CN112695779A - High-rise building foundation pit construction method for local precipitation of elevator shaft foundation pit - Google Patents

High-rise building foundation pit construction method for local precipitation of elevator shaft foundation pit Download PDF

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Publication number
CN112695779A
CN112695779A CN202110106213.2A CN202110106213A CN112695779A CN 112695779 A CN112695779 A CN 112695779A CN 202110106213 A CN202110106213 A CN 202110106213A CN 112695779 A CN112695779 A CN 112695779A
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CN
China
Prior art keywords
foundation pit
local
pit
steel sheet
sheet pile
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Pending
Application number
CN202110106213.2A
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Chinese (zh)
Inventor
常文慧
张银羽
李英霞
赵海燕
和慧泽
庞旭
李超
韩彦科
程亮平
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Shanxi Sanjian Group Co Ltd
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Shanxi Sanjian Group Co Ltd
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Priority to CN202110106213.2A priority Critical patent/CN112695779A/en
Publication of CN112695779A publication Critical patent/CN112695779A/en
Pending legal-status Critical Current

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    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D19/00Keeping dry foundation sites or other areas in the ground
    • E02D19/02Restraining of open water
    • E02D19/04Restraining of open water by coffer-dams, e.g. made of sheet piles
    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D17/00Excavations; Bordering of excavations; Making embankments
    • E02D17/02Foundation pits
    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D19/00Keeping dry foundation sites or other areas in the ground
    • E02D19/06Restraining of underground water
    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02DFOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D19/00Keeping dry foundation sites or other areas in the ground
    • E02D19/06Restraining of underground water
    • E02D19/10Restraining of underground water by lowering level of ground water

Abstract

The invention discloses a high-rise building foundation pit construction method for local precipitation of an elevator shaft foundation pit, which solves the problem of how to perform local precipitation of the elevator shaft and the water collection pit foundation pit. Including big foundation ditch (1) of whole building body, be provided with local foundation ditch (2) of elevartor shaft and sump pit at the bottom of the pit of big foundation ditch (1), be provided with confined steel sheet pile cofferdam (3) in the periphery of local foundation ditch (2), the bottom of the pit of local foundation ditch (2) in steel sheet pile cofferdam (3) is provided with precipitation well (4), precipitation well (4) comprise pre-buried no sand strainer (5) and waterproof sleeve pipe (6), immersible pump (7) have been put to the groundwater in precipitation well (4), be provided with rubble between precipitation well (4) and steel sheet pile cofferdam (3) and replace layer (8). The invention can locally reduce the water level of the area needing water level, greatly shorten the construction time, improve the efficiency and save the cost.

Description

High-rise building foundation pit construction method for local precipitation of elevator shaft foundation pit
Technical Field
The invention relates to a civil foundation pit dewatering system, in particular to a local dewatering system and a whole foundation pit construction method which are adopted when underground water does not appear at the bottom of a foundation pit with a large area excavated in the earthwork and only underground water appears in local areas of an elevator shaft foundation pit and a water collecting pit foundation pit.
Background
Some high-rise buildings are built in a soil layer environment with fine sand layers and sandy soil, the soil has poor shear resistance and is easy to collapse, and the type of underground water belongs to pore diving; and, according to the survey report show, the groundwater table buries deeply and is less than the foundation pit bottom of high-rise building, but is higher than the foundation pit bottom of elevartor shaft and sump pit in this building, when the earthwork excavates the basic foundation pit of large tracts of land high-rise building, can not appear groundwater, but when excavating still deeper elevartor shaft and sump pit foundation pit than large tracts of land foundation pit bottom, will appear groundwater in the foundation pit of elevartor shaft and sump pit, how carry out the local precipitation of the foundation pit of elevartor shaft and sump pit, become a technical problem that the site operation must solve.
In the process of constructing a foundation pit of a high-rise building, when the underground water level is lower than the bottom of the whole large foundation pit but higher than the bottom of a local foundation pit of an elevator shaft, a precipitation well is excavated around the whole foundation pit by a conventional method, and the whole foundation pit is constructed after the whole underground water is reduced to be below the bottom of the local foundation pit of the elevator shaft.
Disclosure of Invention
The invention provides a high-rise building foundation pit construction method for local precipitation of an elevator shaft foundation pit, and solves the technical problem of how to perform local precipitation of the elevator shaft and the water collection pit foundation pit.
The invention solves the technical problems by the following technical scheme:
the general concept of the invention is: when the underground water level is higher than the elevation of the bottom of the local foundation pit of the elevator shaft and the water collecting pit, arranging a closed steel sheet pile cofferdam at the periphery of the local foundation pit of the elevator shaft and the water collecting pit, arranging a precipitation well at the position of the local foundation pit, wherein the depth of the steel sheet pile cofferdam is larger than that of the precipitation well, pumping water and precipitating water by a submersible pump in the precipitation well to stably reduce the underground water to be below the bottom of the local foundation pit, starting to construct bottom ribs and side wall vertical reinforcing steel bars of the local foundation pit, and pouring micro-expansion impervious concrete to form the outline of the local foundation pit; sequentially taking out the submersible pump, the waterproof casing and the sand-free water filter pipe at the uppermost section, and sealing the sand-free water filter pipe of the dewatering well by using micro-expansive impervious concrete; sequentially arranging a cement permeable crystallization layer and two SBS modified asphalt waterproof coil layers with the thickness of 4 mm on the micro-expansion impervious concrete at the well mouth of the closed dewatering well and the bottom of the local foundation pit, and pouring a C20 fine stone concrete waterproof protective layer with the thickness of 50 mm, wherein after the dewatering well is closed, when the waterproof layer is laid, underground water needs to bypass the closed steel sheet pile cofferdam and enter the steel sheet pile cofferdam, so that the underground water in the steel sheet pile cofferdam slowly rises and cannot rise beyond the position of the waterproof layer, and the reliable construction of the waterproof layer is ensured; in the whole construction process, the steel sheet pile cofferdam is not taken out; although the steel sheet pile cofferdam around the local foundation pit is lost, the steel sheet pile cofferdam does not need to be arranged at the periphery of the whole large foundation pit, and the construction cost is greatly saved overall.
The utility model provides an elevator shaft foundation ditch local precipitation system, includes the big foundation ditch of whole building body, is provided with the local foundation ditch of elevartor shaft and sump pit at the bottom of the hole of big foundation ditch, is provided with confined steel sheet pile cofferdam in the periphery of local foundation ditch, is provided with the precipitation well at the bottom of the local foundation ditch in the steel sheet pile cofferdam, and the precipitation well comprises pre-buried no sand strainer and waterproof sleeve pipe, has put the immersible pump in the groundwater in the precipitation well, is provided with the rubble and replaces the layer between precipitation well and steel sheet pile cofferdam.
The depth of the dewatering well is 2-3 meters, the depth of the steel sheet pile cofferdam is 7-8 meters, the thickness of the gravel replacement layer is 2 meters, and the gravel replacement layer is arranged below the bottom of the local foundation pit.
A high-rise building foundation pit construction method for local precipitation of an elevator shaft foundation pit comprises the following steps:
firstly, excavating a large foundation pit of the whole building body, wherein the bottom of the large foundation pit is higher than the buried depth water level of underground water;
secondly, driving a steel sheet pile cofferdam downwards at the pit bottom of a large foundation pit at the periphery of a local foundation pit of the elevator shaft and the sump to be arranged, wherein the depth of the steel sheet pile cofferdam is 7-8 m, and the upper end of the steel sheet pile cofferdam is lower than the pit bottom surface of the large foundation pit;
excavating a soil body of a local foundation pit in the steel sheet pile cofferdam, wherein in the downward excavation process, the underground water level is higher than the bottom of the local foundation pit, the downward excavation depth is 1 meter deeper than the bottom of the local foundation pit, and after the excavation is finished, a broken stone replacement layer is backfilled;
fourthly, drilling a well hole of a dewatering well downwards on the backfilled gravel replacement layer, and putting a sand-free water filter pipe and a waterproof casing pipe in the well hole to form the dewatering well, wherein the depth of the dewatering well is 2-3 m;
fifthly, putting a submersible pump in the underground water of the dewatering well to pump water and dewater, arranging bottom ribs and side wall vertical reinforcing steel bars of the local foundation pit of the elevator shaft and the water collecting pit on the gravel replacing layer after the underground water descends and is stabilized below the bottom of the local foundation pit, and pouring micro-expansion impervious concrete to form the outline of the local foundation pit;
sixthly, backfilling and compacting plain soil between the contour of the formed local foundation pit and the steel sheet pile cofferdam;
seventhly, taking out the submersible pump, and sealing a sand-free water filtering pipe of the dewatering well by using micro-expansion impervious concrete;
eighthly, arranging a cement permeable crystallization layer on the closed wellhead of the dewatering well and the micro-expansion impervious concrete at the bottom of the local foundation pit;
ninth, paving two SBS modified asphalt waterproof coil layers with the thickness of 4 mm on the cement capillary crystalline layer;
tenth, pouring a C20 fine-stone concrete waterproof protective layer with the thickness of 50 mm on the SBS modified asphalt waterproof roll layer;
and step ten, after a reinforcing steel bar system of the large foundation pit and the local foundation pit is constructed, pouring the foundation pit concrete at one time.
The invention can locally reduce the water level of the area needing water level, greatly shorten the construction time, improve the efficiency and save the cost.
Drawings
FIG. 1 is a schematic structural view of the present invention;
fig. 2 is a schematic structural view in a top view direction of the present invention.
Detailed Description
The invention is described in detail below with reference to the accompanying drawings:
the utility model provides an elevator shaft foundation pit local precipitation system, including the big foundation pit 1 of whole building body, be provided with the local foundation pit 2 of elevartor shaft and sump pit at the bottom of the pit of big foundation pit 1, be provided with confined steel sheet pile cofferdam 3 in the periphery of local foundation pit 2, the bottom of the pit of local foundation pit 2 in steel sheet pile cofferdam 3 is provided with precipitation well 4, precipitation well 4 comprises pre-buried no sand strainer 5 and waterproof sleeve 6, immersible pump 7 has been put down in the groundwater in precipitation well 4, be provided with rubble replacement layer 8 between precipitation well 4 and steel sheet pile cofferdam 3.
The depth of the dewatering well 4 is 2-3 meters, the depth of the steel sheet pile cofferdam 3 is 7-8 meters, and the thickness of the gravel replacement layer 8 is 2 meters, and the gravel replacement layer is arranged below the bottom of the local foundation pit 2.
A high-rise building foundation pit construction method for local precipitation of an elevator shaft foundation pit comprises the following steps:
firstly, excavating a large foundation pit 1 of the whole building body, wherein the pit bottom of the large foundation pit 1 is higher than the buried water level of underground water;
secondly, driving a steel sheet pile cofferdam 3 downwards at the pit bottom of a large foundation pit 1 at the periphery of a local foundation pit 2 of the elevator shaft and the sump to be arranged, wherein the depth of the steel sheet pile cofferdam 3 is 7-8 m, and the upper end of the steel sheet pile cofferdam 3 is lower than the pit bottom surface of the large foundation pit 1;
excavating the soil body of the local foundation pit 3 in the steel sheet pile cofferdam 3, wherein in the downward excavation process, the underground water level is higher than the bottom of the local foundation pit 3, the downward excavation depth is 1 meter deeper than the bottom of the local foundation pit 3, and after the excavation is finished, a broken stone replacement layer 8 is backfilled;
fourthly, drilling a well hole of a dewatering well downwards on the backfilled gravel replacement layer 8, and putting a sand-free filter pipe 5 and a waterproof casing 6 in the well hole to form the dewatering well 4, wherein the depth of the dewatering well 4 is 2-3 m;
fifthly, lowering a submersible pump 7 in the underground water of the dewatering well 4 to pump water and dewater, after the underground water descends and is stabilized below the bottom of the local foundation pit 3, arranging bottom ribs and side wall vertical reinforcing steel bars of the local foundation pit 2 of the elevator shaft and the water collecting pit on a broken stone replacement layer 8, and pouring micro-expansion impervious concrete 10 to form the outline of the local foundation pit 2;
sixthly, backfilling and tamping plain soil between the contour of the formed local foundation pit 2 and the steel sheet pile cofferdam 3;
seventhly, taking out the submersible pump 7, and sealing the sand-free water filter pipe 5 of the dewatering well 4 by using micro-expansion impervious concrete;
eighthly, arranging a cement permeable crystallization layer 11 on the closed wellhead of the dewatering well 4 and the micro-expansion impervious concrete at the bottom of the local foundation pit 2;
step nine, paving two SBS modified asphalt waterproof coil layers 12 with the thickness of 4 mm on the cement capillary crystalline layer 11;
tenth, pouring a C20 fine-stone concrete waterproof protective layer 13 with the thickness of 50 mm on the SBS modified asphalt waterproof roll layer 12;
and step eleven, after a reinforcing steel bar system of the large foundation pit 1 and the local foundation pit 2 is constructed, pouring the foundation pit concrete 14 at one time.

Claims (1)

1. A high-rise building foundation pit construction method for local precipitation of an elevator shaft foundation pit comprises the following steps:
firstly, excavating a large foundation pit (1) of the whole building body, wherein the bottom of the large foundation pit (1) is higher than the buried depth water level of underground water;
secondly, driving a steel sheet pile cofferdam (3) downwards at the bottom of a large foundation pit (1) at the periphery of a local foundation pit (2) of the elevator shaft and the sump to be arranged, wherein the depth of the steel sheet pile cofferdam (3) is 7-8 meters, and the upper end of the steel sheet pile cofferdam (3) is lower than the bottom surface of the large foundation pit (1);
thirdly, excavating the soil body of the local foundation pit (3) in the steel sheet pile cofferdam (3), wherein in the downward excavation process, as the underground water level is higher than the bottom of the local foundation pit (3), the downward excavation depth is 1 meter deeper than the bottom of the local foundation pit (3), and backfilling a broken stone replacement layer (8) after the excavation is finished;
fourthly, drilling a well hole of a dewatering well downwards on the backfilled gravel replacement layer (8), and placing a sand-free water filter pipe (5) and a waterproof casing pipe (6) in the well hole to form the dewatering well (4), wherein the depth of the dewatering well (4) is 2-3 m;
fifthly, a submersible pump (7) is placed in the underground water of the dewatering well (4) to pump water and dewater, after the underground water descends and is stabilized below the bottom of the local foundation pit (3), a bottom rib and a side wall vertical reinforcing steel bar of the local foundation pit (2) of the elevator shaft and the water collecting pit are arranged on a gravel replacing layer (8), and micro-expansion impervious concrete (10) is poured to form the outline of the local foundation pit (2);
sixthly, backfilling and compacting plain soil between the contour of the formed local foundation pit (2) and the steel sheet pile cofferdam (3);
seventhly, taking out the submersible pump (7), and sealing the sand-free water filter pipe (5) of the dewatering well (4) by using micro-expansion impervious concrete;
eighthly, arranging a cement permeable crystallization layer (11) on the micro-expansion impervious concrete at the wellhead of the closed dewatering well (4) and the bottom of the local foundation pit (2);
ninth, paving two SBS modified asphalt waterproof coil layers (12) with the thickness of 4 mm on the cement permeable crystallization layer (11);
tenth, pouring a C20 fine aggregate concrete waterproof protective layer (13) with the thickness of 50 mm on the SBS modified asphalt waterproof roll layer (12);
and step ten, after a steel bar system of the large foundation pit (1) and the local foundation pit (2) is constructed, the foundation pit concrete (14) is cast at one time.
CN202110106213.2A 2021-01-26 2021-01-26 High-rise building foundation pit construction method for local precipitation of elevator shaft foundation pit Pending CN112695779A (en)

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Application Number Priority Date Filing Date Title
CN202110106213.2A CN112695779A (en) 2021-01-26 2021-01-26 High-rise building foundation pit construction method for local precipitation of elevator shaft foundation pit

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114908782A (en) * 2021-12-21 2022-08-16 中国化学工程第四建设有限公司 Foundation pit dewatering construction method

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006194031A (en) * 2005-01-17 2006-07-27 Ps Mitsubishi Construction Co Ltd Pillar construction method
CN101768976A (en) * 2009-12-29 2010-07-07 中建城市建设发展有限公司 Base pit dewatering and water saving device and construction method thereof
CN102877420A (en) * 2012-11-06 2013-01-16 中铁二十二局哈尔滨铁路建设集团有限责任公司 Construction method of large tube well fixed point precipitation, sealing bottom free concrete and steel sheet pile cofferdam deepwater bearing platform
CN103161172A (en) * 2012-05-29 2013-06-19 中国二十二冶集团有限公司 Elevator shaft bottom precipitation construction method

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006194031A (en) * 2005-01-17 2006-07-27 Ps Mitsubishi Construction Co Ltd Pillar construction method
CN101768976A (en) * 2009-12-29 2010-07-07 中建城市建设发展有限公司 Base pit dewatering and water saving device and construction method thereof
CN103161172A (en) * 2012-05-29 2013-06-19 中国二十二冶集团有限公司 Elevator shaft bottom precipitation construction method
CN102877420A (en) * 2012-11-06 2013-01-16 中铁二十二局哈尔滨铁路建设集团有限责任公司 Construction method of large tube well fixed point precipitation, sealing bottom free concrete and steel sheet pile cofferdam deepwater bearing platform

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114908782A (en) * 2021-12-21 2022-08-16 中国化学工程第四建设有限公司 Foundation pit dewatering construction method

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Application publication date: 20210423