An underground foundation drainage, pressure reduction, and anti-buoyancy structure and its construction method

Abstract

An underground foundation drainage, pressure reduction, and anti-buoyancy structure is disclosed. The structure is a layered structure, including a foundation pit, an original soil layer, and a backfill soil layer. A water-stop curtain is installed on one side of the original soil layer to intercept groundwater. The original soil layer is on one side of the water-stop curtain, and a vertical shaft is installed on the other side of the water-stop curtain. Multiple shafts are evenly distributed along the edge of the foundation pit. Drainage pipes are connected to the top of each shaft, and permeable blind pipes are connected to the bottom of each shaft. The permeable blind pipes are located inside the foundation pit and consist of multiple layers. Drainage holes are provided on the inner surface of each shaft. A water-stop curtain is installed around the perimeter of the foundation pit to block external water sources and effectively reduce the pressure from groundwater. Multiple layers of permeable blind pipes efficiently collect groundwater from the basement and deliver the water to the shafts through the permeable blind pipes, preventing groundwater accumulation in the lower part of the basement. The disclosure also includes a construction method for the underground foundation drainage, pressure reduction, and anti-buoyancy structure.

Description

Technical Field

[0001] This invention belongs to the field of foundation construction in building engineering, specifically relating to an underground foundation drainage, pressure reduction, and anti-buoyancy structure and its construction method. Background Technology

[0002] With the continuous development of the construction market, the number of buildings with deep foundations is also increasing. In order to effectively solve the impact of groundwater on buildings, people have invented a variety of construction methods. Among them, people often use a construction method that combines anti-buoyancy piles, anti-buoyancy anchors and waterproof membranes to solve the problems of anti-buoyancy and waterproofing. However, the installation of anti-buoyancy piles and anti-buoyancy anchors are all passive anti-buoyancy measures, which are prone to failure. In recent years, people have begun to use the drainage and depressurization method for anti-buoyancy. The traditional drainage and depressurization method requires the installation of a filter layer on the outside of the basement floor slab and side walls, and the pre-embedding of drainage pipes. The drainage pipes and filter layer work together to transport the groundwater around the underground structure to the drainage pipes inside the building, preventing the groundwater from accumulating and causing the underground structure to float.

[0003] However, after long-term use, the pre-buried drainage pipes are in direct contact with the soil layer and are prone to blockage. At the same time, the use of indoor drainage pipes during drainage increases the burden on the indoor drainage pipes. In extreme weather events such as heavy rain, the drainage pipes may be overloaded, causing groundwater to be unable to be discharged in time and resulting in a floating accident. Summary of the Invention

[0004] To address the problems of conventional drainage and depressurization anti-buoyancy structures where pre-embedded pipes are prone to clogging and where sharing drainage pipes with indoor drainage systems leads to the inability to promptly drain groundwater during heavy rainfall in extreme weather, resulting in basement buoyancy accidents, this invention proposes an underground foundation drainage and depressurization anti-buoyancy structure to solve the aforementioned problems.

[0005] An underground foundation drainage, pressure reduction, and anti-buoyancy structure is disclosed. The structure is a layered structure, comprising a foundation pit, an original soil layer, and a backfill soil layer. A water-stop curtain is installed on one side of the original soil layer to intercept groundwater. The original soil layer is on one side of the water-stop curtain, and a vertical shaft is installed on the other side of the water-stop curtain. The vertical shaft is equipped with a water pump. There are multiple vertical shafts, which are evenly distributed along the edge of the foundation pit. Backfill soil layers are installed between the vertical shafts. Drainage pipes are connected to the tops of the multiple vertical shafts, and permeable blind pipes are connected to the bottoms of the vertical shafts. The permeable blind pipes are located inside the foundation pit and consist of multiple layers. Backfill gravel layers are installed between the multiple layers of permeable blind pipes. The bottom of the lowest permeable blind pipe layer is the ground layer.

[0006] The inner surface of the shaft is provided with drainage holes, and there are multiple drainage holes evenly distributed on the inner wall of the shaft. Drainage pipes are installed on the drainage holes. One end of the drainage pipe extends into the shaft and the other end extends into the backfilled crushed stone layer. A reverse filter screen is provided at the end of the drainage pipe extending into the backfilled crushed stone layer, and water guide holes are opened on the surface of the end of the drainage pipe extending into the backfilled crushed stone layer.

[0007] A water-stop curtain is set up around the foundation pit to block external water sources, effectively reduce the pressure brought by groundwater, and prevent large amounts of precipitation from being brought by extreme weather such as rainstorms. If a large amount of rainwater flows in, the anti-buoyancy facilities will be overloaded and groundwater cannot be discharged in time, resulting in the basement floating accident.

[0008] Multiple permeable blind pipes are installed below the basement floor to efficiently collect groundwater. The water is then sent to a vertical shaft through the permeable blind pipes to prevent groundwater from accumulating in the lower part of the basement. Furthermore, the inner wall of the vertical shaft is equipped with multiple drainage holes and matching drainage pipes. The drainage pipes extend into the backfill sand and gravel layer to collect groundwater, further reducing the residual groundwater in the basement. At the same time, the drainage pipes are also wrapped with reverse filter screens to intercept silt and prevent large pieces of silt from entering the vertical shaft. The collected groundwater is stored in the vertical shaft and then pumped up to the drainage pipes, which discharge it into the recharge sand well or municipal drainage network, thus preventing the basement from floating due to groundwater accumulation.

[0009] A construction method for an underground foundation drainage, pressure reduction, and anti-buoyancy structure includes the following steps:

[0010] S1. Water-stop curtain: Before the foundation excavation, a water-stop curtain is installed around the foundation to surround it.

[0011] S2. Excavation of blind drains and shafts: Earthwork excavation and support are carried out. After the support is completed, the blind drains and shafts are excavated.

[0012] S3. Install permeable blind pipes: After the blind ditch is excavated, clean the blind ditch and install the bottom layer of permeable blind pipes. Before installation, lay a permeable blind pipe bedding layer. After the permeable blind pipe bedding layer is completed, lay a crushed stone layer with a thickness of 15cm. After laying the crushed stone layer, install the permeable blind pipes on top of the crushed stone layer. After installation, backfill with crushed stone with a thickness of 15cm. Install permeable blind pipes on top of the crushed stone layer. After installation, backfill with crushed stone. Repeat the steps to complete the installation of multiple layers of permeable blind pipes until the crushed stone is backfilled to the foundation excavation elevation.

[0013] S4. Shaft foundation construction: Foundation construction begins after the crushed stone backfilling is completed. Shaft foundation construction is carried out simultaneously during foundation construction. The shaft is connected to the permeable blind pipe. Drainage holes are set on the shaft wall, and drainage pipes are installed on the drainage holes. Repeat S3-S4 to complete the installation and connection of all permeable blind pipes and shafts, and then backfill the earthwork.

[0014] S5. Construction of drainage ditches and recharge wells: Drainage ditches and recharge wells shall be constructed when the earthwork is backfilled to the elevation of the basement roof slab. After the construction is completed, drainage pipes shall be installed in the drainage ditches.

[0015] S6. Install supporting equipment: After the building construction is completed, place the water pump in the shaft.

[0016] The design of the foundation pit takes into account the impact of blind drains on the support structure to avoid support collapse accidents.

[0017] The excavation of the blind drain requires a horizontal inclination angle of 1°-5°. When installing the permeable blind pipe, it should be installed with the middle higher and the two sides lower. The permeable blind pipe bedding layer is a concrete bedding layer, which has a certain water-stopping effect, so that the collected groundwater can flow away through the blind pipe. The blind drain set along the edge of the foundation pit is backfilled with crushed stone to the foundation excavation elevation and then backfilling is stopped. Geotextile is then laid on top to prevent soil from entering.

[0018] Furthermore, when the vertical shaft is installed, the bottom of the vertical shaft is 50cm-80cm lower than the bottom of the blind drain; this prevents the bottom of the vertical shaft from not having enough space to accommodate groundwater when it flows out, causing the groundwater to flow back into the permeable blind pipe and seep into the ground.

[0019] Furthermore, the blind drain is provided in multiple layers, and the permeable blind pipes on both sides of the blind drain located at the bottom of the foundation pit can be constructed together with the foundation. The multi-layer blind drain and the blind pipes installed in the blind drain increase the water absorption efficiency, further reduce the accumulation of groundwater, prevent the occurrence of floating accidents, and enhance the resistance and buffering capacity against heavy rainfall brought by extreme weather.

[0020] Furthermore, the drainage outlet of the drainage pipe is connected to a recharge sand well or a municipal drainage pipe. The recharge sand well needs to be set outside the water-stop curtain. The design spacing of the recharge sand wells is at least 15m-20m, and the specific design spacing is calculated according to the specific situation. The recharge sand well and the original soil layer are backfilled with sand and gravel to form a backfill sand and gravel layer. Connecting the recharge sand well or the municipal pipe network allows the discharged groundwater to be discharged quickly, avoiding affecting subsequent drainage.

[0021] Furthermore, the drainage pipe is a 50mm diameter PVC pipe. One end of the drainage pipe extends 100mm into the vertical shaft, and the other end extends 300mm into the backfilled crushed stone layer. The end extending into the backfilled crushed stone layer is wrapped with a 90mm diameter cylindrical reverse filter mesh. The drainage pipe is arranged at an angle. The drainage pipe enhances the drainage capacity of the vertical shaft, which is set around the foundation pit. While collecting groundwater in the lower part of the basement, it also intercepts and collects surface seepage water, further reducing the impact of rainfall on the groundwater drainage structure. Furthermore, the angled arrangement of the drainage pipe allows the collected rainwater or groundwater to flow into the vertical shaft under gravity, further preventing the accumulation of silt and sand that could clog the pipe.

[0022] The power source for the water pump can be set according to local conditions, and can be selected from external power supply, wind power generation or solar power generation; it has a wider range of applications. The water pump extracts groundwater and rainwater collected in the vertical shaft and sends it to the drainage pipe to prevent backflow.

[0023] Compared with the prior art, the present invention has the following technical effects:

[0024] A water-stop curtain is set up around the foundation pit to block external water sources, effectively reduce the pressure brought by groundwater, and prevent heavy rain and other extreme weather from causing a large amount of precipitation and rainwater to rush in and cause the anti-buoyancy facilities to operate under overload.

[0025] A multi-layered permeable blind pipe system is installed below the basement floor to efficiently collect groundwater. The water is then transported to a vertical shaft through the permeable blind pipes to prevent groundwater accumulation in the lower part of the basement. The inner wall of the shaft is equipped with multiple drainage holes and matching drainage pipes. The drainage pipes extend into the backfill sand and gravel layer to collect groundwater, further reducing the amount of residual groundwater in the basement. At the same time, the drainage pipes are also wrapped with a reverse filter screen to intercept silt and prevent large pieces of silt from entering the vertical shaft and causing blockages. The collected groundwater is temporarily stored in the vertical shaft and then pumped up to the drainage pipes, from where it is discharged into the recharge sand well or municipal drainage network, preventing groundwater accumulation that could cause the basement to float. The drainage structure is separated from the indoor drainage structure, reducing the burden on indoor drainage and preventing groundwater from overflowing into the room and corroding indoor facilities.

[0026] It can also withstand extreme situations. In extreme situations, when there is a lot of rainfall, the water pump may not work properly, causing the water level in the shaft to rise continuously. However, the upper part of the shaft is connected to a drainage pipe, and the drainage outlet of the drainage pipe is connected to the municipal pipe network. When the rising water level reaches the drainage pipe, it enters the municipal drainage pipe network directly through the drainage outlet, thus avoiding the accident of floating. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a plan view of the underground foundation's drainage, pressure reduction, and anti-buoyancy structure.

[0029] Figure 2 This is a cross-sectional view (AA).

[0030] Figure 3 This is a cross-sectional view of BB.

[0031] Figure 4 It is a CC cross-sectional view;

[0032] Figure 5 This is an enlarged view of part A;

[0033] Figure 6 This is an EE cross-sectional view;

[0034] Figure 7 Create a DD cross-sectional view.

[0035] In the diagram: 1. Building, 2. Foundation pit, 3. Concrete cushion layer, 4. Shaft, 5. Water-stop curtain, 6. Drainage ditch, 7. Drainage pipe, 8. Drainage outlet, 9. Geotextile, 10. Backfill gravel layer, 11. Permeable blind pipe, 12. Subgrade, 13. Backfill sand and gravel layer, 14. Original soil layer, 15. Basement, 16. Drainage hole, 1601. Concrete well wall, 1602. Drainage pipe, 1603. Reverse filter mesh, 1604. Water guide hole, 17. Water pump, 18. Ground, 19. Backfill soil layer, 20. Drainage ditch. Detailed Implementation

[0036] Example 1

[0037] like Figure 1-7 As shown; an underground foundation drainage, pressure reduction, and anti-buoyancy structure, the structure is a layered structure, including: a foundation pit 2, an original soil layer 14, and a backfill soil layer 19. A water-stop curtain 5 is provided on one side of the original soil layer 14, and the original soil layer 14 is on one side of the water-stop curtain 5. A vertical shaft 4 is provided on the other side of the water-stop curtain 5. The vertical shaft 4 is equipped with a water pump 17. There are multiple vertical shafts 4, which are evenly distributed along the edge of the foundation pit 2 and distributed underground on both sides of the building 1. A permeable blind pipe 11 is provided between the underground parts of the building 1.

[0038] A backfill soil layer 14 is provided between the vertical shafts 4. A drainage pipe 7 is connected to the top of the multiple vertical shafts 4. A permeable blind pipe 11 is connected to the bottom of the vertical shafts 4. The permeable blind pipe 11 is located inside the foundation pit 2. The permeable blind pipe includes multiple layers. A backfill crushed stone layer 10 is provided between the multiple layers of permeable blind pipes 11. The bottom of the lowest permeable blind pipe 11 is the ground layer 12. Permeable blind pipes 11 are also provided at the edge of the foundation pit 2.

[0039] The inner surface of the vertical shaft 4 is provided with drainage holes 16, and there are multiple drainage holes 16 evenly distributed along the inner surface of the vertical shaft 4. Drainage pipes 1602 are installed on the drainage holes 16. One end of the drainage pipe 1602 extends into the interior of the vertical shaft 4, and the other end of the drainage pipe 1602 extends into the backfill gravel layer 10. A reverse filter screen 1603 is provided at the end of the drainage pipe 1602 extending into the backfill gravel layer 10, and a water guide hole 1604 is opened on the surface of the end of the drainage pipe 1602 extending into the backfill gravel layer 10.

[0040] Example 2

[0041] like Figure 1-7 As shown; S1, Water-stop curtain 5: Before the foundation excavation; Install water-stop curtain 5 around the foundation to surround the foundation;

[0042] S2. Excavation of blind drain and shaft 4: Excavate the earthwork and provide support. After the support is completed, excavate the blind drain and shaft 4. The design of the foundation pit should take into account the impact of the blind drain on the support structure. The excavation of the blind drain should be set with a horizontal inclination angle of 1°-5°.

[0043] S3. Installation of Permeable Drainage Pipes 11: After the blind ditch excavation is completed, the blind ditch is cleaned, and the bottom layer of permeable drainage pipes 11 is installed. Before installation, a permeable drainage pipe 11 bedding layer is laid. The permeable drainage pipes 11 are installed with the middle layer higher than the two sides. The permeable drainage pipe 11 bedding layer is a concrete bedding layer. The blind ditch is set along the two sides of the foundation pit. The crushed stone backfilling is stopped after reaching the foundation excavation elevation, and geotextile is laid on top. After the permeable drainage pipe 11 bedding layer is completed, a crushed stone layer is laid. The layer thickness is 15cm. After the layer is laid, a permeable blind pipe 11 is installed on top of the crushed stone layer. After the installation is completed, crushed stone is used for backfilling. The crushed stone layer thickness is 15cm. A permeable blind pipe 11 is installed on the crushed stone layer. After the installation is completed, crushed stone is used for backfilling. The steps are repeated to complete the installation of multiple layers of permeable blind pipes 11 until the crushed stone is backfilled to the foundation excavation elevation. The blind ditch is set with multiple layers. The permeable blind pipes 11 on both sides of the blind ditch located at the bottom of the foundation pit 2 can be constructed together with the foundation.

[0044] S4. Shaft 4 Foundation Construction: Foundation construction begins after the crushed stone backfill is completed. Shaft 4 foundation construction is carried out simultaneously during foundation construction. When installing shaft 4, the bottom of shaft 4 is 50cm-80cm lower than the bottom of the blind drain. Shaft 4 is connected to permeable blind pipe 11. Drainage holes 16 are set on the shaft wall of shaft 4, and drainage pipes 1602 are installed on drainage holes 16. Drainage pipe 1602 is a 50mm diameter PVC pipe. One end of drainage pipe 1602 extends 100mm into the shaft 4, and the other end extends 300mm into the backfilled crushed stone layer 10. The end extending into the backfilled crushed stone layer 10 is wrapped with a 90mm diameter cylindrical reverse filter mesh. The drainage pipe 1602 is arranged at an angle. After repeating S3-S4 to complete the installation and connection of all permeable blind pipes 11 and shaft 4, earthwork backfilling is carried out.

[0045] S5. Construction of Drainage Ditch 20 and Recharge Sand Well: When the earthwork is backfilled to the elevation of the basement top slab, the construction of drainage ditch 20 and recharge sand well shall be carried out. After the construction is completed, drainage pipe 7 shall be installed in the drainage ditch. The drainage outlet 8 of drainage pipe 7 shall be connected to the recharge sand well or municipal drainage pipe. The recharge sand well shall be set outside the water-stop curtain 5. The design spacing of the recharge sand well shall be at least 15m-20m. Sand and gravel shall be backfilled between the recharge sand well and the original soil layer 14 to form a backfill sand and gravel layer 13.

[0046] S6. Install supporting equipment: After the building construction is completed, place water pump 17 in shaft 4. The power source of water pump 17 can be set according to local conditions, such as external power supply, wind power generation or solar power generation.

[0047] Example 3

[0048] like Figure 1-7 As shown; when encountering extreme weather, a large amount of rainwater is brought down. Part of the rainwater is blocked by the water-stop curtain 5, and the other part seeps into the ground above the basement 2 and enters the ground. The rainwater that enters the ground is the same as the groundwater. Part of it flows directly into the vertical shaft 4 through the drainage pipe 1602, and the other part enters the permeable blind pipe 11 through the permeable blind pipe 11. Since the permeable blind pipe 11 is arranged with the middle high and the two sides low, the rainwater and groundwater flow into the vertical shaft under the action of gravity and are pumped into the drainage pipe by the action of the water pump 17 and discharged.

[0049] Furthermore, in the event of a malfunction of the water pump 17, the water level in the shaft 4 begins to rise, and the water flows back into the permeable blind pipe 11. Since the permeable blind pipe 11 is surrounded by geotextile 9 and concrete cushion 3, the water flow is slowed down from seeping into the ground again. As the water level continues to rise, the water flows to the drainage pipe 7, and the water flows through the drainage outlet 8 of the drainage pipe 7 into the recharge well or municipal pipe network, thus preventing water accumulation and the occurrence of a floating accident.

Claims

1. An underground foundation drainage pressure-relief anti-floating structure, characterized by: The structure is a layered structure, comprising a foundation pit (2), an original soil layer (14), and a backfill soil layer (19), one side of the original soil layer (14) is provided with a waterproof curtain (5), one side of the waterproof curtain (5) is the original soil layer (14), the other side of the waterproof curtain (5) is provided with a vertical shaft (4), the vertical shaft (4) is matched with a water pump (17), the vertical shaft (4) comprises a plurality of vertical shafts (4) which are uniformly distributed along the boundary line of the foundation pit (2), the backfill soil layer (19) is arranged between the vertical shafts (4), the plurality of vertical shafts (4) are connected with a drainage pipeline (7) at the top, the vertical shaft (4) is connected with a permeable blind pipe (11) at the bottom, the permeable blind pipe (11) is located inside the foundation pit (2), the permeable blind pipe comprises multiple layers, the backfill gravel layer (10) is arranged between the multiple permeable blind pipes (11), and the bottom of the lowermost permeable blind pipe (11) is a foundation layer (12); The inner surface of the vertical shaft (4) is provided with a drain hole (16), the drain hole (16) comprises a plurality of drain holes (16) which are uniformly distributed along the inner surface of the vertical shaft (4), the drain hole (16) is provided with a drain pipeline (1602), one end of the drain pipeline (1602) extends into the vertical shaft (4), the other end of the drain pipeline (1602) extends into the backfill gravel layer (10), the end of the drain pipeline (1602) extending into the backfill gravel layer (10) is provided with a reverse filter screen bag (1603), and the surface of the end of the drain pipeline (1602) extending into the backfill gravel layer (10) is provided with a water guide hole (1604).

2. The construction method of a subterranean foundation drainage decompression anti-floating structure according to claim 1, characterized in that, The method comprises the following steps: S1, the waterproof curtain (5) is arranged before the excavation of the foundation base; the waterproof curtain (5) is installed around the foundation base to surround the foundation base; S2, excavate the blind ditch and the vertical shaft (4); after the completion of the support, the blind ditch and the vertical shaft (4) are excavated; S3, install the permeable blind pipe (11); after the completion of the blind ditch excavation, the blind ditch is cleaned, the bottommost permeable blind pipe (11) is installed, a permeable blind pipe (11) cushion layer is laid before installation, after the completion of the permeable blind pipe (11) cushion layer construction, a gravel layer is laid, the thickness of the gravel layer is 15 cm, the permeable blind pipe (11) is installed above the gravel layer after the completion of the laying, after the completion of the installation, the gravel is backfilled, the thickness of the gravel layer is 15 cm, the permeable blind pipe (11) is installed on the gravel layer, after the completion of the installation, the gravel is backfilled, the steps are repeated to complete the installation of multiple layers of permeable blind pipes until the gravel is backfilled to the foundation excavation elevation; S4, the foundation construction of the vertical shaft (4); after the completion of the gravel backfill, the foundation construction is started, the vertical shaft (4) and the permeable blind pipe (11) are connected during the foundation construction, the drain hole (16) is arranged on the wall of the vertical shaft (4), and the drain pipeline (1602) is installed on the drain hole (16), after the completion of the installation and connection of all the permeable blind pipes (11) and the vertical shaft (4), the earthwork backfill is carried out; S5, the drain ditch (20) and recharge sand well construction: when the earthwork is backfilled to the basement top plate elevation, the drain ditch (20) and recharge sand well construction is carried out, and after the construction is completed, the drain pipe (7) is installed in the drain ditch; S6, installing the supporting equipment: after the building construction is completed, the water pump (17) is placed in the vertical shaft (4).

3. The construction method of a subterranean foundation drainage decompression anti-floating structure according to claim 2, characterized in that: The influence of the blind ditch on the supporting structure is considered in the design of the foundation pit.

4. The construction method of a subterranean foundation drainage decompression anti-floating structure according to claim 2, characterized in that: The blind ditch excavation needs to be provided with a horizontal plane inclination angle of 1°-5°, the water permeable blind pipe (11) is installed in the form of high in the middle and low on both sides, the water permeable blind pipe (11) cushion layer is a concrete cushion layer (3), the blind ditch along the foundation pit (2) is stopped backfilling after the gravel is backfilled to the foundation excavation elevation, and the geotextile is laid on the top.

5. The construction method of a subterranean foundation drainage decompression anti-floating structure according to claim 2, characterized in that: The bottom of the vertical shaft (4) is 50cm-80cm lower than the bottom of the blind ditch when the vertical shaft (4) is installed.

6. The construction method of a subterranean foundation drainage decompression anti-floating structure according to claim 2, characterized in that: The blind ditch is provided with multiple layers, the water permeable blind pipe (11) on both sides of the blind ditch at the bottom of the foundation pit (2) is constructed together with the foundation.

7. The construction method of a subterranean foundation drainage decompression anti-floating structure according to claim 2, characterized in that: The drain pipe (7) drain outlet (8) is connected with the recharge sand well or the municipal drainage pipe, the recharge sand well needs to be arranged outside the water stop curtain (5), the recharge sand well design interval is at least 15m-20m, and the recharge sand well and the original soil layer (14) are backfilled with sand and pebbles to form a backfilled sand and pebble layer (13).

8. The construction method of a subterranean foundation drainage decompression anti-floating structure according to claim 2, characterized in that: The drain pipe (1602) is a PVC pipe with a diameter of 50mm, one end of the drain pipe (1602) extends into the vertical shaft (4) by 100mm, the other end extends into the backfilled gravel layer (10) by 300mm, the end extending into the backfilled gravel layer (10) is wrapped with a cylindrical reverse filter screen with a diameter of 90mm, and the drain pipe (1602) is arranged in a whole body inclination.

9. The construction method of a subterranean foundation drainage decompression anti-floating structure according to claim 2, characterized in that: The power source of the water pump (17) can be set according to the local situation, and the external power supply, wind power or solar power is selected.

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