CN114197479A - Earth excavation construction method based on deep foundation pit - Google Patents
Earth excavation construction method based on deep foundation pit Download PDFInfo
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- CN114197479A CN114197479A CN202210061219.7A CN202210061219A CN114197479A CN 114197479 A CN114197479 A CN 114197479A CN 202210061219 A CN202210061219 A CN 202210061219A CN 114197479 A CN114197479 A CN 114197479A
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D17/00—Excavations; Bordering of excavations; Making embankments
- E02D17/02—Foundation pits
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D1/00—Investigation of foundation soil in situ
- E02D1/02—Investigation of foundation soil in situ before construction work
- E02D1/022—Investigation of foundation soil in situ before construction work by investigating mechanical properties of the soil
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D1/00—Investigation of foundation soil in situ
- E02D1/02—Investigation of foundation soil in situ before construction work
- E02D1/027—Investigation of foundation soil in situ before construction work by investigating properties relating to fluids in the soil, e.g. pore-water pressure, permeability
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D19/00—Keeping dry foundation sites or other areas in the ground
- E02D19/06—Restraining of underground water
- E02D19/10—Restraining of underground water by lowering level of ground water
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Abstract
The invention relates to an earthwork excavation construction method based on a deep foundation pit, which relates to the field of foundation pit excavation construction and comprises the following steps: s1, building an enclosure; s2, constructing a dewatering well and a pressurizing well; s3, earth excavation construction; s4, backfilling the dewatering well and the pressurizing well; the pressurizing air pump leads gas to the pressurizing well through the pressurizing air pipe so that the air pressure in the pressurizing well is increased to a designed value and the air pressure in the pressurizing well is increased. This application has the effect that reduces foundation ditch precipitation construction to groundwater waste.
Description
Technical Field
The invention relates to the field of foundation pit excavation construction, in particular to an earth excavation construction method based on a deep foundation pit.
Background
At present, with the increase of high-rise buildings, foundation pit engineering is more and more, and the foundation pit is dug deeper. The construction of deep basal pit engineering can produce great influence to foundation ditch all ring border to in the earthwork excavation process of deep basal pit, need carry out precipitation construction to the foundation ditch within range, reduce the influence of the groundwater of foundation ditch within range to the earthwork excavation construction of foundation ditch.
In the related technology, a dewatering well is arranged in the range of the foundation pit, the dewatering well is simply adopted to extract and discharge the underground water in the range of the foundation pit, more underground water needs to be extracted, and great waste is caused to underground water resources.
Aiming at the related technologies, the inventor thinks that the defect that the ground water resource is greatly wasted in the foundation pit dewatering construction in the related technologies exists.
Disclosure of Invention
In order to reduce the waste of underground water resources caused by foundation pit dewatering construction, the application provides an earthwork excavation construction method based on a deep foundation pit.
The application provides an earthwork excavation construction method based on a deep foundation pit, which adopts the following technical scheme:
an earth excavation construction method based on a deep foundation pit comprises the following steps:
s1, building enclosure construction: building a building enclosure on the peripheral side of the foundation pit to be excavated;
s2, construction of a dewatering well and a pressurizing well: a dewatering well and a pressurizing well are arranged in the foundation pit to be excavated, a drain pipe is led into the dewatering well, the drain pipe is connected with a water pump, a pressurizing air pipe is led into the pressurizing well, the pressurizing well is sealed, and the pressurizing air pipe is connected with a pressurizing air pump;
s3, earth excavation construction: the earthwork is excavated to the designed substrate elevation in a layered mode, a pressurizing air pump and a water pump are kept started in the earthwork excavation process, air is introduced into the pressurizing well through a pressurizing air pipe by the pressurizing air pump, so that the air pressure in the pressurizing well is increased to a designed value, and water in a dewatering well is pumped out by the water pump through a drainage pipe and is discharged out of the foundation pit;
s4, backfilling the dewatering well and the pressurizing well: and (4) closing the water pump and the air pump, removing the drain pipe, the water pump, the pressurizing air pipe and the air pump, and backfilling and sealing the dewatering well and the pressurizing well.
Through adopting above-mentioned technical scheme, the water pump passes through the drain pipe and discharges the foundation ditch within range in with the precipitation well, groundwater in the soil body of foundation ditch within range permeates the precipitation well again, groundwater of depths upwards diffuses the groundwater that the replenishment was taken out, then continue to be extracted by the water pump and discharge the foundation ditch within range, this application is through increasing the pressurized well and letting in high-pressure gas to the pressurized well in, improve the atmospheric pressure in the pressurized well, high-pressure gas in the pressurized well diffuses to the soil body of foundation ditch within range from the lateral wall of pressurized well, make the atmospheric pressure in the soil body of foundation ditch within range rise, form a decurrent pressure to groundwater within range of the foundation ditch, slow down the speed that groundwater of depth upwards diffuses, thereby reduce the amount of extraction of groundwater, it is extravagant to groundwater resources to reduce foundation ditch precipitation construction, realize the energy-concerving and environment-protective of construction.
Preferably, in step S2, the depth of the excavated dewatering well is 3-5m greater than the designed bottom of the foundation pit, and the depth of the excavated pressurized well is 3-5m greater than the designed bottom of the foundation pit.
Through adopting above-mentioned technical scheme, the drainage demand of the excavation construction of arbitrary layer earthwork in the foundation ditch can be satisfied to the degree of depth of precipitation well and pressurized well to can ensure when foundation slab is under construction, groundwater can not ooze the foundation ditch bottom.
Preferably, after the dewatering well and the pressurizing well are drilled, water guns are respectively introduced into the dewatering well and the pressurizing well, and water columns are respectively sprayed out of the water guns to wash the side wall of the dewatering well and the side wall of the pressurizing well.
By adopting the technical scheme, the side wall of the dewatering well and the side wall of the pressurizing well are washed by the water column sprayed by the water gun, the smearing layer generated in the process of digging the dewatering well and the pressurizing well is damaged, the side wall of the dewatering well and the side wall of the pressurizing well are kept to have good permeability, and the water permeation efficiency of the pressurizing well and the drainage efficiency of the dewatering well are improved.
Preferably, in step S3, the drainage pipe gradually extends to the deep part of the drainage well along with the layered excavation of the earthwork, and after each layer of earthwork is excavated, the lower end of the drainage pipe extends downward to a position 3-5m below the bottom elevation of the soil layer being excavated, so that the lower end of the drainage pipe is always kept at a position 3-5m below the bottom elevation of the soil layer being excavated.
By adopting the technical scheme, the drain pipe gradually extends downwards along with the layered excavation of earthwork, so that the water level of underground water in the foundation pit is always positioned at the position 3-5m below the bottom elevation of the soil layer being excavated, the soil layer being excavated is kept in a dry state, the drain pipe only extracts the underground water more than 3-5m below the bottom elevation of the soil layer being excavated, the extraction amount of the underground water is reduced, and the waste of the underground water is further reduced.
Preferably, in step S3, the pressurized air pipe gradually extends to the deep part of the pressurized well along with the layered excavation of the earthwork, and after each layer of earthwork is excavated, the lower end of the pressurized air pipe extends downwards to a position 2-3m below the bottom elevation of the soil layer being excavated, so that the lower end of the pressurized air pipe is always kept at a position 2-3m below the bottom elevation of the soil layer being excavated.
Through adopting above-mentioned technical scheme, keep the degree of depth the pressurization trachea the same basically with the drain pipe, the gas that the pressurization trachea let in can both permeate the soil body in the top of groundwater basically, improves the utilization ratio of the gas that lets in, avoids gas to let in the depths of the water level below of groundwater and causes partial gas to permeate the soil body of the water level below of groundwater extravagant.
Preferably, in step S4, the air pump needs to gradually decrease the pressure of the gas introduced into the pressurizing well before closing, the pressure reduction process of the gas in the pressurizing well lasts for 1-2 days, and the water pump is closed after the air pump is closed.
Through adopting above-mentioned technical scheme, atmospheric pressure in the pressurized well reduces gradually, and groundwater can slowly rise, reduces the speed that groundwater rises to reduce groundwater and rise the impact to soleplate, avoid groundwater to rise too fast and take place the condition of soleplate destruction.
Preferably, before the earthwork excavation, a plurality of monitoring points for monitoring the settlement are established outside the periphery of the foundation pit to be excavated, if the settlement or the settlement speed at a certain position is found to exceed a limit value, the earthwork excavation is immediately stopped, and the foundation pit close to the monitoring point is backfilled with earthwork until the settlement or the settlement speed is restored to the limit value; after the problem that the settlement amount or the settlement speed exceeds the limit value is solved, before earth excavation is carried out again, a pressurized well is added in the foundation pit close to the monitoring point or the air pressure introduced into the pressurized well close to the monitoring point is increased.
By adopting the technical scheme, the pressure in the pressurizing well close to the monitoring point is increased or the air pressure in the pressurizing well close to the monitoring point is increased, the downward pressure on the underground water close to the monitoring point is increased, and the condition that the settlement quantity or the settlement speed exceeds the limit value occurs again when the earth excavation is carried out again is reduced.
Preferably, the outer wall of the pressurizing air pipe is fixedly sleeved with a plurality of air bags, the air bags are sequentially arranged along the length direction of the pressurizing air pipe, the air bags are communicated with the pressurizing air pipe, and an air hole is formed in the pressurizing air pipe between every two adjacent air bags.
Through adopting above-mentioned technical scheme, the air pump lets in gaseous back to the pressurized well through the trachea, atmospheric pressure in the pressurized well risees, the gasbag is filled the inflation by high-pressure gas, paste the lateral wall of tight pressurized well, the upper portion to the pressurized well is carried out the segmentation and is sealed, and cut apart into a plurality of enclosure spaces with the upper portion of pressurized well, each enclosure space is filled to the gas that comes out from the gas pocket, the atmospheric pressure in each enclosure space is more balanced, gas permeates the soil body from the lateral wall of each enclosure space again, the pressure of gas in the soil body can keep for a long time, reduce the energy consumption of air pump.
In summary, the present application includes at least one of the following beneficial technical effects:
1. high-pressure gas in the pressurized well diffuses from the side wall of the pressurized well to the soil body in the range of the foundation pit, so that the gas pressure in the soil body in the range of the foundation pit is increased, downward pressure is formed on underground water in the range of the foundation pit, and the upward diffusion speed of the deep underground water is slowed down, so that the extraction amount of the underground water is reduced, the waste of underground water resources in precipitation construction of the foundation pit is reduced, and the energy conservation and environmental protection of the construction are realized;
2. the side wall of the dewatering well and the side wall of the pressurized well are washed by the water column sprayed by the water gun, a coating layer generated in the process of constructing the dewatering well and the pressurized well is damaged, the side wall of the dewatering well and the side wall of the pressurized well are kept to have good permeability, and the water permeability efficiency of the pressurized well and the drainage efficiency of the dewatering well are improved;
3. the fixed cover of tracheal outer wall of pressurization is equipped with a plurality of gasbags, the air pump lets in gaseous back to the pressurized well through the trachea, atmospheric pressure in the pressurized well risees, the gasbag is filled the inflation by high-pressure gas, paste the lateral wall of tight pressurized well, the upper portion to the pressurized well is carried out the segmentation and is sealed, and cut apart into a plurality of enclosure spaces with the upper portion of pressurized well, each enclosure space is filled to the gas that comes out from the gas pocket, the atmospheric pressure in each enclosure space is more balanced, gaseous from the lateral wall infiltration of each enclosure space to the soil body again, the pressure of gas in the soil body can keep for a long time, reduce the energy consumption of air pump.
Drawings
Fig. 1 is a flow chart of an earth excavation construction method based on a deep foundation pit according to an embodiment of the present application.
Fig. 2 is a construction structure diagram of an earth excavation construction method based on a deep foundation pit according to an embodiment of the present application.
Fig. 3 is a schematic cross-sectional view of a-a in fig. 2.
Fig. 4 is a schematic structural view of a pressurized air tube according to an embodiment of the present application.
Description of reference numerals: 1. a foundation pit; 2. an enclosure structure; 3. dewatering wells; 4. pressurizing the well; 5. a drain pipe; 6. pressurizing the air pipe; 7. an air bag; 8. and (4) air holes.
Detailed Description
The present application is described in further detail below with reference to figures 1-4.
The embodiment of the application discloses an earth excavation construction method based on a deep foundation pit. Referring to fig. 1, 2 and 3, an earth excavation construction method based on a deep foundation pit includes the steps of:
s1, building enclosure construction: building an enclosure structure 2 on the peripheral side of a foundation pit 1 to be excavated, wherein the enclosure structure 2 comprises supporting piles and three-axis stirring piles, the supporting piles are arranged around the foundation pit 1 in a surrounding mode, the three-axis stirring piles form a waterproof curtain on the outer side wall of the supporting piles, and the tops of the supporting piles and the waterproof curtain are flush.
S2, constructing a dewatering well 3 and a pressurizing well 4: and excavating a drainage ditch outside the range of the foundation pit 1 to be excavated and pouring concrete into the drainage ditch, wherein the distance between the drainage end of the drainage ditch and the foundation pit 1 to be excavated is not less than 10 m. A plurality of dewatering wells 3 are arranged in the range of a foundation pit 1 to be dug, the depth of each dewatering well 3 is larger than the bottom of the designed foundation pit 1 by 3-5m, then a water gun is introduced into each dewatering well 3 to wash the side wall of each dewatering well 3, the water gun can spray high-pressure water columns to damage a coating layer generated in the digging process of each dewatering well 3, the permeability of the side wall of each dewatering well 3 is kept, and the well resistance effect of each dewatering well 3 is reduced. After the washing is finished, a drain pipe 5 is led into the dewatering well 3, the upper end of the drain pipe 5 is connected with a water pumping port of the water pump, and a water outlet of the water pump is connected to a drainage ditch outside the range of the foundation pit 1 to be dug through a pipeline. A plurality of pressurized wells 4 are arranged in the range of a foundation pit 1 to be excavated, the diameter of each pressurized well 4 is half of that of each dewatering well 3, the pressurized wells 4 are small and beneficial to boosting, the dewatering wells 3 are large and beneficial to drainage, the pressurized wells 4 and the dewatering wells 3 are staggered, a plurality of dewatering wells 3 are distributed around the pressurized wells 4 in the middle, a plurality of pressurized wells 4 are distributed around the dewatering wells 3 in the middle, the depth of each pressurized well 4 is larger than the designed bottom of the foundation pit 1 by 3-5m, then a high-pressure water gun is introduced into the pressurized wells 4 to wash the side walls of the pressurized wells 4, smearing layers generated in the arranging process of the pressurized wells 4 are damaged, the permeability of the side walls of the pressurized wells 4 is kept, and gas of the pressurized wells 4 can enter soil bodies above underground water more easily. After the flushing is finished, a pressurizing air pipe 6 is introduced into the pressurizing well 4, the well mouth of the pressurizing well 4 is sealed by using the well cover, and the upper end of the pressurizing air pipe 6 is connected with a pressurizing air pump.
S3, earth excavation construction: and excavating the earthwork to the elevation at the bottom of the foundation pit 1 by adopting a layered excavation mode. In the process of earth excavation, a pressurizing air pump and a water pump are kept started, the pressurizing air pump introduces air into a pressurizing well 4 through a pressurizing air pipe 6 to enable the air pressure in the pressurizing well 4 to be increased to a design value, the design value is 1.5-2 standard atmospheric pressures, and then the power of the air pump is adjusted to enable the air pressure in the pressurizing well 4 to be maintained between 1.5-2 standard atmospheric pressures. The pump pumps the groundwater in the dewatering well 3 through the drainpipe 5 and discharges the groundwater to a drainage ditch outside the foundation pit 1.
S4, backfilling by the dewatering well 3 and the pressurizing well 4: binding reinforcing steel bars at the bottom of the foundation pit 1, building a pouring template, then pouring concrete to form a reinforced concrete foundation slab, connecting the foundation slab with the support piles, and avoiding the dewatering well 3 and the pressurizing well 4 when binding the reinforcing steel bars and pouring the concrete. After the intensity of soleplate reached the requirement, reduce gradually the atmospheric pressure to the gas that pressurized well 4 let in for pressurized well 4 steps down gradually, and pressurized well 4's step down process lasts 1-2 days, and groundwater can slowly rise, reduces the speed that groundwater rose, thereby reduces groundwater and rises the impact to soleplate, avoids groundwater to rise too fast and takes place the condition of soleplate destruction. After the air pressure in the pressurized well 4 is lower than 1.1 standard atmospheric pressure, the air pump is closed, then the water pump is closed, the dewatering well 3 and the pressurized well 4 are backfilled by adopting concrete, and the well heads of the dewatering well 3 and the pressurized well 4 are subjected to sealing and water seepage prevention treatment, so that the seepage of underground water from gaps between the backfilled dewatering well 3 and the foundation slab and gaps between the pressurized well 4 and the foundation slab is avoided.
In the process of earthwork excavation construction, the drain pipe 5 gradually extends to the deep part of the drain well along with the layered excavation of the earthwork. After each layer of earthwork is excavated, the lower end of the drainage pipe 5 extends downwards to a position 3-5m below the bottom elevation of the soil layer being excavated, the water level of the underground water is controlled to be 3-5m below the bottom elevation of the soil layer being excavated, and the soil layer being excavated is kept in a dry state. The drain pipe 5 can only extract the underground water which is obtained by the lower end of the drain pipe 5, so that the extraction amount of the underground water is reduced, the extraction amount of the underground water is further reduced, the energy is saved, and meanwhile, the waste of underground water resources is reduced.
The drainage end in escape canal is equipped with the cistern, and the cistern deposits escape canal exhaust groundwater, and the cistern is connected with the dust fall pump, and the dust fall pump is connected with atomizer, and atomizer erects in the top of foundation ditch 1. The water extraction in the dust fall pump will impoundment and through the atomizer blowout, forms water smoke through atomizer blowout water, carries out the dust fall to foundation ditch 1, and protection construction environment is clean, prevents that the earth excavation in-process raise dust is too big, causes environmental pollution.
In the process of earthwork excavation construction, the pressurizing air pipe 6 gradually extends to the deep part of the pressurizing well 4 along with the layered excavation of earthwork, after one layer of earthwork is excavated, the lower end of the pressurizing air pipe 6 downwards extends to the position 2-3m below the bottom elevation of the soil layer being excavated, and the lower end of the pressurizing air pipe 6 is higher than the lower end of the drain pipe 5, so that high-pressure gas in the pressurizing well 4 is kept above the water level of underground water, the utilization rate of the introduced gas is improved, and the waste of soil body, below the water level of the underground water, caused by the fact that part of gas permeates into the deep part below the water level of the underground water due to the fact that the gas is introduced into the deep part below the water level of the underground water is avoided.
Before earthwork excavation, a plurality of monitoring points for monitoring settlement are established outside the periphery of a foundation pit 1 to be excavated, if settlement or settlement speed at a certain position exceeds a limit value, earthwork excavation is immediately stopped, earthwork backfilling is carried out on the foundation pit 1 close to the monitoring point until the settlement or settlement speed is recovered to the limit value, then a factor that the settlement or settlement speed exceeds the limit value is found, and measures are taken to prevent the settlement or settlement speed from appearing again at the monitoring point from exceeding the limit value. After the problem that the settlement amount or the settlement speed exceeds the limit value is solved, before earthwork excavation is carried out again, the pressurizing well 4 is added in the foundation pit 1 close to the monitoring point or the air pressure introduced into the pressurizing well 4 close to the monitoring point is increased, the downward pressure on the underground water close to the monitoring point is increased, and therefore the situation that the settlement amount or the settlement speed exceeds the limit value occurs again when earthwork excavation is carried out again on the monitoring point is reduced.
Referring to fig. 4, the outer wall of the pressurized air tube 6 is fixedly sleeved with a plurality of air bags 7, the air bags 7 are made of rubber, the air bags 7 are sequentially arranged along the length direction of the pressurized air tube 6, the air bags 7 are communicated with the pressurized air tube 6, and an air hole 8 is formed between every two adjacent air bags 7 of the pressurized air tube 6. After the air pump lets in gas to pressurized well 4 through the trachea, the atmospheric pressure in pressurized well 4 rises, gasbag 7 is filled the inflation by high-pressure gas, paste the lateral wall of pressurized well 4 tightly, the upper portion of pressurized well 4 is carried out the segmentation and is sealed, and divide into a plurality of enclosure spaces with the upper portion of pressurized well 4, each enclosure space is filled to the gas that comes out from gas pocket 8, the atmospheric pressure in each enclosure space is more balanced, gas permeates into the soil body from the lateral wall of each enclosure space again, the pressure of gas in the soil body can keep for a long time, reduce the energy consumption of air pump. By setting the height of the air bag 7, the sealing spaces can be positioned at different depths, which is beneficial to controlling the position of the gas entering the soil body. When the soil layer being excavated needs to be excavated to the bottom elevation, the air pump is closed firstly, the air pressure in the pressurizing well 4 is recovered to the standard atmospheric pressure, the air bag 7 is reduced, the pressurizing air pipe 6 extends downwards to the proper position, the air pump is opened to introduce air into the pressurizing well 4, and after the air pump is closed, the power of the water pump connected with the lifting well around the pressurizing well 4 of the air pump needs to be increased, and the underground water which is accelerated to rise is discharged after the air pump is closed.
The implementation principle of the earth excavation construction method based on the deep foundation pit in the embodiment of the application is as follows: the air pump lets in high-pressure gas through the forcing pipe in to the pressurized well 4, improve the atmospheric pressure in the pressurized well 4, high-pressure gas in the pressurized well 4 permeates to the soil body of foundation ditch 1 within range from the lateral wall of pressurized well 4, make the atmospheric pressure in the soil body of foundation ditch 1 within range rise, form a decurrent pressure to the groundwater in the soil body clearance of foundation ditch 1 within range, slow down the rising speed of the groundwater of depths, thereby reduce the supplementary speed of the groundwater of shallow department, reduce the groundwater volume that needs to take out, reduce the workload of water pump and reduce foundation ditch 1 precipitation construction and waste groundwater resources, realize the energy-concerving and environment-protective of construction.
The above embodiments are preferred embodiments of the present application, and the protection scope of the present application is not limited by the above embodiments, so: all equivalent changes made according to the structure, shape and principle of the present application shall be covered by the protection scope of the present application.
Claims (8)
1. An earth excavation construction method based on a deep foundation pit is characterized by comprising the following steps:
s1, building enclosure construction: building a building enclosure (2) on the peripheral side of the foundation pit (1) to be excavated;
s2, constructing the dewatering well (3) and the pressure well (4): a dewatering well (3) and a pressurized well (4) are arranged in a foundation pit (1) to be excavated, a drain pipe (5) is introduced into the dewatering well (3), the drain pipe (5) is connected with a water pump, a pressurized air pipe (6) is introduced into the pressurized well (4), the pressurized well (4) is closed, and the pressurized air pipe (6) is connected with a pressurized air pump;
s3, earth excavation construction: the earthwork is excavated to the designed substrate elevation in a layered mode, a pressurizing air pump and a water pump are kept started in the earthwork excavation process, the pressurizing air pump introduces air into a pressurizing well (4) through a pressurizing air pipe (6) to enable the air pressure in the pressurizing well (4) to be increased to the designed value, and the water pump pumps water in a dewatering well (3) through a drainage pipe (5) and discharges the water to the outside of a foundation pit (1);
s4, backfilling the dewatering well (3) and the pressure well (4): and (3) closing the water pump and the air pump, removing the drain pipe (5), the water pump, the pressurizing air pipe (6) and the air pump, and backfilling and sealing the dewatering well (3) and the pressurizing well (4).
2. The earth excavation construction method based on the deep foundation pit as claimed in claim 1, wherein: in the step S2, the depth of the drilled dewatering well (3) is 3-5m greater than the bottom of the designed foundation pit (1), and the depth of the drilled pressurized well (4) is 3-5m greater than the designed base elevation.
3. The earth excavation construction method based on the deep foundation pit as claimed in claim 1, wherein: after the dewatering well (3) and the pressurized well (4) are drilled, water guns are respectively introduced into the dewatering well (3) and the pressurized well (4), and water columns are respectively sprayed out of the water guns to wash the side wall of the dewatering well (3) and the side wall of the pressurized well (4).
4. The earth excavation construction method based on the deep foundation pit as claimed in claim 1, wherein: in the step S3, the drain pipe (5) gradually extends to the deep part of the drain well along with the layered excavation of the earthwork, and after each layer of earthwork is excavated, the lower end of the drain pipe (5) downwards extends to the position 3-5m below the bottom elevation of the soil layer being excavated, so that the lower end of the drain pipe (5) is always kept at the position 3-5m below the bottom elevation of the soil layer being excavated.
5. The earth excavation construction method based on the deep foundation pit as claimed in claim 4, wherein: in the step S3, the pressurizing air pipe (6) gradually extends to the deep part of the pressurizing well (4) along with the layered excavation of earthwork, and after each layer of earthwork is excavated, the lower end of the pressurizing air pipe (6) downwards extends to the position 2-3m below the bottom elevation of the soil layer being excavated, so that the lower end of the pressurizing air pipe (6) is always kept at the position 2-3m below the bottom elevation of the soil layer being excavated.
6. The earth excavation construction method based on the deep foundation pit as claimed in claim 1, wherein: in step S4, the air pump needs to gradually decrease the pressure of the gas introduced into the pressure well (4) before closing, the pressure reduction process of the gas in the pressure well (4) lasts for 1-2 days, and the water pump is closed after the air pump is closed.
7. The earth excavation construction method based on the deep foundation pit as claimed in claim 1, wherein: before earth excavation, establishing a plurality of monitoring points for monitoring settlement outside the periphery of a foundation pit (1) to be excavated, stopping the earth excavation immediately if the settlement or the settlement speed at a certain position is found to exceed a limit value, and backfilling earth of the foundation pit (1) close to the monitoring point until the settlement or the settlement speed is recovered to the limit value; before earth excavation is carried out again, a pressurized well (4) is added in the foundation pit (1) close to the monitoring point or the air pressure introduced into the pressurized well (4) close to the monitoring point is improved.
8. The earth excavation construction method based on the deep foundation pit as claimed in claim 1, wherein: the outer wall of the pressurization air pipe (6) is fixedly sleeved with a plurality of air bags (7), the air bags (7) are sequentially arranged along the length direction of the pressurization air pipe (6), the air bags (7) are communicated with the pressurization air pipe (6), and an air hole (8) is formed between every two adjacent air bags (7) of the pressurization air pipe (6).
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114859016A (en) * | 2022-06-21 | 2022-08-05 | 西安理工大学 | Loess collapsibility test method |
| CN114922214A (en) * | 2022-06-21 | 2022-08-19 | 西安黄土地下工程技术咨询有限公司 | Pressure-stabilizing permeation-promoting method and pressure dewatering equipment suitable for said method |
-
2022
- 2022-01-19 CN CN202210061219.7A patent/CN114197479A/en not_active Withdrawn
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114859016A (en) * | 2022-06-21 | 2022-08-05 | 西安理工大学 | Loess collapsibility test method |
| CN114922214A (en) * | 2022-06-21 | 2022-08-19 | 西安黄土地下工程技术咨询有限公司 | Pressure-stabilizing permeation-promoting method and pressure dewatering equipment suitable for said method |
| CN114922214B (en) * | 2022-06-21 | 2024-05-17 | 西安黄土地下工程技术咨询有限公司 | Pressure stabilizing and seepage promoting method and pressurized precipitation equipment suitable for same |
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