outer tube 311 and the inner tube 312; the disturbance tube 351 is then installed on the second steel tube 321, and then the second steel tube 321 is lowered into the inner tube 312 until the positioning ring 322 is clamped in the positioning block 323, and then the groove of the block net 610 is filled and compacted with soil and gravel, and then grouting is carried out through the grouting pipe 620 and the grouting branch pipe 630; then the cushion layer 660, the hydrophobic layer 650, the waterproof layer 640 and the foundation 100 are laid in sequence, and the foundation 100 is connected to the pile foundation; finally, the side retaining wall 500 is constructed to complete the construction of the foundation pit support structure.

[0085] The water pressure of the aquifer 700 is divided through the infiltration pipe 314 and the first steel pipe 315, and when the water level rises too high, drainage is carried out in time to reduce the upward infiltration of water, thereby maintaining the stability of the foundation 100 and reducing the infiltration damage of water to the foundation 100.

[0086] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A foundation pit support structure for civil air defense projects, characterized in that: include: A foundation (100) is laid at the bottom of the foundation pit to form a construction surface; A plurality of foundation piles (200) are provided, formed at the bottom of the foundation pit and connected to the foundation (100), and used to support the foundation (100); The seepage drainage mechanism (300) comprises a plurality of seepage drainage piles (310) arranged at the bottom of a foundation pit, wherein the plurality of seepage drainage piles (310) are arranged in a staggered manner corresponding to the plurality of foundation piles (200) and extend to the aquifer (700), the seepage drainage piles (310) penetrate the foundation (100) and form a water storage cavity, and the seepage drainage piles (310) form a seepage drainage mesh hole communicating with the water storage cavity; the lower layer of the foundation (100) is sequentially paved with a water-isolating layer (640), a hydrophobic layer (650) and a cushion layer (660); A water-stop curtain formed in the soil layer and arranged around the foundation (100); A side retaining wall (500) is arranged on the foundation (100) and is used for side protection of the foundation pit; The drainage pile (310) comprises: The outer pipe (311) is buried in the soil layer and passes through the aquifer (700) of the soil layer. The pipe section located in the aquifer (700) is a permeable pipe (314). The outer side of the permeable pipe (314) is covered with a geotextile. The inner tube (312) is inserted into the outer tube (311) and there is a gap between the inner tube (311), and clay is filled between the outer tube (311) and the inner tube (312). A water storage cavity is formed in the inner tube (312), and a mesh hole for connecting the water storage cavity and the infiltration tube (314) is provided in the pipe section located in the aquifer (700), and a filter screen (316) is attached to the mesh hole, and the filter screen (316) is elastic; A drainage component (320) is disposed in the inner tube (312) and extends to the upper layer of the foundation (100); A one-way reverse osmosis plate (313) is arranged at the bottom of the outer tube (311) and blocks the water storage cavity, so that water in the water storage cavity penetrates into the underlying soil layer; The drainage assembly (320) comprises: A second steel pipe (321) is inserted into the inner pipe (312), extends to above the one-way reverse osmosis plate (313), and one end away from the one-way reverse osmosis plate (313) is connected to a drainage pump via a hose; a positioning ring (322), disposed on the second steel pipe (321) and slidably connected to the second steel pipe (321); A positioning block (323) is disposed on the second steel pipe (321) and is used to support the positioning ring (322); The second steel pipe (321) is provided with a floating component (340) and a disturbance component (350), wherein the floating component (340) comprises: A counterweight ring (341) is sleeved and slidably mounted on the second steel pipe (321), with a gap between the counterweight ring and the second steel pipe (321); A floating ball (342) is arranged on the counterweight ring (341) and is located on a side of the counterweight ring (341) close to the one-way reverse osmosis plate (313), and drives the counterweight ring (341) to move upward as the water level rises; A sensor (343) is arranged on the second steel pipe (321), and water is pumped when the counterweight ring (341) abuts against the sensor (343); Brush hairs (344) are arranged on the counterweight ring (341) and extend to the filter screen (316); The disturbance component (350) comprises: a disturbance pipe (351) which is arranged on the second steel pipe (321), extends to the position of the one-way reverse osmosis plate (313), and is connected to a disturbance pump via a hose.

2. The civil air defense project foundation pit support structure according to claim 1 is characterized in that: The hydrophobic layer (650) is arranged at an angle to collect water at the drainage pile (310).

3. The civil air defense engineering foundation pit support structure according to claim 2 is characterized in that: A block net (610) is provided between the foundation pile (200) and the drainage pile (310).

4. The civil air defense project foundation pit support structure according to claim 2 is characterized in that: A plurality of grouting pipes (620) are arranged on the foundation pile (200), and the grouting pipes (620) are arranged along the length direction of the foundation pile (200).

5. The civil air defense project foundation pit support structure according to claim 3 is characterized in that: A grouting branch pipe (630) is spirally wound on the segmented net (610) in a direction away from the foundation (100), and a plurality of grouting holes are provided on the grouting branch pipe (630).

6. The civil air defense engineering foundation pit support structure according to claim 1 is characterized in that: The pipe section of the inner pipe (312) located in the aquifer (700) is a first steel pipe (315), and a support assembly (330) is arranged outside the first steel pipe (315). The support assembly (330) comprises: At least three vertical ribs (331) are provided, parallel to the axis of the inner tube (312), and arranged at intervals along the circumference of the inner tube (312), abutting against the permeation tube (314) and supporting the permeation tube (314); A plurality of annular ribs (332) are provided, connected to the vertical ribs (331) and abutting against the permeation tube (314).

7. A construction method for a foundation pit support structure for a civil air defense project according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Excavation of foundation pit, geological survey, and excavation of foundation pit according to the geological survey results; S2, pile foundation construction, construction of water-stop curtain, excavation of foundation pile (200) holes, steel bar layout, formwork erection, and pouring construction; S3, seepage drainage construction, excavation of holes for seepage drainage piles (310), lowering the outer pipe (311) of the seepage drainage pile (310) to pass through the aquifer (700), then installing the inner pipe (312), filling the gap between the inner pipe (312) and the outer pipe (311), and then installing the drainage assembly (320); S4, grouting, installing the block net (610) and performing grouting; S5, construction of the foundation (100), laying a cushion layer (660), a hydrophobic layer (650), a waterproof layer (640) and a foundation (100) on the upper layer of the ground in sequence; S6, side retaining wall construction: formwork support is carried out on the outer edge of the foundation pit on the surface of the foundation (100), and the side retaining wall (500) is cast and formed.

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