CN116084432A - Reinforcing method for controlling local large deformation of foundation pit - Google Patents
Reinforcing method for controlling local large deformation of foundation pit Download PDFInfo
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- CN116084432A CN116084432A CN202310059951.5A CN202310059951A CN116084432A CN 116084432 A CN116084432 A CN 116084432A CN 202310059951 A CN202310059951 A CN 202310059951A CN 116084432 A CN116084432 A CN 116084432A
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- foundation pit
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- reinforcement
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- 238000000034 method Methods 0.000 title claims abstract description 30
- 230000003014 reinforcing effect Effects 0.000 title claims abstract description 13
- 230000002787 reinforcement Effects 0.000 claims abstract description 35
- 239000002689 soil Substances 0.000 claims abstract description 30
- 238000009412 basement excavation Methods 0.000 claims abstract description 8
- 238000004062 sedimentation Methods 0.000 claims abstract description 4
- 238000005728 strengthening Methods 0.000 claims abstract description 4
- 229910000831 Steel Inorganic materials 0.000 claims description 12
- 239000010959 steel Substances 0.000 claims description 12
- 238000010276 construction Methods 0.000 abstract description 18
- 230000000694 effects Effects 0.000 abstract description 4
- 238000012954 risk control Methods 0.000 abstract description 4
- 101150054854 POU1F1 gene Proteins 0.000 description 14
- 239000004567 concrete Substances 0.000 description 5
- 238000006073 displacement reaction Methods 0.000 description 2
- 230000002265 prevention Effects 0.000 description 2
- 239000011150 reinforced concrete Substances 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
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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
- E02D17/04—Bordering surfacing or stiffening the sides of foundation pits
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
- E02D5/22—Piles
- E02D5/34—Concrete or concrete-like piles cast in position ; Apparatus for making same
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
- E02D5/74—Means for anchoring structural elements or bulkheads
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A10/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE at coastal zones; at river basins
- Y02A10/23—Dune restoration or creation; Cliff stabilisation
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- Engineering & Computer Science (AREA)
- Structural Engineering (AREA)
- Mining & Mineral Resources (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Paleontology (AREA)
- Civil Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Foundations (AREA)
Abstract
The invention discloses a strengthening method for controlling local large deformation of a foundation pit, which comprises the following steps: firstly, arranging a soil piling back pressure area at the lower part of the inner side of a deformation area of a foundation pit; then constructing a plurality of anchor cables which incline downwards from the inner wall of the deformation area of the foundation pit to the soil body outside the foundation pit; and finally, constructing vertical reinforcing piles at the position, which is close to the building envelope, of the existing building, on the outer side of the deformation area of the foundation pit, and finishing reinforcement. The method adopts the reinforcement measures such as the outer seal inner row, the pile soil back pressure, the anchor cable and the like, and in the process of excavation, soil bodies between the newly built foundation pit and the existing building are timely and effectively reinforced, so that the old building sedimentation deformation damage and the newly built foundation pit horizontal deformation damage caused by the instability of the slope in the pit are prevented, the foundation pit construction is effectively ensured to be safely and efficiently carried out under a plurality of serious risks, and the targeted risk control reinforcement is respectively adopted for the slope in the pit and the community enclosing wall, so that the risk control effect is excellent.
Description
Technical Field
The invention relates to the technical field of building reinforcement, in particular to a reinforcement method for controlling local large deformation of a foundation pit.
Background
Along with the rapid development of urban rail transit, the construction of stations is the most important component in the whole engineering in the subway construction process, and the prevention of foundation pit deformation and damage is particularly important. The foundation pit supporting structure adopts pile anchors for supporting, the construction of an open cut method needs to consider factors such as construction progress, weather influence and the like, stratum settlement and displacement must be strictly controlled so as to avoid serious consequences, and particularly in gravel stratum, soil body micro-expansion is caused after long-time rain attack, and soil body instability is caused.
Local deformation generated in the foundation pit engineering construction process is frequent, particularly, a larger height difference exists between the existing building and the newly-built foundation pit, a slope structure is formed, and deformation is easy to cause. However, after the foundation pit support structures adjacent to old buildings are greatly deformed, the reinforcement schemes on how to perform rapid and safe reinforcement measures to prevent further deformation of the support piles and instability of surrounding soil bodies are less.
Disclosure of Invention
The invention aims to provide a reinforcing method for controlling local large deformation of a foundation pit, aiming at the defects of deformation of a foundation pit support structure of an immediately old building and prevention of further deformation and even soil instability after the building subsides in the prior art.
In order to achieve the above object, the present invention provides the following technical solutions:
a strengthening method for controlling local large deformation of a foundation pit comprises the following steps:
a. a soil piling back pressure area is arranged at the lower part of the inner side of the deformation area of the foundation pit;
b. constructing a plurality of anchor cables obliquely downwards from the inner wall of the deformation area of the foundation pit to the soil body outside the foundation pit;
c. and constructing vertical reinforcing piles at the position, close to the building envelope, of the existing building outside the deformation area of the foundation pit, and finishing reinforcement.
According to the reinforcement method for controlling the local large deformation of the foundation pit, reinforcement measures such as the outer seal inner row, the pile soil back pressure and the anchor cable are adopted, pile soil back pressure can be quickly and effectively restrained under the condition that the horizontal displacement of the fender pile is suddenly changed, soil reinforcement and restraint of the deformation of the existing building enclosure structure can be effectively carried out, the anchor cable and the reinforcement pile can ensure that the soil between a newly built foundation pit and the existing building can be effectively reinforced in time in the excavation process, further the settlement deformation damage of the old building and the horizontal deformation damage of the newly built foundation pit caused by the instability of the slope in the pit are prevented, the safe and efficient foundation pit construction is effectively ensured under a plurality of serious risks, the reinforcement is respectively controlled by adopting specific risks on the side slope in the pit and the community, the risk control effect is excellent, timely and quick limitation of deformation is facilitated, further enlargement of the deformation is prevented, guarantee is provided for normal construction, the reinforcement period is short, the negative influence caused by the deformation and settlement of the building caused by the rapid recovery of normal orderly construction is reduced, and the risk grade is reduced.
Preferably, the step a further comprises: and constructing a waist beam at the top of the pile soil back pressure area, constructing a ground beam at the bottom of the foundation pit, and arranging a supporting piece between the waist beam and the ground beam.
Further preferably, the height of the pile back pressure zone is 1/2-2/3 of the depth of the foundation pit.
Further prevent newly-built foundation ditch deformation increase.
Further preferably, the anchor lines are distributed along the height direction of the foundation pit, and the anchor lines positioned at the lowest row are lower than the top surface of the pile back pressure area.
Preferably, in said step b, a prestressing force is applied to said cable.
Preferably, between the steps a and b, further comprising: and a steel pipe support is arranged along the outer side of the enclosure structure, and an inclined strut is arranged on the outer side of the steel pipe support.
The enclosure structure is temporarily supported, and can be removed after the reinforcing piles are constructed.
Further preferably, the reinforcement pile is a micro filling pile, the depth of the micro filling pile exceeds the position of the foundation pit where the horizontal deformation of the guard pile is maximum, and the diameter of the micro filling pile is smaller than or equal to 146mm.
The depth of the miniature filling pile is lower than the position with the maximum horizontal deformation of the guard pile, such as a pile breaking position, so as to stabilize soil body, and the miniature filling pile is required to be arranged according to stratum conditions and enter a bearing layer.
Further preferably, the micro filling pile is internally provided with reinforcing ribs, and the micro filling pile adopts pressure grouting.
The method can effectively reduce disturbance to the existing building, can rapidly complete emergency construction, shortens construction period, strengthens control of adverse effect of compressed air on environment, and has no influence on surrounding environment protection.
Preferably, after the horizontal deformation of the support piles of the foundation pit and the sedimentation deformation of the existing building are stable, the pile soil back pressure area is gradually removed along with the excavation of the foundation pit.
In summary, compared with the prior art, the invention has the following beneficial effects:
1. the reinforcement method for controlling the local large deformation of the foundation pit adopts the reinforcement measures such as the outer sealing inner row, the pile soil back pressure, the anchor cable and the like, and the soil body between the newly built foundation pit and the existing building is effectively reinforced in time in the excavation process, so that the settlement deformation damage of the old building and the horizontal deformation damage of the newly built foundation pit caused by the instability of the slope in the pit are prevented, the foundation pit construction is effectively ensured to be safely and efficiently carried out under a plurality of serious risk conditions, the reinforcement is respectively controlled by adopting the targeted risk to the slope in the pit and the community enclosing wall, the risk control effect is excellent, the timely and rapid deformation limitation is facilitated, the further enlargement of the deformation is prevented, the guarantee is provided for the normal operation of the construction, the reinforcement construction period is short, the normal and orderly construction is quickly recovered, the social negative influence caused by the deformation settlement of the building caused by the excavation of the foundation pit is reduced, and the risk grade is reduced.
Description of the drawings:
fig. 1 is a schematic cross-sectional view of a reinforced foundation pit according to embodiment 1 by a reinforcing method for controlling local large deformation.
The marks in the figure: 1-foundation pit, 2-pile soil back pressure area, 3-waist beam, 4-ground beam, 5-enclosure structure, 6-steel pipe bracket, 7-diagonal bracing, 8-reinforcing pile and 9-anchor cable.
Detailed Description
The invention is described in further detail below with reference to the accompanying drawings and specific examples. It should not be construed that the scope of the above subject matter of the present invention is limited to the following embodiments, and all techniques realized based on the present invention are within the scope of the present invention.
Example 1
The invention relates to a strengthening method for controlling local large deformation of a foundation pit, which comprises the following steps:
a. a soil piling back pressure area 2 is arranged at the lower part of the inner side of the deformation area of the foundation pit 1;
b. constructing a plurality of anchor cables 9 obliquely downwards from the inner wall of the deformation area of the foundation pit 1 to the soil body outside the foundation pit 1;
c. and constructing vertical reinforcing piles 8 at the position, close to the building envelope 5, of the existing building, outside the deformation area of the foundation pit 1, so as to finish reinforcement.
Specifically, firstly, a pile back pressure region 2 is arranged at a side pit angle in a deformation region of a foundation pit 1, the pile amount and the pile height are set according to deformation control requirements, the pile height is preferably more than 1/2-2/3 of the depth of the foundation pit 1, then a reinforced concrete waist beam 3 is constructed above the pile back pressure region 2, after the concrete of the waist beam 3 reaches 75% strength, a reinforced concrete land beam 4 is vertically excavated downwards at the bottom of the foundation pit 1, such as about 2m, an inclined steel support piece is arranged between the waist beam 3 and the land beam 4, the stability of a fender post of the foundation pit 1 is further ensured, further horizontal deformation is prevented, and after the deformation is stable, the construction of subsequent anchor cables and reinforcing piles is performed.
A row of steel pipe supports 6 are arranged on the outer side of the enclosure structure 5 and are tightly attached to the enclosure structure 5 to serve as temporary supporting devices, inclined struts 7 are arranged on the outer side of the steel pipe supports 6, after the steel pipe supports 6 and the inclined struts 7 are stably installed, a plurality of anchor ropes 9 which are downward inclined are constructed from the inner wall of a deformation area of the foundation pit 1 to soil on the outer side of the foundation pit 1, parameters such as the number, the distance and the diameter of the anchor ropes 9 are set according to reinforcing requirements, the anchor ropes 9 are distributed along the height direction of the foundation pit 1, the anchor ropes 9 which are located on the lowest row are lower than the top surface of the soil piling back pressure area 2, tensile prestress is supplemented for the anchor ropes 9, and specific tensile force is determined according to actual requirements.
Then, a vertical reinforcement pile 8 is tightly attached to the outer side of the enclosure structure 5, and after reinforcement is completed, the steel pipe support 6 and the diagonal brace 7 can be removed after the construction of the reinforcement pile 8 is completed as shown in fig. 1. The reinforced pile 8 is a miniature bored concrete pile, the diameter and depth of the miniature bored concrete pile are set according to actual conditions, the depth of the miniature bored concrete pile exceeds the position with the maximum horizontal deformation of the guard pile of the foundation pit 1, the diameter of the miniature bored concrete pile is smaller than or equal to 146mm, such as a pore-forming diameter DN146, a DN65 steel pipe is inserted, triangular ribs in the steel pipe are reinforced, and pressure thick slurry is used for grouting.
And after the horizontal deformation of the support piles of the foundation pit 1 and the sedimentation deformation of the existing building are stable, gradually removing the pile soil back pressure area 2 along with the excavation of the foundation pit 1.
The reinforcement method adopts reinforcement measures such as an outer seal inner row, a pile soil back pressure, an anchor rope and the like, and effectively and timely reinforces soil between a newly built foundation pit and an existing building in the excavation process, thereby preventing old building settlement deformation damage and new foundation pit horizontal deformation damage caused by instability of a side slope in the pit, effectively ensuring the safe and efficient foundation pit construction under a plurality of serious risks.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention.
Claims (9)
1. The strengthening method for controlling the local large deformation of the foundation pit is characterized by comprising the following steps of:
a. a soil piling back pressure area (2) is arranged at the lower part of the inner side of the deformation area of the foundation pit (1);
b. constructing a plurality of anchor cables (9) obliquely downwards from the inner wall of the deformation area of the foundation pit (1) to the soil body outside the foundation pit (1);
c. and constructing vertical reinforcing piles (8) at the position, close to the building envelope (5), of the existing building, outside the deformation area of the foundation pit (1) to finish reinforcement.
2. The reinforcement method for controlling local large deformation of foundation pit according to claim 1, wherein said step a further comprises: and constructing a waist beam (3) at the top of the pile soil back pressure area (2), constructing a ground beam (4) at the bottom of the foundation pit (1), and arranging a supporting piece between the waist beam (3) and the ground beam (4).
3. A reinforcement method for controlling local large deformations of foundation pit according to claim 1, characterized in that the height of the pile back pressure zone (2) is 1/2-2/3 of the depth of the foundation pit (1).
4. A reinforcement method for controlling local large deformations of foundation pit according to claim 3, characterized in that the anchor lines (9) are distributed along the height of the foundation pit (1), the anchor lines (9) in the lowest row being below the top surface of the pile back pressure zone (2).
5. A reinforcement method for controlling local large deformations of foundation pit according to claim 1, characterized in that said step b further comprises prestressing said anchor lines (9).
6. A reinforcement method for controlling localized large deformations of foundation pit according to claim 1, further comprising, between said steps a and b: a steel pipe support (6) is arranged along the outer side of the enclosure structure (5), and a diagonal bracing (7) is arranged on the outer side of the steel pipe support (6).
7. The reinforcement method for controlling local large deformation of foundation pit according to claim 6, wherein the reinforcement pile (8) is a micro cast-in-place pile, the depth of which exceeds the position of maximum horizontal deformation of the fender pile of the foundation pit (1), and the diameter of which is less than or equal to 146mm.
8. The reinforcement method for controlling local large deformation of foundation pit according to claim 7, wherein the mini-cast-in-place pile is internally provided with reinforcing ribs, and the mini-cast-in-place pile is pressure grouting.
9. A reinforcement method for controlling local large deformations of foundation pit according to any one of claims 1-8, characterized in that the pile back-pressure zone (2) is gradually removed with the excavation of the foundation pit (1) after the horizontal deformations of the support piles of the foundation pit (1) and the sedimentation deformations of the existing building are stabilized.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310059951.5A CN116084432A (en) | 2023-01-18 | 2023-01-18 | Reinforcing method for controlling local large deformation of foundation pit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310059951.5A CN116084432A (en) | 2023-01-18 | 2023-01-18 | Reinforcing method for controlling local large deformation of foundation pit |
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| CN116084432A true CN116084432A (en) | 2023-05-09 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202310059951.5A Pending CN116084432A (en) | 2023-01-18 | 2023-01-18 | Reinforcing method for controlling local large deformation of foundation pit |
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN203320532U (en) * | 2013-04-28 | 2013-12-04 | 中南大学 | Protection device of nearby pile foundation close to deep foundation pit |
| CN106638622A (en) * | 2017-02-20 | 2017-05-10 | 中车建设工程有限公司 | Foundation pit temporary supporting structure and foundation pit construction method for preventing adjacent building foundation from deforming |
| CN108978676A (en) * | 2018-09-04 | 2018-12-11 | 北京市机械施工有限公司 | A kind of construction method of foundation pit group and basic pile group |
| US20210040703A1 (en) * | 2019-08-09 | 2021-02-11 | Guangzhou Institute Of Building Science Co., Ltd. | Construction method for foundation pit support utilizing prefabricated large-diameter pipe pile |
| CN112779914A (en) * | 2021-01-06 | 2021-05-11 | 上海智平基础工程有限公司 | Inclined strut structure and construction method for combined support in foundation pit |
| CN214363508U (en) * | 2020-12-31 | 2021-10-08 | 北京中岩大地科技股份有限公司 | Foundation pit supporting structure |
| CN218880889U (en) * | 2023-01-18 | 2023-04-18 | 中国铁建昆仑投资集团有限公司 | Reinforcing structure for controlling local large deformation of foundation pit |
-
2023
- 2023-01-18 CN CN202310059951.5A patent/CN116084432A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN203320532U (en) * | 2013-04-28 | 2013-12-04 | 中南大学 | Protection device of nearby pile foundation close to deep foundation pit |
| CN106638622A (en) * | 2017-02-20 | 2017-05-10 | 中车建设工程有限公司 | Foundation pit temporary supporting structure and foundation pit construction method for preventing adjacent building foundation from deforming |
| CN108978676A (en) * | 2018-09-04 | 2018-12-11 | 北京市机械施工有限公司 | A kind of construction method of foundation pit group and basic pile group |
| US20210040703A1 (en) * | 2019-08-09 | 2021-02-11 | Guangzhou Institute Of Building Science Co., Ltd. | Construction method for foundation pit support utilizing prefabricated large-diameter pipe pile |
| CN214363508U (en) * | 2020-12-31 | 2021-10-08 | 北京中岩大地科技股份有限公司 | Foundation pit supporting structure |
| CN112779914A (en) * | 2021-01-06 | 2021-05-11 | 上海智平基础工程有限公司 | Inclined strut structure and construction method for combined support in foundation pit |
| CN218880889U (en) * | 2023-01-18 | 2023-04-18 | 中国铁建昆仑投资集团有限公司 | Reinforcing structure for controlling local large deformation of foundation pit |
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