CN111287205A - Deep multi-stage dynamic foundation pit dewatering system and dewatering method thereof - Google Patents
Deep multi-stage dynamic foundation pit dewatering system and dewatering method thereof Download PDFInfo
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- CN111287205A CN111287205A CN202010202240.5A CN202010202240A CN111287205A CN 111287205 A CN111287205 A CN 111287205A CN 202010202240 A CN202010202240 A CN 202010202240A CN 111287205 A CN111287205 A CN 111287205A
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- E02D19/00—Keeping dry foundation sites or other areas in the ground
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- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
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Abstract
The invention discloses a deep multi-stage dynamic foundation pit dewatering system and a dewatering method thereof, which relate to the technical field of civil construction, and have the technical scheme that: the system comprises a foundation pit with steps, a sedimentation tank, a booster pump, an annular main drainage pipe, a main water delivery pipe, a downcast pipe well, a light well point, a well point pump, an annular branch drainage pipe, a water tank and a drainage pipe well; the dewatering pipe well is connected with the annular drainage main pipe through a first branch pipe to form a primary pipe well dewatering system; the water tank is connected with the annular main drainage pipe through a second branch pipe to form a second-stage light well point dewatering system; the drain pipe well and the booster pump form a three-level pipe well drain system. The dewatering system is an open deep multistage dewatering mode consisting of a primary dewatering system and a secondary dewatering system, can reduce the pumping lift of a pipe well, greatly improves the drainage flow, is combined with a three-stage pipe well drainage system, improves the drainage efficiency and ensures the waterless operation of a foundation pit; the drainage and drainage system has less interference to engineering construction, low engineering cost and strong applicability.
Description
Technical Field
The invention relates to the technical field of civil construction, in particular to a deep multi-stage dynamic foundation pit dewatering system and a dewatering method thereof.
Background
With the acceleration of the urbanization process in China, the development and utilization of underground space become one of the important strategies for social development, and more foundation pit projects are inevitably generated. With the increasing requirements of engineering construction, the foundation pit continuously develops towards the direction of 'deep and near', and whether the reasonable treatment of underground water is directly related to the integral stability of the foundation pit structure and the safety of the surrounding environment. The selection of the foundation pit precipitation scheme is comprehensively determined according to engineering geology, hydrogeology, environmental factors and the like. In order to ensure that the problems of water seepage, sand gushing, pit bottom uplift and the like do not occur in the foundation pit construction process, ensure the safety of foundation pit engineering construction and the surrounding environment under the complex environment, practice the development idea of green and environment-friendly construction of underground engineering, and have higher and higher requirements on the foundation pit dewatering and drainage technology.
At present, the general foundation pit precipitation prevention mode is that water-stop curtains such as deep mixing piles, three-axis deep mixing piles, jet grouting piles and the like are constructed on the periphery, and a pipe well or light well point precipitation is arranged inside the water-stop curtains. The waterproof pile waterproof curtain often can produce the overlap joint not in place, overlap joint length scheduling problem inadequately in the construction, leads to the local of waterproof curtain to take place the infiltration, gush sand scheduling problem under the flood head effect of confined water, handles the degree of difficulty big, even mend the stake and also can cause the time limit for a project delay, increases engineering cost, also can cause great influence to foundation ditch structure and all ring edge borders safety. The invention aims to provide a deep multi-stage dynamic and open type foundation pit dewatering system to effectively overcome the defects.
Disclosure of Invention
The invention aims to provide a deep multistage dynamic foundation pit dewatering system and a dewatering method thereof. The drainage and drainage system of the foundation pit dewatering system has less interference to engineering construction, low engineering cost and stronger applicability.
The technical purpose of the invention is realized by the following technical scheme: a deep multistage dynamic foundation pit dewatering system comprises a foundation pit, wherein the foundation pit is provided with steps, and a plurality of dewatering pipe wells are arranged at the positions of slope feet of the foundation pit at equal intervals; the top surface of the step is provided with a booster pump, a water delivery main pipe and an annular drainage main pipe, and the water delivery main pipe and the annular drainage main pipe are connected with the booster pump; the downcomer well is connected with the annular main drainage pipe through a first branch pipe; a sedimentation tank is arranged on the top surface of the foundation pit, and the water outlet end of the water delivery main pipe is connected with the sedimentation tank; a plurality of light well points are annularly arranged at the bottom of the foundation pit at equal intervals; a well point pump and an annular drainage branch pipe connected with the well point pump are arranged at the second-stage slope foot of the foundation pit, and the light well point is connected with the annular drainage branch pipe; the water outlet end of the well point pump is connected with a water tank; the water tank is connected with the annular main drainage pipe through a second branch pipe; the middle part of the bottom of the foundation pit is provided with a plurality of dredging pipe wells, and the dredging pipe wells directly convey water to the sedimentation tank through the booster pump.
By adopting the technical scheme, the installation of the booster pump, the water delivery main pipe and the annular drainage main pipe is facilitated through the steps in the process of lowering the water in the foundation pit; a first-stage pipe well dewatering system is formed by the dewatering pipe well, the booster pump, the annular drainage main pipe and the water delivery main pipe, and the water in the dewatering pipe well is pumped into a sedimentation tank at the top of the foundation pit, so that the purpose of first-stage dewatering is achieved; a secondary well point dewatering system is formed by a plurality of light well points, annular drainage branch pipes, well point pumps and water tanks connected with an annular drainage main pipe, so that underground water in the light well points is conveniently conveyed to the water tanks through the well water pumps and conveyed to a sedimentation tank on the ground through the booster pumps and the water conveying main pipe, and the purpose of secondary dewatering is achieved; and a plurality of drain pipe wells connected with the booster pump are arranged in the middle of the bottom of the foundation pit to form a three-level pipe well drain system. The dewatering system forms an open deep multistage dewatering mode through a primary dewatering system and a secondary dewatering system, can greatly reduce the pumping lift of a pipe well, greatly improve the drainage flow, and is combined with a three-stage pipe well drainage system, so that the drainage efficiency is greatly improved, and the waterless operation of a foundation pit is ensured; the drainage and drainage system of the foundation pit dewatering system has less interference to engineering construction, low engineering cost and stronger applicability.
The invention is further configured to: a first water level monitoring device is arranged in the downcomer well; and a second water level monitoring device is arranged in the light well point.
Through adopting above-mentioned technical scheme, utilize first water level monitoring device and the second water level monitoring device that is located in the precipitation tube well and is located light-duty well point, be convenient for respectively the real-time supervision precipitation tube well and the light-duty well point in the water level change condition, be convenient for cooperate the precipitation system to realize the purpose of developments precipitation.
The invention is further configured to: the depth of the downcomer well is 0.5-1.0 m below the permeable layer and the opposite impermeable layer, and the bottom of the downcomer well is filled with coarse sand filter materials.
By adopting the technical scheme, the depth of the dewatering pipe well is 0.5-1.0 m below the relative impervious bed after penetrating through the pervious bed, so that the dewatering efficiency of the underground water of the foundation pit is conveniently ensured; the bottom of the downcomer is filled with coarse sand filter materials, so that fine granular soil at the bottom in the downcomer can be conveniently prevented from being pumped out along with the booster pump.
The invention is further configured to: the distance between the light well points is 1-2 m; the depth of the light well point is 0.5-1.0 m below the relative impermeable layer after penetrating through the permeable layer, and a filter pipe is arranged at the bottom of the light well point; the bottom of the dredging pipe well enters a relative impervious layer, and the underground water in the dredging pipe well is lower than the bottom of the foundation pit by more than 1 m.
By adopting the technical scheme, the distance between the light well points is 1-2 m, so that the efficiency of dewatering underground water at the bottom of the foundation pit is conveniently ensured; the depth of the light well point is 0.5-1 m below the relative impermeable layer after penetrating through the permeable layer, so that the flow of dewatering underground water in the light well point is conveniently ensured; through the filter tube, the fine particle soil impurities at the bottom in the light well point can be conveniently prevented from being pumped out of the light well point and blocking the well point pump.
The invention is further configured to: and a ring beam is arranged at the step.
By adopting the technical scheme, the step is convenient to support through the ring beam, and the overall stability of the foundation pit is improved.
The invention is further configured to: the power of the booster pump is not less than 7.5 kw.
Through adopting above-mentioned technical scheme, the power of booster pump is not less than 7.5kw, is convenient for guarantee the pumping efficiency of booster pump to groundwater.
A deep multi-stage dynamic foundation pit dewatering method comprises the following steps:
s1, performing site drilling investigation to determine the distribution state of soil layers and the underground water condition; then measuring and lofting, determining the excavation size and the slope rate of slope caving according to the ground elevation, the design elevation of the foundation pit and the underground water burying condition, excavating the foundation pit according to the design requirement, and setting the slope caving;
s2, excavating well point grooves at the slope foot of a foundation pit, punching holes and annularly arranging a plurality of downcomer wells with equal intervals, wherein the depth of each downcomer well is 0.5-1.0 m below a relative impervious bed after penetrating through a permeable bed, filling coarse sand filter materials at the bottom of a downcomer, and installing a first water level monitoring device in each downcomer well; then arranging a booster pump with the power not less than 7.5kw, an annular main drainage pipe connected with the booster pump and a main water delivery pipe connected with the booster pump at the step of the foundation pit, and connecting the downcomer well with the annular main drainage pipe through a first branch pipe; connecting the water outlet end of the water delivery main pipe with a sedimentation tank arranged at the top of the foundation pit;
s3, arranging light well points at intervals of 1-2 m at the bottom of the foundation pit in a surrounding manner, wherein the depth of each light well point is 0.5-1.0 m after the light well point penetrates through the water permeable layer and enters the position below the relative water impermeable layer, filling coarse sand filter materials into the bottom of each light well point, and arranging a second water level monitoring device in each light well point; a well point pump and an annular drainage branch pipe connected with the light well point are arranged at the second-stage slope foot of the foundation pit, the water outlet end of the well point pump is connected with a water tank, and the water tank is connected with an annular drainage main pipe through a second branch pipe;
s4, according to the abundant condition of underground water, arranging a plurality of dredging pipe wells in the middle of the bottom of the foundation pit, wherein the bottoms of the dredging pipe wells enter the relative impervious bed for a certain depth, and the underground water in the dredging pipe wells is lower than the bottom of the foundation pit by more than 1 m; connecting the dredging pipe well with a booster pump, so that water in the dredging pipe well is directly pumped to a sedimentation tank at the top of the foundation pit;
s5, arranging a foundation pit pumping scheme, performing trial pumping, checking the quality of each pipeline joint, and checking the water outlet conditions of the downcomer well and the light well point; and calculating the water yield according to the water level conditions monitored in real time by the second water level monitoring device in the light well point and the first water level monitoring device in the downcomer well, and dynamically adjusting the pumping scheme.
The foundation pit dewatering method can be used for pre-dewatering in the early stage of foundation pit construction, and can be used in combination with supporting structures such as soil nailing walls, row piles and anchor rods in construction, so that the construction speed is high, the construction cost is low, the foundation pit can be operated under the anhydrous condition, and the method is safe and reliable; meanwhile, the foundation pit dewatering method is particularly suitable for layered soil layers, the top and the bottom of the foundation pit are relatively impermeable layers, the soil layer with high water permeability is sandwiched between the top and the bottom of the foundation pit, and the top plate and the bottom plate bear the composite soil layer of confined water.
In conclusion, the invention has the following beneficial effects: the step is convenient for the installation of the booster pump, the water delivery main pipe and the annular drainage main pipe; a primary dewatering system is formed by the dewatering pipe well, the booster pump, the annular drainage main pipe and the water delivery main pipe, and the water in the dewatering pipe well is pumped into a sedimentation tank at the top of the foundation pit, so that the primary dewatering purpose is realized; a secondary dewatering system is formed by a plurality of light well points, annular drainage branch pipes, well point pumps and water tanks connected with an annular drainage main pipe, so that underground water in the light well points is conveniently conveyed to the water tanks through the well water pumps and conveyed to a sedimentation tank on the ground through a booster pump and a water conveying main pipe, and the purpose of secondary dewatering is achieved; according to the requirement, a plurality of drainage pipe wells connected with a booster pump are arranged in the middle of the bottom of the foundation pit to form a three-stage pipe well drainage system; the foundation pit dewatering system forms an open deep multistage dewatering mode through a primary dewatering system and a secondary dewatering system, can greatly reduce the pumping lift of a pipe well, greatly improves the drainage flow, is combined with a three-stage pipe well drainage system, greatly improves the drainage efficiency, and ensures the waterless operation of the foundation pit; the drainage and drainage system of the foundation pit dewatering system has less interference to engineering construction, low engineering cost and stronger applicability.
Drawings
FIG. 1 is a schematic sectional view of a precipitation system according to example 1 of the present invention;
FIG. 2 is a schematic plan view of a precipitation system according to embodiment 1 of the present invention;
fig. 3 is a flowchart in embodiment 2 of the present invention.
In the figure: 1. a foundation pit; 2. a step; 3. a downcomer well; 4. a booster pump; 5. a water delivery main pipe; 6. an annular main drain pipe; 7. a first branch pipe; 8. a sedimentation tank; 9. light well points; 10. A well point pump; 11. an annular drainage branch pipe; 12. a water tank; 13. a second branch pipe; 14. draining the pipe well; 15. a first water level monitoring device; 16. a second water level monitoring device; 17. filtering coarse sand; 18. a filter tube; 19. and (4) a ring beam.
Detailed Description
The present invention is described in further detail below with reference to figures 1-3.
Example 1: a deep multistage dynamic foundation pit 1 dewatering system is shown in figures 1 and 2 and comprises a foundation pit 1, wherein a step 2 is excavated in the foundation pit 1, and a plurality of dewatering pipe wells 3 are annularly arranged at equal intervals at the slope toe position of the foundation pit 1. The top surface of the step 2 is provided with a booster pump 4, a water delivery main pipe 5 and an annular drainage main pipe 6, and the water delivery main pipe 5 and the annular drainage main pipe 6 are connected with the booster pump 4. The downcomer well 3 is connected to an annular main drain 6 via a first branch pipe 7. A sedimentation tank 8 is arranged on the top surface of the foundation pit 1, and the water outlet end of the water delivery main pipe 5 is connected with the sedimentation tank 8. A plurality of light well points 9 are annularly arranged at the bottom of the foundation pit 1 at equal intervals. And a well point pump 10 and an annular drainage branch pipe 11 connected with the well point pump 10 are arranged at the second-stage slope foot of the foundation pit 1, and a light well point 9 is connected with the annular drainage branch pipe 11. The water outlet end of the well point pump 10 is connected with a water tank 12. The tank 12 is connected to the annular main drain conduit 6 by a second branch conduit 13. A plurality of drain pipe wells 14 are drilled in the middle of the bottom of the foundation pit 1, and the drain pipe wells 14 directly convey water to the sedimentation tank 8 through the booster pump 4.
In the embodiment in the market, in the process of lowering the water in the foundation pit 1, the step 2 is convenient for the installation of the booster pump 4, the water delivery main pipe 5 and the annular drainage main pipe 6. A primary pipe well dewatering system is formed by the dewatering pipe well 3, the booster pump 4, the annular drainage main pipe 6 and the water delivery main pipe 5, water in the dewatering pipe well 3 is pumped into a sedimentation tank 8 at the top of the foundation pit 1, and the purpose of primary dewatering is achieved. Through a plurality of light well points 9, annular drainage branch pipes 11, well point pumps 10 and the water tank 12 connected with the annular drainage main pipe 6, a second-level well point dewatering system is formed, so that underground water in the light well points 9 is conveniently conveyed to the water tank 12 through the well water pumps, and is conveyed to a sedimentation tank 8 on the ground through the booster pumps 4 and the water conveying main pipe 5, and the purpose of second-level dewatering is achieved. When the groundwater of foundation ditch 1 is abundant, through several dry pipe well 14 and booster pump 4 at the bottom of the pit middle part of foundation ditch 1, constitute tertiary pipe well dry system, directly carry groundwater to sedimentation tank 8 for dry the bottom of the pit of foundation ditch 1. Thus, a multi-stage and open type dewatering system of the foundation pit 1 is formed through the dynamic dewatering system of the dewatering pipe well 3 of the foundation pit 1, the dynamic dewatering system of the light well point 9 of the foundation pit 1 and the dewatering pipe well 14, and the dewatering efficiency is obviously improved. This precipitation system has constituted the deep multistage precipitation mode of open-type through one-level precipitation system and second grade precipitation system, can greatly reduced tube-well pump sending lift, greatly improves drainage flow to combine tertiary tube-well unwatering system, promote drainage efficiency greatly, guarantee the anhydrous operation of foundation ditch. The drainage and drainage system has less interference to engineering construction, low engineering cost and strong applicability.
A first water level monitoring device 15 is installed in the downcomer well 3. A second water level monitoring device 16 is arranged in the light well point 9.
In the embodiment in this market, the first water level monitoring device 15 and the second water level monitoring device 16 which are positioned in the precipitation pipe well 3 and the light well point 9 are utilized to facilitate real-time monitoring of water level variation conditions in the precipitation pipe well 3 and the light well point 9 respectively, and the purpose of dynamic precipitation is facilitated by matching with a precipitation system.
The depth of the downcomer well 3 is 0.5-1.0 m below the relative impervious bed through the pervious bed, and the bottom of the downcomer well 3 is filled with coarse sand filter material 17.
In this embodiment in the market, the degree of depth of precipitation pipe well 3 is for passing the permeable bed and getting into relative impermeable bed below 0.5 ~ 1.0m, is convenient for guarantee to carry out the efficiency of precipitation to the groundwater of foundation ditch 1. The bottom of the downcomer well 3 is filled with coarse sand filter material 17, so that the fine granular soil at the bottom in the downcomer well 3 can be prevented from being pumped out along with the booster pump 4.
The distance between the light well point 9 and the light well point 9 is 1-2 m. The depth of the light well point 9 is 0.5-1.0 m below the relative impermeable layer after penetrating through the permeable layer, and the bottom of the light well point 9 is provided with a filter pipe 18. The bottom of the drainage pipe well 14 enters a relatively impervious layer, and the underground water in the drainage pipe well 14 is lower than the bottom of the foundation pit 1 by more than 1 m.
In this embodiment in the market, the interval between light well point 9 and the light well point 9 is 1 ~ 2m, is convenient for guarantee to carry out the efficiency of precipitation to the groundwater of foundation ditch 1 bottom. The depth of the light well point 9 is 0.5-1 m below the relative impermeable layer after penetrating through the permeable layer, so that the flow of precipitation of underground water in the light well point 9 is convenient to guarantee. Through the filter tube 18, it is facilitated to prevent fine particle soil impurities at the bottom of the light well point 9 from being pumped out of the light well point 9 and clogging the well point pump 10.
A ring beam 19 is arranged at the step 2.
In the embodiment in the market, the step 2 is conveniently supported through the ring beam 19, and the overall stability of the foundation pit 1 is improved.
The booster pump 4 has a power of not less than 7.5 kw.
In the embodiment in the market, the power of the booster pump 4 is not less than 7.5kw, which is convenient for ensuring the pumping efficiency of the booster pump 4 to the groundwater.
Example 2: a deep multistage dynamic foundation pit 1 precipitation method, as shown in fig. 3, comprising the following steps:
and S1, performing site drilling investigation, and determining the distribution state of soil layers and the underground water condition. And then measuring and lofting, determining the excavation size and the slope rate of the slope according to the ground elevation, the designed elevation of the foundation pit 1 and the underground water burying condition, excavating the foundation pit 1 according to the design requirement, and setting the slope.
S2, excavating well point grooves at the slope foot of the foundation pit 1, punching holes to annularly arrange a plurality of dewatering pipe wells 3 with equal intervals, enabling the depth of each dewatering pipe well 3 to penetrate through the permeable layer and enter a position 0.5-1.0 m below the corresponding impermeable layer, filling coarse sand filter materials 17 at the bottoms of the dewatering pipes, and installing a first water level monitoring device 15 in each dewatering pipe well 3. Then, a booster pump 4 with power not less than 7.5kw, an annular main drain pipe 6 connected to the booster pump 4, and a main water supply pipe 5 connected to the booster pump 4 are provided at the step 2 of the foundation pit 1, and the downcomer well 3 is connected to the annular main drain pipe 6 through a first branch pipe 7. And connecting the water outlet end of the water delivery main pipe 5 with a sedimentation tank 8 arranged at the top of the foundation pit 1.
S3, arranging light well points 9 at intervals of 1-2 m at the bottom of the foundation pit 1 in a surrounding mode, enabling the depth of each light well point 9 to penetrate through the water permeable layer and to enter a position 0.5-1.0 m below the corresponding water impermeable layer, filling coarse sand filter materials 17 into the bottom of each light well point 9, and arranging a second water level monitoring device 16 in each light well point 9. And a well point pump 10 and an annular drainage branch pipe 11 connected with a light well point 9 are arranged at the second-stage slope foot of the foundation pit 1, the water outlet end of the well point pump 10 is connected with a water tank 12, and the water tank 12 is connected with an annular drainage main pipe 6 through a second branch pipe 13.
And S4, according to the abundant condition of underground water, arranging a plurality of dredging pipe wells 14 in the middle of the bottom of the foundation pit 1, wherein the bottoms of the dredging pipe wells 14 enter the relatively impervious bed for a certain depth, and the underground water in the dredging pipe wells 14 is lower than the bottom of the foundation pit 1 by more than 1 m. And the drain pipe well 14 is connected with a booster pump 4, so that water in the drain pipe well 14 is directly pumped to a sedimentation tank 8 at the top of the foundation pit 1.
S5, arranging a foundation pit 1 water pumping scheme, performing trial pumping, checking the quality of each pipeline joint, and checking the water outlet conditions of the downcomer well 3 and the light well point 9. And calculating the water yield according to the water level conditions monitored in real time by the second water level monitoring device 16 in the light well point 9 and the first water level monitoring device 15 in the dewatering well 3, and dynamically adjusting the pumping scheme.
The foundation pit 1 dewatering method can be used for pre-dewatering in the early stage of foundation pit 1 construction, can be used together with supporting structures such as soil nailing walls, row piles and anchor rods in construction, is high in construction speed and low in construction cost, ensures that the foundation pit 1 operates under the anhydrous condition, and is safe and reliable. Meanwhile, the foundation pit 1 dewatering method is particularly suitable for layering soil layers, the top and the bottom of the foundation pit are relatively impermeable layers, the soil layer with high water permeability is sandwiched between the top and the bottom of the foundation pit, and the top plate and the bottom plate bear the composite soil layer of confined water.
The working principle is as follows: in the process of lowering water to the foundation pit 1, the booster pump 4, the water delivery main pipe 5 and the annular drainage main pipe 6 are conveniently installed through the steps 2. A primary pipe well dewatering system is formed by the dewatering pipe well 3, the booster pump 4, the annular drainage main pipe 6 and the water delivery main pipe 5, water in the dewatering pipe well 3 is pumped into a sedimentation tank 8 at the top of the foundation pit 1, and the purpose of primary dewatering is achieved. Through a plurality of light well points 9, annular drainage branch pipes 11, well point pumps 10 and the water tank 12 connected with the annular drainage main pipe 6, a second-level well point dewatering system is formed, so that underground water in the light well points 9 is conveniently conveyed to the water tank 12 through the well water pumps, and is conveyed to a sedimentation tank 8 on the ground through the booster pumps 4 and the water conveying main pipe 5, and the purpose of second-level dewatering is achieved. According to the requirement, a plurality of dredging pipe wells 14 connected with the booster pump 4 are drilled in the middle of the bottom of the foundation pit 1 to form a three-stage pipe well dredging system. This precipitation system has constituted the deep multistage precipitation mode of open-type through one-level precipitation system and second grade precipitation system, can greatly reduced tube-well pump sending lift, greatly improves drainage flow to combine tertiary tube-well unwatering system, promote drainage efficiency greatly, guarantee foundation ditch 1 anhydrous operation. The drainage and drainage system of the foundation pit 1 dewatering system has less interference to engineering construction, low engineering cost and stronger applicability.
The present embodiment is only for explaining the present invention, and it is not limited to the present invention, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present invention.
Claims (7)
1. The utility model provides a deep multistage dynamic foundation ditch precipitation system which characterized by: the underground water-lowering pipe well structure comprises a foundation pit (1), wherein the foundation pit (1) is provided with steps (2), and a plurality of water-lowering pipe wells (3) are annularly arranged at the slope toe of the foundation pit (1) at equal intervals; the top surface of the step (2) is provided with a booster pump (4), a water delivery main pipe (5) and an annular drainage main pipe (6), and the water delivery main pipe (5) and the annular drainage main pipe (6) are connected with the booster pump (4); the downcomer well (3) is connected with an annular main drainage pipe (6) through a first branch pipe (7); a sedimentation tank (8) is arranged on the top surface of the foundation pit (1), and the water outlet end of the water delivery main pipe (5) is connected with the sedimentation tank (8); a plurality of light well points (9) are annularly arranged at the bottom of the foundation pit (1) at equal intervals; a well point pump (10) and an annular drainage branch pipe (11) connected with the well point pump (10) are arranged at the second-stage slope foot of the foundation pit (1), and the light well point (9) is connected with the annular drainage branch pipe (11); the water outlet end of the well point pump (10) is connected with a water tank (12); the water tank (12) is connected with the annular main drainage pipe (6) through a second branch pipe (13); the foundation pit is characterized in that a plurality of dredging pipe wells (14) are arranged in the middle of the bottom of the foundation pit (1), and the dredging pipe wells (14) directly convey water to the sedimentation tank (8) through the booster pump (4).
2. The deep multistage dynamic foundation pit dewatering system of claim 1, wherein: a first water level monitoring device (15) is arranged in the downcomer well (3); and a second water level monitoring device (16) is arranged in the light well point (9).
3. The deep multistage dynamic foundation pit dewatering system of claim 1, wherein: the depth of the downcomer well (3) is 0.5-1.0 m below the relative impervious bed after penetrating through the pervious bed, and a coarse sand filter material (17) is filled at the bottom of the downcomer well (3).
4. The deep multistage dynamic foundation pit dewatering system of claim 1, wherein: the distance between the light well points (9) and the light well points (9) is 1-2 m; the depth of the light well point (9) is 0.5-1.0 m below a relative impervious layer after penetrating through the pervious layer, and a filter tube (18) is arranged at the bottom of the light well point (9); the bottom of the drainage pipe well (14) enters a relative impervious layer, and the underground water in the drainage pipe well (14) is lower than the bottom of the foundation pit (1) by more than 1 m.
5. The deep multistage dynamic foundation pit dewatering system of claim 1, wherein: and a ring beam (19) is arranged at the step (2).
6. The deep multistage dynamic foundation pit dewatering system of claim 1, wherein: the power of the booster pump (4) is not less than 7.5 kw.
7. A deep multi-stage dynamic foundation pit dewatering method is characterized in that: the method comprises the following steps:
s1, performing site drilling investigation to determine the distribution state of soil layers and the underground water condition; then, measuring and lofting, determining the excavation size and the slope rate of slope caving according to the ground elevation, the designed elevation of the foundation pit (1) and the underground water burying condition, excavating the foundation pit (1) according to the design requirement, and setting the slope caving;
s2, excavating well point grooves at the slope foot of the foundation pit (1), punching holes and annularly arranging a plurality of downcomer wells (3) with equal intervals, wherein the depth of each downcomer well (3) penetrates through a permeable layer and enters a position which is 0.5-1.0 m below a relative impermeable layer, coarse sand filter materials (17) are filled at the bottoms of the downcomer wells, and a first water level monitoring device (15) is installed in each downcomer well (3); then, arranging a booster pump (4) with power not less than 7.5kw, an annular main drainage pipe (6) connected with the booster pump (4) and a main water delivery pipe connected with the booster pump (4) at the step (2) of the foundation pit (1), and connecting the downcomer well (3) with the annular main drainage pipe (6) through a first branch pipe (7); connecting the water outlet end of the water delivery main pipe with a sedimentation tank (8) arranged at the top of the foundation pit (1);
s3, arranging light well points (9) at intervals of 1-2 m at the bottom of a foundation pit (1) in a surrounding mode, enabling the depth of each light well point (9) to penetrate through a water permeable layer and enter a position 0.5-1.0 m below a relative water impermeable layer, filling coarse sand filter materials (17) into the bottom of each light well point (9), and arranging a second water level monitoring device (16) in each light well point (9); a well point pump (10) and an annular drainage branch pipe (11) connected with a light well point (9) are arranged at the second-level slope toe of the foundation pit (1), the water outlet end of the well point pump (10) is connected with a water tank (12), and the water tank (12) is connected with an annular drainage main pipe (6) through a second branch pipe (13);
s4, according to the abundant underground water, arranging a plurality of dredging pipe wells (14) connected with a booster pump (4) in the middle of the bottom of the foundation pit (1), and enabling the dredging pipe wells (14) to enter a relatively impervious layer, so that the underground water in the dredging pipe wells (14) is lower than the bottom of the foundation pit (1) by more than 1 m; connecting the drain pipe well (14) with a booster pump (4) to directly pump water in the drain pipe well (14) to a sedimentation tank (8);
s5, arranging a foundation pit (1) water pumping scheme, performing trial pumping, checking the quality of each pipeline joint, and checking the water outlet conditions of the downcomer well (3) and the light well point (9); according to the water level conditions monitored in real time by the second water level monitoring device (16) in the light well point (9) and the first water level monitoring device (15) in the downcomer well (3), the water yield is calculated, and the pumping scheme is dynamically adjusted.
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
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CN112746625A (en) * | 2021-01-16 | 2021-05-04 | 张荣金 | Foundation pit dewatering water level control system |
CN114250801A (en) * | 2021-12-31 | 2022-03-29 | 中交一公局第七工程有限公司 | Pipe well and light well point combined dewatering construction method |
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
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CN112746625A (en) * | 2021-01-16 | 2021-05-04 | 张荣金 | Foundation pit dewatering water level control system |
CN114250801A (en) * | 2021-12-31 | 2022-03-29 | 中交一公局第七工程有限公司 | Pipe well and light well point combined dewatering construction method |
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