CN111877377A - Foundation pit dewatering construction method - Google Patents
Foundation pit dewatering construction method Download PDFInfo
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- CN111877377A CN111877377A CN202010456011.6A CN202010456011A CN111877377A CN 111877377 A CN111877377 A CN 111877377A CN 202010456011 A CN202010456011 A CN 202010456011A CN 111877377 A CN111877377 A CN 111877377A
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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
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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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- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Environmental & Geological Engineering (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Mining & Mineral Resources (AREA)
- Paleontology (AREA)
- Civil Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Structural Engineering (AREA)
- Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)
Abstract
A foundation pit dewatering construction method comprises the following steps: (1) surveying and preparing; (2) designing a dewatering well; (3) connecting the periphery of the foundation pit with a wall; (4) measuring and paying off; (5) drilling to form a hole; (6) mounting a well pipe; (7) washing the well; (8) pumping water; (9) and (7) backfilling the dewatering well. According to the construction method, the structure, the position and the number of the dewatering wells in the deep foundation pit are reasonably planned according to actual construction conditions and construction requirements, the dewatering wells can accommodate underground water burst, the deep foundation pit is kept dry, and the deep foundation pit structure construction can be smoothly carried out; the water pump is used for pumping underground water burst in the dewatering well to complete dewatering operation, the operation is simple and convenient, the effect is good, the construction of a deep foundation pit structure is not influenced, the construction safety is enhanced, and the construction efficiency is improved.
Description
Technical Field
The invention relates to the field of constructional engineering, in particular to a foundation pit dewatering construction method.
Background
Along with the expansion of the development scale of urban underground space, high-rise buildings, subways and high-speed railways are rapidly developed, more and more underground facilities are continuously emerged, the area of the underground structure of a house building is continuously increased, the depth is continuously deepened, the construction excavation engineering quantity is large, oversized and ultra-deep foundation pit engineering is also increased, part of ultra-deep foundation pits can possibly appear in a water-rich sandy gravel stratum and a flowing sand bearing water soil layer, such as miscellaneous filling soil, plain filling soil, clay, silty clay, silt silty clay, two layers of silty clay, silt and three layers of silty clay from top to bottom in sequence, the stratum area is always high in strength under the action of static load, but when excavation operation is carried out, the vibration load action is generated, the sandy soil is possibly liquefied or largely collapsed and deformed, the bearing capacity is lost, and the ultra-deep foundation pits can meet underground water when being excavated, need carry out precipitation and handle, and because the loose characteristic of above-mentioned soil layer makes the silt in situ very easily take place rivers and flow from the foundation ditch extroversion to the foundation ditch in carrying out precipitation and handle, arouses the decline of the water level of the upper strata soil layer outside the foundation ditch, leads to the peripheral earth's surface of foundation ditch to subside, the collapse and the sand drift accident appear easily, and then influence work efficiency.
Disclosure of Invention
The invention aims to solve the problems and provides a precipitation construction treatment method which is safer in construction efficiency, higher in construction efficiency and suitable for deep foundation pits.
The technical scheme adopted by the invention is as follows:
a foundation pit dewatering construction method comprises the following steps:
(1) preparing for investigation: performing site investigation to find out the geological conditions and hydrological parameters of a site;
(2) designing a dewatering well: designing a dewatering well based on the geological conditions and the hydrological parameters to obtain dewatering well parameters and well bit data;
(3) the periphery of the foundation pit is connected with the wall: constructing a ground connecting wall at the periphery of the foundation pit, and sequentially penetrating geological soil layers through the ground connecting wall;
(4) and (3) measurement and paying-off: the method comprises the following steps of (1) carrying out field measurement, lofting and well positioning, and burying an opening protecting pipe at a well position;
(5) drilling to form a hole: drilling a dewatering well hole at a well position by using a drilling machine, and reinforcing the wall of the hole in the dewatering well hole drilling process;
(6) mounting a well pipe: after the well bore is lowered to the designed depth, cleaning the hole, putting the well bore into the well bore, adopting a sand-free concrete well bore, and filling a filter material between the well bore and the wall of the hole;
(7) well flushing: putting a sewage pump at the bottom of the dewatering well, injecting clear water into the dewatering well, and repeatedly pumping and washing by using the sewage pump to perform well washing operation until the water is sand-cleaned, thereby completing construction of the dewatering well;
(8) pumping water; installing a water pump and a pipeline system for pumping water; after the underground gushing water enters the precipitation well and reaches a preset height, the water pump is used for pumping the underground gushing water in the precipitation well to finish precipitation operation;
(9) backfilling a dewatering well: and after the dewatering well is used, the water pump and the pipeline system are disassembled, and backfilling and tamping are carried out.
The structure of the dewatering well comprises: the well casing comprises a precipitation well hole, a well casing and a filler, wherein the well casing is arranged in the precipitation well hole, and the filler is filled between the well casing and the precipitation well hole.
The process of forming the dewatering well by drilling construction in the step (5) and the step (6) by using a drilling machine comprises the following steps: burying a mouth protecting pipe at the actual position of each dewatering well to be constructed; the drilling machine aims at the central position of the protective pipe to carry out drilling construction to form a precipitation well hole; after the drilling is carried out to the designed well depth position, the dewatering well hole is punched by clear water to remove impurities in the dewatering well hole until mud returning from the dewatering well hole does not contain mud blocks; and (3) lowering the well pipe into the dewatering well hole, filling filler between the well pipe and the dewatering well hole, and ensuring the well pipe to be vertical to form the dewatering well.
And (5) controlling the density of the mud in the precipitation well hole within a preset range in the drilling construction process, and filling the mud in the precipitation well hole to prevent the wall of the precipitation well hole from collapsing.
And (4) filtering materials in the step (6) adopt medium-sized sand and crushed stone chips with the particle size of 6-8 mm.
And (5) pumping underground gushing water in the dewatering well by using a water pump in the step (8), and enabling the underground water level to be not less than 0.5m below the bottom of the foundation pit so as to finish dewatering operation.
The invention has the beneficial effects that: according to the construction method, the structure, the position and the number of the dewatering wells in the deep foundation pit are reasonably planned according to actual construction conditions and construction requirements, the dewatering wells can accommodate underground water burst, the deep foundation pit is kept dry, and the deep foundation pit structure construction can be smoothly carried out; the water pump is used for pumping underground water burst in the dewatering well to complete dewatering operation, the operation is simple and convenient, the effect is good, the construction of a deep foundation pit structure is not influenced, the construction safety is enhanced, and the construction efficiency is improved.
Detailed Description
A foundation pit dewatering construction method comprises the following steps:
(1) preparing for investigation: performing site investigation to find out the geological conditions and hydrological parameters of a site;
(2) designing a dewatering well: designing precipitation wells based on the geological conditions and the hydrological parameters, obtaining precipitation well parameters and well bit data, and respectively calculating and obtaining the water inflow, the single well water yield, the precipitation well quantity and the precipitation well depth on site;
(3) the periphery of the foundation pit is connected with a wall, a ground connection wall is constructed at the periphery of the foundation pit, and each geological soil layer is sequentially penetrated through the ground connection wall;
(4) and (3) measurement and paying-off: the method comprises the following steps of (1) carrying out field measurement, lofting and well positioning, and burying an opening protecting pipe at a well position;
(5) drilling to form a hole: drilling a dewatering well hole at a well position by using a drilling machine, reinforcing the wall of the well in the process of drilling the dewatering well hole, controlling the density of slurry in the dewatering well hole within a preset range in the drilling construction process, and fully pressing the slurry in the dewatering well hole to prevent the wall of the dewatering well hole from collapsing;
(6) mounting a well pipe: after the precipitation well hole to the design degree of depth, the hole is cleared, and the well pipe is gone into to the well pipe, adopts no sand concrete well casing to fill between well casing and hole wall as the filter material with coarse sand in the 6 ~ 8mm particle size, rubble bits, utilize the rig to carry out the process that the well drilling construction formed the precipitation well, include: burying a mouth protecting pipe at the actual position of each dewatering well to be constructed; the drilling machine aims at the central position of the protective pipe to carry out drilling construction to form a precipitation well hole; after the drilling is carried out to the designed well depth position, the dewatering well hole is punched by clear water to remove impurities in the dewatering well hole until mud returning from the dewatering well hole does not contain mud blocks; putting the well pipe into a precipitation well hole, filling filler between the well pipe and the precipitation well hole and ensuring the well pipe to be vertical to form a precipitation well;
(7) well flushing: putting a sewage pump at the bottom of the dewatering well, injecting clear water into the dewatering well, and repeatedly pumping and washing by using the sewage pump to perform well washing operation until the water is sand-cleaned, thereby completing construction of the dewatering well;
(8) pumping water; installing a water pump and a pipeline system for pumping water; after the underground gushing water enters the precipitation well and reaches a preset height, pumping the underground gushing water in the precipitation well by using a water pump, and enabling the underground water level to be not less than 0.5m below the bottom of the foundation pit so as to finish the precipitation operation;
(9) backfilling a dewatering well: and after the dewatering well is used, the water pump and the pipeline system are disassembled, and backfilling and tamping are carried out.
The structure of the dewatering well comprises: the well casing comprises a precipitation well hole, a well casing and a filler, wherein the well casing is arranged in the precipitation well hole, and the filler is filled between the well casing and the precipitation well hole.
Example 1
A foundation pit dewatering construction method comprises the following steps:
(1) preparing for investigation: performing on-site investigation to find out on-site geological conditions and hydrological parameters, wherein the geological layer sequentially comprises a mixed filling layer with the thickness of 0.5-2.20 m, a plain filling layer with the thickness of 0.6-2.20 m, a clay layer with the thickness of 1.10-4.80 m, a silty clay layer with the thickness of 2.00-5.20 m, a silty clay and silt silty clay layer with the thickness of 1.2-5.3 m, a second layer of silty clay layer with the thickness of 1.9-7.4 m, a silty clay layer with the thickness of 1.00-4.00 m and a third layer of silty clay layer with the thickness of 1.20-5.70 m from top to bottom; the hydrological parameter is that the buried depth of the upper layer stagnant water static water level is about 1.70-8.00 m;
(2) designing a dewatering well: designing precipitation wells based on the geological conditions and the hydrological parameters, obtaining precipitation well parameters and well bit data, and respectively calculating and obtaining the water inflow, the single well water yield, the precipitation well quantity and the precipitation well depth on site;
(3) the periphery of the foundation pit is connected with a wall, a ground connection wall is constructed at the periphery of the foundation pit, and each geological soil layer is sequentially penetrated through the ground connection wall;
(4) and (3) measurement and paying-off: the method comprises the following steps of (1) carrying out field measurement, lofting and well positioning, and burying an opening protecting pipe at a well position;
(5) drilling to form a hole: drilling a dewatering well hole at a well position by using a drilling machine, reinforcing the wall of the well in the process of drilling the dewatering well hole, controlling the density of slurry in the dewatering well hole within a preset range in the drilling construction process, and fully pressing the slurry in the dewatering well hole to prevent the wall of the dewatering well hole from collapsing;
(6) mounting a well pipe: after precipitation well bore to the design degree of depth, the hole is cleared, and the well pipe is gone into to the well, adopts no sand concrete well casing, and pipe diameter 500mm becomes well diameter 800mm to fill between well casing and bore wall as the filter material with coarse sand in the 6 ~ 8mm particle diameter, rubble bits, utilize the rig to carry out the process that the well drilling construction formed the precipitation well, include: burying a mouth protecting pipe at the actual position of each dewatering well to be constructed; the drilling machine aims at the central position of the protective pipe to carry out drilling construction to form a precipitation well hole; after the drilling is carried out to the designed well depth position, the dewatering well hole is punched by clear water to remove impurities in the dewatering well hole until mud returning from the dewatering well hole does not contain mud blocks; putting the well pipe into a precipitation well hole, filling filler between the well pipe and the precipitation well hole and ensuring the well pipe to be vertical to form a precipitation well;
(7) well flushing: putting a sewage pump at the bottom of the dewatering well, injecting clear water into the dewatering well, and repeatedly pumping and washing by using the sewage pump to perform well washing operation until the water is sand-cleaned, thereby completing construction of the dewatering well;
(8) pumping water; installing a water pump and a pipeline system for pumping water; after the underground water burst enters the dewatering well and reaches a preset height, pumping the underground water burst in the dewatering well by using a water pump, so that the underground water level is reduced to be not less than 0.5m below the bottom of the foundation pit, starting dewatering at least 10 days in advance for finishing dewatering operation, and performing integral large-surface earthwork excavation according to an excavation scheme;
(9) backfilling a dewatering well: and after the dewatering well is used, the water pump and the pipeline system are disassembled, and backfilling and tamping are carried out.
The embodiments of the present invention have been described in detail, but the description is only for the preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made within the scope of the present invention shall fall within the scope of the present invention.
Claims (6)
1. A foundation pit dewatering construction method is characterized by comprising the following construction steps:
(1) preparing for investigation: performing site investigation to find out the geological conditions and hydrological parameters of a site;
(2) designing a dewatering well: designing a dewatering well based on the geological conditions and the hydrological parameters to obtain dewatering well parameters and well bit data;
(3) the periphery of the foundation pit is connected with the wall: constructing a ground connecting wall at the periphery of the foundation pit, and sequentially penetrating geological soil layers through the ground connecting wall;
(4) and (3) measurement and paying-off: the method comprises the following steps of (1) carrying out field measurement, lofting and well positioning, and burying an opening protecting pipe at a well position;
(5) drilling to form a hole: drilling a dewatering well hole at a well position by using a drilling machine, and reinforcing the wall of the hole in the dewatering well hole drilling process;
(6) mounting a well pipe: after the well bore is lowered to the designed depth, cleaning the hole, putting the well bore into the well bore, adopting a sand-free concrete well bore, and filling a filter material between the well bore and the wall of the hole;
(7) well flushing: putting a sewage pump at the bottom of the dewatering well, injecting clear water into the dewatering well, and repeatedly pumping and washing by using the sewage pump to perform well washing operation until the water is sand-cleaned, thereby completing construction of the dewatering well;
(8) pumping water; installing a water pump and a pipeline system for pumping water; after the underground gushing water enters the precipitation well and reaches a preset height, the water pump is used for pumping the underground gushing water in the precipitation well to finish precipitation operation;
(9) backfilling a dewatering well: and after the dewatering well is used, the water pump and the pipeline system are disassembled, and backfilling and tamping are carried out.
2. The foundation pit dewatering construction method according to claim 1, wherein the dewatering well is structured to include: the well casing comprises a precipitation well hole, a well casing and a filler, wherein the well casing is arranged in the precipitation well hole, and the filler is filled between the well casing and the precipitation well hole.
3. A method for foundation pit dewatering construction according to claim 1, wherein the step (5) and the step (6) of drilling with a drilling rig to form a dewatering well comprises: burying a mouth protecting pipe at the actual position of each dewatering well to be constructed; the drilling machine aims at the central position of the protective pipe to carry out drilling construction to form a precipitation well hole; after the drilling is carried out to the designed well depth position, the dewatering well hole is punched by clear water to remove impurities in the dewatering well hole until mud returning from the dewatering well hole does not contain mud blocks; and (3) lowering the well pipe into the precipitation well hole, filling filler between the well pipe and the precipitation well hole and ensuring the well pipe to be vertical to form the precipitation well.
4. A method for dewatering foundation pits according to claim 3, wherein in step (5) the mud density in the dewatering well bore is controlled to be within a predetermined range during drilling construction, and the mud is pressed into the dewatering well bore to prevent the wall of the dewatering well bore from collapsing.
5. The foundation pit dewatering construction method according to claim 3, wherein the filter material in the step (6) is medium coarse sand and crushed stone chips with the particle size of 6-8 mm.
6. A method for lowering the water level in a foundation pit according to claim 1, wherein in the step (8), a water pump is used for pumping underground water gushing in the lowering well, so that the underground water level is lowered to be not less than 0.5m below the bottom of the foundation pit to finish the lowering operation.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010456011.6A CN111877377A (en) | 2020-05-26 | 2020-05-26 | Foundation pit dewatering construction method |
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| CN202010456011.6A CN111877377A (en) | 2020-05-26 | 2020-05-26 | Foundation pit dewatering construction method |
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| CN111877377A true CN111877377A (en) | 2020-11-03 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113250220A (en) * | 2021-05-13 | 2021-08-13 | 中铁五局集团成都工程有限责任公司 | Novel dewatering method for deep foundation pit close to existing building |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103866778A (en) * | 2012-12-10 | 2014-06-18 | 贵阳铝镁设计研究院有限公司 | Soft soil foundation deep foundation pit dewatering treatment method and structure |
| CN104032760A (en) * | 2013-03-05 | 2014-09-10 | 李孝虎 | Foundation pit construction tube well dewatering method |
| CN110093941A (en) * | 2019-04-25 | 2019-08-06 | 中铁十二局集团有限公司 | Deep foundation pit precipitation construction method |
| CN111139852A (en) * | 2020-01-07 | 2020-05-12 | 中交一公局第三工程有限公司 | Water-rich sandy gravel stratum high-permeability ultra-deep foundation pit dewatering construction method |
-
2020
- 2020-05-26 CN CN202010456011.6A patent/CN111877377A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103866778A (en) * | 2012-12-10 | 2014-06-18 | 贵阳铝镁设计研究院有限公司 | Soft soil foundation deep foundation pit dewatering treatment method and structure |
| CN104032760A (en) * | 2013-03-05 | 2014-09-10 | 李孝虎 | Foundation pit construction tube well dewatering method |
| CN110093941A (en) * | 2019-04-25 | 2019-08-06 | 中铁十二局集团有限公司 | Deep foundation pit precipitation construction method |
| CN111139852A (en) * | 2020-01-07 | 2020-05-12 | 中交一公局第三工程有限公司 | Water-rich sandy gravel stratum high-permeability ultra-deep foundation pit dewatering construction method |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113250220A (en) * | 2021-05-13 | 2021-08-13 | 中铁五局集团成都工程有限责任公司 | Novel dewatering method for deep foundation pit close to existing building |
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Application publication date: 20201103 |