A kind of waterproofing and drainage construction method of building foundation pit

Abstract

The present invention discloses a waterproofing and drainage construction method for a building foundation pit, comprising the following steps: (1) measuring and laying out the lines at the designed foundation pit construction site; (2) drilling the machine in place, constructing the supporting piles, and forming a first waterproof structure; (3) constructing a protective layer on the periphery of the first waterproof structure, and forming a second waterproof structure; (4) excavating the foundation pit according to the design drawing within the scope of the first waterproof structure, and after the excavation is completed, constructing a top drainage ditch on the periphery of the top of the foundation pit, and constructing a bottom drainage ditch around the inner side of the bottom of the foundation pit; (5) constructing a second drainage well below the bottom of the foundation pit; (6) constructing a waterproof layer on the bottom and inner side of the foundation pit to complete the overall waterproofing and drainage construction. The present invention realizes the combination of waterproofing and drainage of water accumulation around the foundation pit, has a fast drainage speed, and a good waterproofing effect, ensures that there is no water accumulation and water seepage inside the foundation pit, reduces the influence of surrounding water accumulation on the stability of the foundation pit, has a strong supporting effect on the foundation pit, and improves the safety of the foundation pit as a whole.

Description

Technical Field

[0001] The invention relates to the technical field of waterproof construction of building foundation pits, and in particular to a waterproof and drainage construction method for building foundation pits. Background Art

[0002] The rapid development of urban construction has led to an increasing density of buildings. As the height of buildings continues to increase, the depth of buildings has also gradually increased. This has caused the foundation pit structure of the building foundation to be located deeper underground. For areas with shallow groundwater levels, the drainage and waterproofing issues of the foundation pit during the construction of building foundations have become increasingly prominent.

[0003] Pit drainage and waterproofing are important measures to ensure the safety of pit construction and the quality of the project. The commonly used method is open ditch drainage. In the open ditch drainage method, drainage ditches are excavated around or inside the pit to collect water into the water collection well, which is then pumped away with a water pump. Waterproofing usually takes the form of setting up internal supports and continuous walls. However, when there is too much groundwater or on rainy days, the water collection well has a large amount of water inflow, and it is difficult for the water pump to quickly drain the water from the water collection well. The waterproofing effect is also poor, resulting in rising water levels in the pit that affect the stability of the pit. This affects the use function of the building and has an extremely adverse impact on the safety of the structure. The cost of leak repair and repair is also high.

[0004] Therefore, there is an urgent need for a rapid construction method that can improve the foundation pit drainage effect and efficiency and ensure the stability of the foundation pit. Summary of the invention

[0005] In order to solve the defects in the prior art, the present invention provides a waterproofing and drainage construction method for a building foundation pit. The present invention is convenient to construct, can realize the combination of waterproofing and drainage of water accumulation around the foundation pit, has a fast drainage speed, and has a good waterproofing effect, ensuring that there is no water accumulation and water seepage inside the foundation pit, reducing the influence of surrounding water accumulation on the stability of the foundation pit, and has a strong supporting effect on the foundation pit, thereby improving the safety of the foundation pit as a whole.

[0006] To achieve the above object, the present invention provides a waterproofing and drainage construction method for a building foundation pit, comprising the following steps:

[0007] (1) Conduct surveying and positioning at the designed foundation pit construction site, including reviewing and marking the benchmark points, base axis lines and leveling points of the construction site;

[0008] (2) The drilling rig is in place, calibrated and adjusted, and support piles are constructed to form the first waterproof structure; the allowable deviation of the verticality of the drill rod of the drilling rig is 0.2-0.4%;

[0009] (3) constructing a protective layer on the periphery of the first waterproof structure to form a second waterproof structure; the protective layer is a gravel pile filled with water-solidifying material; a first drainage well is arranged at the bottom of the protective layer, and a water level and water pressure sensor and a water pump are arranged in the first drainage well;

[0010] (4) Excavate the foundation pit according to the design drawing within the scope of the first waterproof structure. After the excavation is completed, construct the top drainage ditch on the periphery of the top of the foundation pit, and construct the bottom drainage ditch around the inner side of the bottom of the foundation pit;

[0011] (5) Construct a second drainage well below the bottom of the foundation pit and install water level and water pressure sensors and a water pump in the second drainage well;

[0012] (6) Construct a waterproof layer on the bottom and inner side of the foundation pit to complete the overall drainage construction.

[0013] Preferably, in step (1), obvious signs and numbers are used for marking, and corresponding protection is provided; all pile positions in the construction site are measured and located.

[0014] In any of the above schemes, it is preferred that in step (2), the drilling rig is placed at the designed hole position, the drill rod head of the drilling rig is aligned with the center of the hole position, a horizontal correction is first performed, and then the axis of the drill rod is vertically aligned with the center of the hole position; adjacent support piles are provided with an inlay structure.

[0015] In any of the above schemes, it is preferred that in step (2), during the construction of the supporting piles, a circular pile hole is first drilled, and a prefabricated concrete pile shell is placed therein, and then a rectangular pile hole is formed by milling between adjacent circular pile holes, and then a steel cage is placed in both the circular pile hole and the rectangular pile hole, and concrete is poured to form a first waterproof structure.

[0016] In any of the above schemes, preferably, in step (3), the water-solidifying material comprises the following raw materials in parts by weight: 200-300 parts by weight of sulphoaluminate cement and 80-120 parts by weight of calcium sulfate dihydrate; after the gravel pile is bored, a steel mesh cage is sunk into the hole, and the surface of the steel mesh cage facing the first waterproof structure is evenly coated with polyurethane waterproof glue; gravel is then put into the steel mesh cage, and the water-solidifying material is evenly sprinkled into the cage during the process of putting the gravel into the cage to fill the gravel.

[0017] In any of the above schemes, it is preferred that in step (3), there are multiple water pumps, and a drainage pipe is provided in the first drainage well; the water level and water pressure sensor detects the water volume and water pressure in the first drainage well, and sends a signal to the remote control device, which turns on the number of water pumps to perform drainage operations.

[0018] In any of the above schemes, it is preferred that in step (4), the top drainage ditch is filled with a paved infiltration layer, a geogrid is laid above the paved infiltration layer to the edge of the foundation pit, an asphalt waterproof layer is laid on the geogrid, and the asphalt waterproof layer does not cover the top drainage ditch; the bottom drainage ditch is also filled with a paved infiltration layer, and a second drainage well is arranged at the bottom of the bottom drainage ditch.

[0019] In any of the above schemes, it is preferred that in step (5), there are multiple water pumps, and a drainage pipe is provided in the second drainage well; the depth of the second drainage well from the ground is less than the depth of the first drainage well from the ground, and the drainage pipes of the second drainage well and the first drainage well are connected through the main drainage pipe, and the main drainage pipe is connected to the municipal drainage pipeline.

[0020] In any of the above schemes, it is preferred that in steps (3) and (5), the water pump is connected to a drainage pipe in a drainage well; a filter membrane is provided at the water inlet of the drainage pipe, and the water pump is provided with a flow detection unit for detecting the amount of water pumped at the rated power of the water pump; when a decrease in the amount of water pumped is detected, indicating that there are more impurities in the water body pumped by the water pump, the water pump is shut down to clean the impurities, and the water can be drained again after cleaning to ensure the drainage effect; and a filter layer is provided at the bottom of the first drainage well and the second drainage well.

[0021] In any of the above schemes, preferably, in step (6), the waterproof layer includes, from inside to outside, a steel mesh, an inner concrete anti-seepage layer, a moisture-proof putty layer, an outer concrete anti-seepage layer and a waterproof coating layer.

[0022] Beneficial effects of the present invention:

[0023] 1. The present invention is convenient to construct, can realize the combination of water prevention and drainage around the foundation pit, has a fast drainage speed and good waterproof effect, ensures that there is no water accumulation and seepage inside the foundation pit, reduces the influence of surrounding water accumulation on the stability of the foundation pit, and has a strong supporting effect on the foundation pit, thereby improving the safety of the foundation pit as a whole.

[0024] 2. The construction method of the present invention fully considers the overall effect of the combination of water prevention and drainage, and the design concept is more proactive. During the drainage process, the effect of rapid drainage is achieved by setting the top drainage trough, the bottom drainage trough, the first drainage well and the second drainage well. The first drainage well is higher than the second drainage well and the two are connected, so that the water around the foundation pit can be quickly discharged and away from the foundation pit; the water pump is linked with the control of the water level and water pressure sensor and the flow detection unit to achieve intelligent and optimized drainage.

[0025] 3. In the waterproofing process, by setting supporting piles and gravel piles to form a two-layer waterproof structure, as well as the setting of a waterproof layer in the foundation pit, the support stability of the foundation pit and its internal and external waterproof performance are greatly improved. The water-solidifying material and polyurethane waterproof glue set in the gravel piles ensure the effect of progressive waterproofing and drainage. When groundwater or rainwater contacts the second waterproof structure, the water reacts with the water-solidifying material and gradually hardens. In this process, excess water will flow down into the first drainage well along the gaps in the gravel. The polyurethane waterproof glue applied prevents the water from continuing to flow to the first waterproof structure. When the water-solidifying material is completely hardened, it is consolidated into one with the gravel to block the entry of water. Such a waterproofing and drainage process achieves the effect of both blocking and dredging, avoiding the situation where the soil pressure around the foundation pit is too high and easy to be damaged due to sudden and direct waterproofing measures when the water volume is large, thereby ensuring safety. DETAILED DESCRIPTION

[0026] The technical solution of the present application will be described in detail below in conjunction with the specific implementation methods of the present application, but the following examples are only for understanding the present invention. The embodiments in the present application and the features in the embodiments can be combined with each other, and the present application can be implemented in a variety of different ways as defined and covered by the claims.

[0027] Example 1

[0028] A waterproofing and drainage construction method for a building foundation pit comprises the following steps:

[0029] (1) Conduct surveying and positioning at the designed foundation pit construction site, including reviewing and marking the benchmark points, base axis lines and leveling points of the construction site;

[0030] (2) The drilling rig is in place, calibrated and adjusted, and support piles are constructed to form the first waterproof structure; the allowable deviation of the verticality of the drill rod of the drilling rig is 0.4%;

[0031] (3) constructing a protective layer on the periphery of the first waterproof structure to form a second waterproof structure; the protective layer is a gravel pile filled with water-solidifying material; a first drainage well is arranged at the bottom of the protective layer, and a water level and water pressure sensor and a water pump are arranged in the first drainage well;

[0032] (4) Excavate the foundation pit according to the design drawing within the scope of the first waterproof structure. After the excavation is completed, construct the top drainage ditch on the periphery of the top of the foundation pit, and construct the bottom drainage ditch around the inner side of the bottom of the foundation pit;

[0033] (5) Construct a second drainage well below the bottom of the foundation pit and install water level and water pressure sensors and a water pump in the second drainage well;

[0034] (6) Construct a waterproof layer on the bottom and inner side of the foundation pit to complete the overall drainage construction.

[0035] In the step (1), the piles are clearly marked and numbered, and appropriate protection is provided; all pile positions within the construction site are measured and located.

[0036] In step (2), the drilling rig is placed at the designed hole position, the drill rod head of the drilling rig is aligned with the hole center, a horizontal correction is first performed, and then the axis of the drill rod is vertically aligned with the hole center; adjacent support piles are provided with an inlay structure.

[0037] In step (2), during the construction of the supporting piles, a circular pile hole is first drilled, and a prefabricated concrete pile shell is placed therein. A rectangular pile hole is then formed by milling between adjacent circular pile holes. After that, a steel cage is placed in both the circular pile hole and the rectangular pile hole, and concrete is poured to form a first waterproof structure.

[0038] In the step (3), the water-solidifying material comprises the following raw materials in parts by weight: 200 kg of sulphoaluminate cement and 120 kg of calcium sulfate dihydrate; after the gravel pile is bored, a steel mesh cage is sunk into the hole, and the surface of the steel mesh cage facing the first waterproof structure is evenly coated with polyurethane waterproof glue; gravel is then put into the steel mesh cage, and the water-solidifying material is evenly sprinkled into the cage during the process of putting the gravel into the cage to fill the gravel.

[0039] In step (3), there are multiple water pumps, and a drainage pipe is provided in the first drainage well; a water level and water pressure sensor detects the water volume and water pressure in the first drainage well, and sends a signal to a remote control device, which turns on a number of water pumps to perform drainage operations.

[0040] In step (4), the top drainage ditch is filled with a paved infiltration layer, a geogrid is laid above the paved infiltration layer to the edge of the foundation pit, an asphalt waterproof layer is laid on the geogrid, and the asphalt waterproof layer does not cover the top drainage ditch; the bottom drainage ditch is also filled with a paved infiltration layer, and a second drainage well is arranged at the bottom of the bottom drainage ditch.

[0041] In step (5), there are multiple water pumps, and a drainage pipe is arranged in the second drainage well; the depth of the second drainage well from the ground is less than the depth of the first drainage well from the ground, and the drainage pipes of the second drainage well and the first drainage well are connected through the main drainage pipe, and the main drainage pipe is connected to the municipal drainage pipeline.

[0042] In steps (3) and (5), the water pump is connected to a drainage pipe in a drainage well; a filter membrane is provided at the water inlet of the drainage pipe, and the water pump is provided with a flow detection unit for detecting the amount of water pumped at the rated power of the water pump; when it is detected that the amount of water pumped decreases, it indicates that there are more impurities in the water body pumped by the water pump, and the water pump is shut down to clean the impurities, and the water can be drained again after cleaning to ensure the drainage effect; a filter layer is provided at the bottom of the first drainage well and the second drainage well.

[0043] In step (6), the waterproof layer includes, from the inside to the outside, a steel mesh, an inner concrete anti-seepage layer, a moisture-proof putty layer, an outer concrete anti-seepage layer and a waterproof coating layer.

[0044] Example 2

[0045] A waterproofing and drainage construction method for a building foundation pit comprises the following steps:

[0046] (1) Conduct surveying and positioning at the designed foundation pit construction site, including reviewing and marking the benchmark points, base axis lines and leveling points of the construction site;

[0047] (2) The drilling rig is in place, calibrated and adjusted, and support piles are constructed to form the first waterproof structure; the allowable deviation of the verticality of the drill rod of the drilling rig is 0.2%;

[0048] (3) constructing a protective layer on the periphery of the first waterproof structure to form a second waterproof structure; the protective layer is a gravel pile filled with water-solidifying material; a first drainage well is arranged at the bottom of the protective layer, and a water level and water pressure sensor and a water pump are arranged in the first drainage well;

[0049] (4) Excavate the foundation pit according to the design drawing within the scope of the first waterproof structure. After the excavation is completed, construct the top drainage ditch on the periphery of the top of the foundation pit, and construct the bottom drainage ditch around the inner side of the bottom of the foundation pit;

[0050] (5) Construct a second drainage well below the bottom of the foundation pit and install water level and water pressure sensors and a water pump in the second drainage well;

[0051] (6) Construct a waterproof layer on the bottom and inner side of the foundation pit to complete the overall drainage construction.

[0052] In the step (1), the piles are clearly marked and numbered, and appropriate protection is provided; all pile positions within the construction site are measured and located.

[0053] In step (2), the drilling rig is placed at the designed hole position, the drill rod head of the drilling rig is aligned with the hole center, a horizontal correction is first performed, and then the axis of the drill rod is vertically aligned with the hole center; adjacent support piles are provided with an inlay structure.

[0054] In step (2), during the construction of the supporting piles, a circular pile hole is first drilled, and a prefabricated concrete pile shell is placed therein. A rectangular pile hole is then formed by milling between adjacent circular pile holes. After that, a steel cage is placed in both the circular pile hole and the rectangular pile hole, and concrete is poured to form a first waterproof structure.

[0055] In the step (3), the water-solidifying material comprises the following raw materials in parts by weight: 300 kg of sulphoaluminate cement and 80 kg of calcium sulfate dihydrate; after the gravel pile is bored, a steel mesh cage is sunk into the hole, and the surface of the steel mesh cage facing the first waterproof structure is evenly coated with polyurethane waterproof glue; gravel is then put into the steel mesh cage, and the water-solidifying material is evenly sprinkled into the cage during the process of putting the gravel into the cage to fill the gravel.

[0056] In step (3), there are multiple water pumps, and a drainage pipe is provided in the first drainage well; a water level and water pressure sensor detects the water volume and water pressure in the first drainage well, and sends a signal to a remote control device, which turns on a number of water pumps to perform drainage operations.

[0057] In step (4), the top drainage ditch is filled with a paved infiltration layer, a geogrid is laid above the paved infiltration layer to the edge of the foundation pit, an asphalt waterproof layer is laid on the geogrid, and the asphalt waterproof layer does not cover the top drainage ditch; the bottom drainage ditch is also filled with a paved infiltration layer, and a second drainage well is arranged at the bottom of the bottom drainage ditch.

[0058] In step (5), there are multiple water pumps, and a drainage pipe is arranged in the second drainage well; the depth of the second drainage well from the ground is less than the depth of the first drainage well from the ground, and the drainage pipes of the second drainage well and the first drainage well are connected through the main drainage pipe, and the main drainage pipe is connected to the municipal drainage pipeline.

[0059] In steps (3) and (5), the water pump is connected to a drainage pipe in a drainage well; a filter membrane is provided at the water inlet of the drainage pipe, and the water pump is provided with a flow detection unit for detecting the amount of water pumped at the rated power of the water pump; when it is detected that the amount of water pumped decreases, it indicates that there are more impurities in the water body pumped by the water pump, and the water pump is shut down to clean the impurities, and the water can be drained again after cleaning to ensure the drainage effect; a filter layer is provided at the bottom of the first drainage well and the second drainage well.

[0060] In step (6), the waterproof layer includes, from the inside to the outside, a steel mesh, an inner concrete anti-seepage layer, a moisture-proof putty layer, an outer concrete anti-seepage layer and a waterproof coating layer.

[0061] In addition, in order to further improve the technical effect of the present invention, in the step (2), the precast concrete pile shell is a fan-shaped structure with a central angle of 120 degrees, and two pieces can be symmetrically placed in each circular pile hole. The precast concrete pile shell is placed close to the hole wall of the circular pile hole to prevent the circular pile hole from collapsing when constructing a rectangular pile hole. When placed symmetrically, the two precast concrete pile shells are respectively located on both sides of the part adjacent to the rectangular pile hole.

[0062] The length of the rectangular pile hole is less than the straight-line distance between the centers of two adjacent circular pile holes and greater than the distance between the closest circumferences of the two adjacent circular pile holes. In this embodiment, the length is 1.2 m. The width is the radius of the circular pile hole, and the straight line between the centers of the two adjacent circular pile holes is used as the bisector. In this embodiment, the width is 0.8 m.

[0063] The steel cage placed in the circular pile hole is composed of multiple longitudinal main bars and two transverse steel bars at the top and bottom. The steel cage placed in the rectangular pile hole is composed of multiple longitudinal main bars and multiple layers of transverse steel bars evenly arranged above and below. The longitudinal main bars in the circular pile hole are arranged in a cylindrical shape, and the transverse steel bars at the top and bottom respectively encircle the longitudinal main bars. The longitudinal main bars in the rectangular pile hole are arranged in a rectangular shape, and the transverse steel bars extend horizontally to both sides, which can contact the longitudinal main bars of the steel cage in the adjacent circular pile holes on both sides. The end of the transverse steel bar in the rectangular pile hole is provided with a magnet, which can be fixed by magnetic attraction after contacting the longitudinal main bar in the circular pile hole, and then the concrete can be directly poured into the pile, which ensures the overall stability of the steel cage of both, reduces the tediousness and complexity of steel bar binding and fixing, and greatly improves the construction efficiency and effect.

[0064] During the process of placing the sand and gravel, water-solidifying materials are evenly sprinkled in to fill the sand and gravel. In the subsequent construction process, they can be solidified into one with the sand and gravel when they come into contact with water, omitting the compaction step when filling the sand and gravel, thereby reducing the construction time while ensuring the effect.

[0065] In this embodiment, both the circular pile and the rectangular pile are provided with steel cage and concrete, which have strong shear and bending resistance, and have good water-stopping and waterproofing effects through the embedded structure. It can effectively improve the forming speed of the supporting pile, and thus can effectively speed up the construction progress; it can prevent the hole from collapsing, and at the same time, it can also prevent the surface water of the pile hole.

[0066] Example 3

[0067] A waterproofing and drainage construction method for a building foundation pit comprises the following steps:

[0068] (1) Conduct surveying and positioning at the designed foundation pit construction site, including reviewing and marking the benchmark points, base axis lines and leveling points of the construction site;

[0069] (2) The drilling rig is in place, calibrated and adjusted, and support piles are constructed to form the first waterproof structure; the allowable deviation of the verticality of the drill rod of the drilling rig is 0.3%;

[0070] (3) constructing a protective layer on the periphery of the first waterproof structure to form a second waterproof structure; the protective layer is a gravel pile filled with water-solidifying material; a first drainage well is arranged at the bottom of the protective layer, and a water level and water pressure sensor and a water pump are arranged in the first drainage well;

[0071] (4) Excavate the foundation pit according to the design drawing within the scope of the first waterproof structure. After the excavation is completed, construct the top drainage ditch on the periphery of the top of the foundation pit, and construct the bottom drainage ditch around the inner side of the bottom of the foundation pit;

[0072] (5) Construct a second drainage well below the bottom of the foundation pit and install water level and water pressure sensors and a water pump in the second drainage well;

[0073] (6) Construct a waterproof layer on the bottom and inner side of the foundation pit to complete the overall drainage construction.

[0074] In the step (1), the piles are clearly marked and numbered, and appropriate protection is provided; all pile positions within the construction site are measured and located.

[0075] In step (2), the drilling rig is placed at the designed hole position, the drill rod head of the drilling rig is aligned with the hole center, a horizontal correction is first performed, and then the axis of the drill rod is vertically aligned with the hole center; adjacent support piles are provided with an inlay structure.

[0076] In step (2), during the construction of the supporting piles, a circular pile hole is first drilled, and a prefabricated concrete pile shell is placed therein. A rectangular pile hole is then formed by milling between adjacent circular pile holes. After that, a steel cage is placed in both the circular pile hole and the rectangular pile hole, and concrete is poured to form a first waterproof structure.

[0077] In the step (3), the water-solidifying material comprises the following raw materials in parts by weight: 280 kg of sulphoaluminate cement and 100 kg of calcium sulfate dihydrate; after the gravel pile is bored, a steel mesh cage is sunk into the hole, and the surface of the steel mesh cage facing the first waterproof structure is evenly coated with polyurethane waterproof glue; gravel is then put into the steel mesh cage, and the water-solidifying material is evenly sprinkled into the cage during the process of putting the gravel into the cage to fill the gravel.

[0078] In step (3), there are multiple water pumps, and a drainage pipe is provided in the first drainage well; a water level and water pressure sensor detects the water volume and water pressure in the first drainage well, and sends a signal to a remote control device, which turns on a number of water pumps to perform drainage operations.

[0079] In step (4), the top drainage ditch is filled with a paved infiltration layer, a geogrid is laid above the paved infiltration layer to the edge of the foundation pit, an asphalt waterproof layer is laid on the geogrid, and the asphalt waterproof layer does not cover the top drainage ditch; the bottom drainage ditch is also filled with a paved infiltration layer, and a second drainage well is arranged at the bottom of the bottom drainage ditch.

[0080] In step (5), there are multiple water pumps, and a drainage pipe is arranged in the second drainage well; the depth of the second drainage well from the ground is less than the depth of the first drainage well from the ground, and the drainage pipes of the second drainage well and the first drainage well are connected through the main drainage pipe, and the main drainage pipe is connected to the municipal drainage pipeline.

[0081] In steps (3) and (5), the water pump is connected to a drainage pipe in a drainage well; a filter membrane is provided at the water inlet of the drainage pipe, and the water pump is provided with a flow detection unit for detecting the amount of water pumped at the rated power of the water pump; when it is detected that the amount of water pumped decreases, it indicates that there are more impurities in the water body pumped by the water pump, and the water pump is shut down to clean the impurities, and the water can be drained again after cleaning to ensure the drainage effect; a filter layer is provided at the bottom of the first drainage well and the second drainage well.

[0082] In step (6), the waterproof layer includes, from the inside to the outside, a steel mesh, an inner concrete anti-seepage layer, a moisture-proof putty layer, an outer concrete anti-seepage layer and a waterproof coating layer.

[0083] The bottom drainage trough is used to support the bottom of the foundation pit slope, making the foundation pit slope more stable and less likely to become unstable. It can also collect rainwater at the bottom of the foundation pit, making it less likely for water to accumulate at the bottom of the basic slope, thereby better maintaining the stability of the foundation pit slope. The top drainage trough is used to block the water outside the foundation pit from flowing into the foundation pit, making it difficult for the gathered water to seep into the ground, and making the foundation pit slope more stable.

[0084] The water level and water pressure sensors are used to sense the water level and water pressure, making the detection more accurate. When the water level and water pressure sensors exceed the set threshold, multiple pumps are selected to pump water in a timely manner to ensure real-time dynamic and active drainage, greatly improving the drainage effect.

[0085] The protective layer uses sand and gravel piles, which can save a lot of building materials and reduce project costs. At the same time, it is beneficial to improve the uniformity, stability and project quality of foundation reinforcement, and achieve a good combination of dredging and blocking effects.

[0086] The setting of two layers of waterproof structure improves the overall lateral rigidity of the supporting structure, and enhances the ability of the supporting structure to resist bending, overturning and water and soil pressure outside the pit, thereby effectively controlling the deformation of the foundation pit. It can meet the drainage requirements in the early stage and the foundation strength requirements of the later building enclosure.

[0087] In addition, in order to further improve the technical effect of the present invention, an anchoring structure may be provided between the first waterproof structure and the second waterproof structure, an anchor rod is drilled between the two, and concrete slurry is filled in the drill hole around the anchor rod. The anchoring structure is carried out between construction steps (3) and (4).

[0088] Thereby, the overall connection strength between the two is improved, and the overall strengthening support effect of the foundation pit is achieved; when the foundation pit is faced with excessive groundwater or large amounts of water on rainy days, the path for water to continue flowing into the foundation pit along the soil around the foundation pit after breaking through the second waterproof structure can be cut off, which can further ensure the drainage effect and ensure the structural stability of the foundation pit, and comprehensively optimize the overall construction effect.

[0089] The laying method of the filter layer is as follows: after the drainage pipes placed in the first drainage well and the second drainage well are fixed, pebbles with a particle size of 2-4 cm are laid around the drainage pipes, and then a layer of geotextile nonwoven fabric is laid on it, and coarse machine-made sand with a particle size of 2-5 mm is laid on it, and then another layer of geotextile nonwoven fabric is laid on it, and fine machine-made sand with a particle size of 0.1-0.2 mm is laid on it. The laying thickness of each layer is 10 cm, and finally a cushion layer is poured on it. The filter layer ensures that soil particles are prevented from being lost during the drainage process, and improves the structural stability.

[0090] It can be seen from the above embodiments that the present invention is easy to construct, can realize the combination of water prevention and drainage around the foundation pit, has a fast drainage speed, and a good waterproof effect, thereby ensuring that there is no water accumulation and seepage inside the foundation pit, reducing the impact of surrounding water accumulation on the stability of the foundation pit, and has a strong supporting effect on the foundation pit, thereby improving the safety of the foundation pit as a whole.

[0091] The construction method of the present invention fully considers the overall effect of the combination of water prevention and drainage, and the design concept is more proactive. During the drainage process, the effect of rapid drainage is achieved by setting a top drainage trough, a bottom drainage trough, a first drainage well and a second drainage well. The first drainage well is higher than the second drainage well and the two are connected, so that the water around the foundation pit can be quickly discharged and away from the foundation pit; the water pump is linked with the control of the water level and water pressure sensor and the flow detection unit to achieve intelligent and optimized drainage.

[0092] During the waterproofing process, by setting supporting piles and gravel piles to form a two-layer waterproof structure, and setting a waterproof layer in the foundation pit, the support stability of the foundation pit and its internal and external waterproof performance are greatly improved. The water-solidifying material and polyurethane waterproof glue set in the gravel piles ensure the effect of progressive waterproofing and drainage. When groundwater or rainwater contacts the second waterproof structure, the water reacts with the water-solidifying material and gradually hardens. In this process, excess water will flow down into the first drainage well along the gaps in the gravel. The applied polyurethane waterproof glue prevents the water from continuing to flow to the first waterproof structure. When the water-solidifying material is completely hardened, it is consolidated into one with the gravel to block the entry of water. Such a waterproofing and drainage process achieves the effect of both blocking and dredging, avoiding the situation where the soil pressure around the foundation pit is too high and easy to be damaged due to sudden and direct waterproofing measures when the water volume is large, thereby ensuring safety.

[0093] The above is only a preferred embodiment of the present invention, and does not limit the present invention in other forms. Any technician familiar with the profession may use the above disclosed technical content to change or modify it into an equivalent embodiment with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention still belongs to the protection scope of the technical solution of the present invention.

Claims

1. A waterproofing and drainage construction method for a building foundation pit, characterized in that: The following steps are involved: (1) Conduct surveying and positioning at the designed foundation pit construction site, including reviewing and marking the benchmark points, base axis lines and leveling points of the construction site; (2) The drilling rig is in place and calibrated and adjusted, and the support pile construction is carried out to form the first waterproof structure; the allowable deviation of the verticality of the drill rod of the drilling rig is 0.2-0.4%; during the support pile construction, a circular pile hole is first drilled, and a prefabricated concrete pile shell is placed in it. It is a fan-shaped structure with a central angle of 120 degrees. Two prefabricated concrete pile shells are symmetrically placed close to the hole wall in each circular pile hole, located on both sides of the adjacent part of the rectangular pile hole; then, a rectangular pile hole is formed by milling between adjacent circular pile holes, and then a steel cage is placed in both the circular pile hole and the rectangular pile hole, and concrete is poured; a steel cage is placed in the circular pile hole. The steel cage placed in the rectangular pile hole is composed of multiple longitudinal main bars and two transverse steel bars at the top and bottom; the steel cage placed in the rectangular pile hole is composed of multiple longitudinal main bars and multiple layers of transverse steel bars evenly arranged above and below; the longitudinal main bars in the circular pile hole are arranged in a cylindrical shape, and the transverse steel bars at the top and bottom respectively encircle the longitudinal main bars; the longitudinal main bars in the rectangular pile hole are arranged in a rectangular shape, and the transverse steel bars extend horizontally to both sides, so as to contact the longitudinal main bars of the steel cage in the adjacent circular pile holes on both sides; the end of the transverse steel bar in the rectangular pile hole is provided with a magnet, which can be fixed with the longitudinal main bars in the circular pile hole by magnetic attraction after contacting the longitudinal main bars in the circular pile hole; (3) constructing a protective layer on the periphery of the first waterproof structure to form a second waterproof structure; the protective layer is a gravel pile filled with water-solidifying material; a first drainage well is arranged at the bottom of the protective layer, and a water level and water pressure sensor and a water pump are arranged therein; the water-solidifying material comprises the following weight parts: 200-300 parts of sulphoaluminate cement and 80-120 parts of calcium sulfate dihydrate; after the gravel pile is bored, a steel mesh cage is sunk into the hole, and the surface of the steel mesh cage facing the first waterproof structure is evenly brushed with polyurethane waterproof glue; then gravel is placed in the steel mesh cage, and during the process of placing the gravel, the water-solidifying material is evenly sprinkled to fill the gravel; (4) Excavate the foundation pit according to the design drawing within the scope of the first waterproof structure. After the excavation is completed, construct the top drainage ditch on the periphery of the top of the foundation pit, and construct the bottom drainage ditch around the inner side of the bottom of the foundation pit; (5) A second drainage well is constructed below the bottom of the foundation pit, and water level and water pressure sensors and a water pump are installed in it; an anti-filtration layer is set at the bottom of the two drainage wells. After the drainage pipes placed in the two drainage wells are fixed, pebbles are laid around the drainage pipes, and then a geotextile non-woven fabric layer, a coarse machine-made sand layer, a geotextile non-woven fabric layer and a fine machine-made sand layer are laid on them in sequence, with each layer being 10 cm thick, and finally a cushion layer is poured; (6) Construct a waterproof layer on the bottom and inner side of the foundation pit to complete the overall drainage construction.

2. The waterproofing and drainage construction method for a building foundation pit according to claim 1, characterized in that: In step (1), make clear signs and numbers when marking and take appropriate protective measures; measure and locate all pile positions within the construction site.

3. The waterproofing and drainage construction method for a building foundation pit according to claim 2, characterized in that: In step (2), the drilling rig is placed at the designed hole position, the drill rod head of the drilling rig is aligned with the hole position center, a horizontal correction is first performed, and then the drill rod axis is vertically aligned with the hole position center position; adjacent support piles are provided with an inlay structure.

4. The waterproofing and drainage construction method for a building foundation pit according to claim 2 or 3, characterized in that: In step (3), there are multiple water pumps and a drainage pipe is provided in the first drainage well; a water level and water pressure sensor detects the water volume and water pressure in the first drainage well and sends a signal to a remote control device, which turns on a number of water pumps to perform drainage operations.

5. The waterproofing and drainage construction method for a building foundation pit according to claim 4, characterized in that: In step (4), the top drainage ditch is filled with a paved infiltration layer, a geogrid is laid above the paved infiltration layer to the edge of the foundation pit, an asphalt waterproof layer is laid on the geogrid, and the asphalt waterproof layer does not cover the top drainage ditch; the bottom drainage ditch is also filled with a paved infiltration layer, and a second drainage well is arranged at the bottom of the bottom drainage ditch.

6. The waterproofing and drainage construction method for a building foundation pit according to claim 5, characterized in that: In step (5), there are multiple water pumps, and a drainage pipe is arranged in the second drainage well; the depth of the second drainage well from the ground is less than the depth of the first drainage well from the ground, and the drainage pipes of the second drainage well and the first drainage well are connected through the main drainage pipe, and the main drainage pipe is connected to the municipal drainage pipeline.

7. The waterproofing and drainage construction method for a building foundation pit according to claim 6, characterized in that: In steps (3) and (5), the water pump is connected to the drainage pipe in the drainage well; a filter membrane is provided at the water inlet of the drainage pipe, and the water pump is provided with a flow detection unit for detecting the amount of water pumped at the rated power of the water pump; when it is detected that the amount of water pumped is reduced, it indicates that there are more impurities in the water body pumped by the water pump, and the pump is shut down to clean the impurities. After cleaning, the water can be discharged again to ensure its drainage effect.

8. The waterproofing and drainage construction method for a building foundation pit according to claim 7, characterized in that: In step (6), the waterproof layer includes, from the inside to the outside, a steel mesh, an inner concrete anti-seepage layer, a moisture-proof putty layer, an outer concrete anti-seepage layer and a waterproof coating layer.