CN115125960B - Common foundation pit excavation method for foundation pits with different bottom elevations and close to each other - Google Patents
Common foundation pit excavation method for foundation pits with different bottom elevations and close to each other Download PDFInfo
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- 238000009412 basement excavation Methods 0.000 title claims abstract description 85
- 238000000034 method Methods 0.000 title claims abstract description 31
- 238000010276 construction Methods 0.000 claims abstract description 134
- 238000013461 design Methods 0.000 claims abstract description 35
- 238000005457 optimization Methods 0.000 claims abstract description 9
- 238000012790 confirmation Methods 0.000 claims abstract description 4
- 229910000831 Steel Inorganic materials 0.000 claims description 55
- 239000010959 steel Substances 0.000 claims description 55
- 239000000758 substrate Substances 0.000 claims description 35
- 239000007921 spray Substances 0.000 claims description 20
- 230000002787 reinforcement Effects 0.000 claims description 10
- 239000002689 soil Substances 0.000 claims description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 6
- 238000013508 migration Methods 0.000 claims description 4
- 230000005012 migration Effects 0.000 claims description 4
- 238000012986 modification Methods 0.000 claims description 4
- 230000004048 modification Effects 0.000 claims description 4
- 238000001514 detection method Methods 0.000 claims description 3
- 239000004575 stone Substances 0.000 claims description 2
- 101150054854 POU1F1 gene Proteins 0.000 description 7
- 102000001999 Transcription Factor Pit-1 Human genes 0.000 description 7
- 108010040742 Transcription Factor Pit-1 Proteins 0.000 description 7
- 239000011435 rock Substances 0.000 description 5
- 239000002893 slag Substances 0.000 description 5
- 238000012544 monitoring process Methods 0.000 description 4
- 238000007796 conventional method Methods 0.000 description 3
- 238000005422 blasting Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000011218 segmentation Effects 0.000 description 2
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- 230000009286 beneficial effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 238000010079 rubber tapping Methods 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 238000005728 strengthening Methods 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
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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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Abstract
The method for excavating the foundation pit in the vicinity of the foundation pit with different bottom elevations comprises the following steps: firstly, determining an optimization scheme of an enclosure structure in advance according to the enclosure structure form of a common foundation pit section; secondly, the optimized building envelope is communicated with a design, supervision and owners to perfect a new construction scheme before construction, and the building envelope construction is carried out after confirmation and optimization; thirdly, determining excavation steps and construction parameters according to the optimized form of the enclosure structure; fourth, the site construction is carried out according to the construction scheme, and each procedure, construction parameters and the like are strictly carried out according to the requirements of the construction scheme. The excavation method can reduce construction cost and shorten construction period on the premise of ensuring the safety of the foundation pit.
Description
Technical Field
The invention relates to the technical field of foundation pit construction, in particular to a common foundation pit excavation method for foundation pits with different bottom elevations.
Background
In the current underground construction, due to the crowding of underground space, the construction of an immediate structure is already a normal state, various building enclosure reinforcement, foundation strengthening measures and the like are derived, and a lot of resource waste is caused in an intangible way. In recent years, the economy of China is developed at a high speed, the construction of infrastructure in cities is perfected, the construction scale of urban rail transit is perfected, the urban with developed economy is preferentially selected to develop underground traffic, the underground space of the urban with developed economy is crowded, the underground is used as the main construction site of urban rail transit, various underground buildings such as subways, underground parking lots, pipes, underground channels, building foundations and the like are distributed in the underground space with not rich space, and therefore in the construction process of the underground space, not only the existing building foundations are needed to be avoided, but also various safety distances are considered. It is also contemplated that the construction site can provide adequate floor site support. The open cut method is a construction method widely adopted by underground traffic, and has higher requirements on sites, and the underground construction needs to consider a slag soil site for circulating slag soil, a stacking area for materials and supplies and the like, so that the construction site is further compressed.
The conventional method for constructing the foundation pit in close proximity has the following two problems: first: the resource is wasted, the cost is increased, the protection and the reinforcement of the enclosure structure are needed to be considered by taking the protection measures of the adjacent foundation pit into consideration, the investment of manpower, financial resources and machine equipment is increased, the resource is wasted, and the cost is increased; second,: the overall flowing step distance is increased due to the increase of the working procedures, so that the construction progress is slowed down, and the total construction period is prolonged.
Therefore, there is a need for a method for excavating foundation pits in close proximity to foundation pits at different bottom elevations that improves upon the deficiencies of the prior art.
Disclosure of Invention
The invention aims to overcome the defects in the prior art, and provides a construction scheme capable of reducing construction cost and shortening construction period on the premise of ensuring the safety of a foundation pit.
In order to achieve the above object, the present invention provides the following technical solutions:
the method for excavating the foundation pit in the vicinity of the foundation pit with different bottom elevations comprises the following steps:
Firstly, determining an optimization scheme of an enclosure structure in advance according to an enclosure structure form of a common foundation pit section, wherein a first foundation pit and a second foundation pit are adjacent foundation pits, preparing the two adjacent foundation pits for common foundation pit excavation, and the substrate elevations of the first foundation pit and the second foundation pit are different; the excavation of the common foundation pit is as follows: the first foundation pit and the second foundation pit are close to each other, the guard piles on the adjacent sides of the first foundation pit and the second foundation pit are shared piles, and the first foundation pit and the second foundation pit are combined into a large foundation pit;
Secondly, the optimized building envelope is communicated with a design, supervision and owners to perfect a new construction scheme before construction, and the building envelope construction is carried out after confirmation and optimization;
thirdly, determining excavation steps and construction parameters according to the optimized form of the enclosure structure;
The excavation step sequence of the common foundation pit is as follows: s1: constructing an enclosure structure, evaluating a foundation pit excavation and supporting construction scheme, and determining excavation steps and construction parameters; s2: foundation pit layered and sectional excavation, supporting and supporting construction, foundation pit detection, foundation pit deformation and safety assessment; s3: the shallow foundation pit in the common foundation pit is at the bottom, the layered and sectional excavation and support of the common foundation pit are continued, and the common foundation pit is at the bottom;
fourth, the site construction is carried out according to the construction scheme, and each procedure, construction parameters and the like are strictly carried out according to the requirements of the construction scheme.
The foundation pit layered and sectional excavation, support and support construction steps comprise:
r1: constructing a guard pile enclosure, leveling a site, electrically connecting in the presence of water, traffic untangling and pipeline migration and modification, and constructing a guard pile;
r2: constructing a crown beam and a retaining wall, constructing a ground drainage ditch, and carrying out layered excavation of a structural foundation pit after the condition of a fender pile reaches the design strength and a pipeline is ascertained, wherein the thickness of the layered excavation strictly complies with the requirement;
R3: and carrying out inter-pile net spray support immediately after the first layer of excavation is finished. When the earthwork is excavated to 500mm below the corresponding support, carrying out steel support construction;
R4: and (5) immediately carrying out inter-pile net spray support after the second layer of excavation is finished. And when the earthwork is excavated to 500mm below the corresponding support, carrying out steel support construction again.
When the steel support construction and the structure do not conflict, after the step R4, the steps of foundation pit layered and sectional excavation, support and support construction further comprise:
r5-1: the method comprises the steps of (1) in 30cm above a first foundation pit substrate, adopting manual excavation, constructing a drainage ditch in a pit after the foundation pit is excavated to the substrate, and supporting a steel pipe pile in the construction pit;
R6-1: immediately carrying out reinforcement mesh spray concrete support among piles after each layer of excavation is finished;
r7-1: digging to the position 30cm above the base of the second foundation pit, adopting manual digging, and carrying out final net spray concrete construction and base cushion construction after digging to the base;
R8-1: when the structure meets the design strength requirement, the support can be disassembled, and when the structure strength reaches 100% of backfill earthing.
When the steel support construction collides with the structure, after the R4 step, the steps of foundation pit layered and sectional excavation, support and support construction further comprise:
R5-2: within 30cm above the base of the first foundation pit, manually excavating, and constructing a steel pipe pile in the pit after excavating to the base;
r6-2: immediately carrying out reinforcement mesh spray concrete support among piles after each layer of excavation is finished;
r7-2: in 30cm above the second foundation pit substrate, manually excavating, and performing final net spray concrete construction and substrate cushion construction after excavating to the substrate;
r8-2: firstly constructing a structure which does not conflict with the optimized steel support design;
r9-2: after the construction of the main body structure which does not conflict with the steel support is completed and the strength of the top plate reaches the design strength, the second steel support can be disassembled, and another main body structure is constructed;
R10-2: and after the strength meets the requirements, backfilling the soil, and dismantling the steel support.
The drainage ditch is backfilled by broken stone.
The design strength is 80% of the strength of the top plate.
By adopting the technical scheme, compared with the prior art, the invention has the following beneficial effects:
(1) The cost is reduced, compared with the construction of the conventional method, the common foundation pit construction reduces the material consumption and labor cost required by the construction of the enclosure structure, and in the excavation process, the area of the foundation pit is increased, the construction of the follow-up procedures such as slag tapping and the like by adopting the conventional method is facilitated, the utilization rate of special machinery is reduced, and the cost is effectively reduced.
(2) The construction period is shortened, and mechanical operation is facilitated due to the increase of the width of the foundation pit; the reduction of the engineering quantity of the enclosure structure reduces the running water beat of each working procedure, shortens the running water step distance, accelerates the construction progress and shortens the total construction period.
(3) The resource is saved, and the protection or reinforcement of the enclosure structure is not needed any more due to the common foundation pit, so that the resource waste caused by the protection or reinforcement of the existing enclosure structure is reduced.
(4) The method has wide application range, and part of structural design cannot be located at the same elevation, so that the method particularly considers the common foundation pit excavation methods with different bottom elevations, and expands the application range of the method.
Drawings
Fig. 1 is a step diagram of layered and segmented excavation of a foundation pit and supporting construction when steel supporting construction and structure do not conflict.
Fig. 2 is a step diagram of layered and segmented excavation of a foundation pit and supporting construction when steel supporting construction collides with a structure.
FIG. 3 is a longitudinal section view of a two-structure foundation pit.
Fig. 4 is a longitudinal section view of the two-structure co-foundation pit after optimization.
In the figure:
1-a first foundation pit; 2-a second foundation pit; 3-steel support; 4-bottom elevation of the box culvert structure; 5-fold line.
Detailed Description
Embodiments of the present invention will be described below with reference to the accompanying drawings.
The method for excavating the foundation pit in the vicinity of the foundation pit with different bottom elevations comprises the following steps:
Firstly, determining an optimization scheme of an enclosure structure in advance according to the enclosure structure form of a common foundation pit section, wherein a first foundation pit 1 and a second foundation pit 2 are adjacent to the foundation pit, the two adjacent foundation pits 1 and 2 are prepared to be subjected to common foundation pit excavation, and the substrate elevation of the first foundation pit 1 is different from that of the second foundation pit 2; the excavation of the common foundation pit is as follows: the first foundation pit 1 and the second foundation pit 2 are close to each other, fender piles on the adjacent sides of the first foundation pit 1 and the second foundation pit 2 are shared piles, and the first foundation pit 1 and the second foundation pit 2 are combined into a large foundation pit;
Secondly, the optimized building envelope is communicated with a design, supervision and owners to perfect a new construction scheme before construction, and the building envelope construction is carried out after confirmation and optimization;
thirdly, determining excavation steps and construction parameters according to the optimized form of the enclosure structure;
The excavation step sequence of the common foundation pit is as follows:
S1: constructing an enclosure structure, evaluating a foundation pit excavation and supporting construction scheme, and determining excavation steps and construction parameters;
S2: foundation pit layered and sectional excavation, supporting and supporting construction, foundation pit detection, foundation pit deformation and safety assessment; the requirements on the layered excavation thickness of different foundation pits can be different, the requirements on the layered excavation depth of each foundation pit are met after the common foundation pit is used, and the minimum excavation layered excavation depth is used for ensuring safety. According to the elevation requirements of different structures in the common foundation pit, the excavation depth of each section in the common foundation pit is different, the foundation pit excavation segmentation is required to be complied with design and drawing requirements, the elevation difference of each structure is comprehensively considered, and the elevation difference can influence the construction of the support. If the first foundation pit is a structure with the constant substrate elevation, the second foundation pit is a structure with the gradually raised foundation pit elevation, and the second foundation pit substrate is lower than the first foundation pit substrate, or is level with the first foundation pit substrate, or is higher than the first foundation pit substrate. The second foundation pit steel supports two vertical channels, and the first foundation pit has two vertical channels and one vertical channel. The segmentation can be carried out according to the number of supporting channels and the drawing requirements, the two steel supports are divided into one segment, and the one and two steel supports are divided into one segment. As shown in FIG. 3, the contour line of the back structure is another passageway structure, the elevation relationship between the two structures is changed, and the number of passageway steel supporting channels is changed from two to one according to the shallowing of the passageway base. The elevation of the box culvert structure substrate elevation 4 is unchanged, the box culvert structure substrate elevation is always designed into two steel supports 3, and according to the rule of severe, two vertical steel supports 3 are adopted when the foundation pit is shared. As shown in fig. 4, the construction of a certain structure is necessarily affected by changing the steel support from one to two, and the structure is used for replacing the support after the construction of the unaffected structure is completed, and the other structure is constructed, so that the safety is ensured. The difference between the original design and the adjusted steel support is shown in fig. 3 and 4, so that the steel support can be segmented, the right side of the fold line 5, i.e. the position where the adjusted steel support design does not conflict with the original design, is taken as a section, and the left side of the fold line 5, i.e. the position where the adjusted steel support design conflicts with the original design, is taken as a section.
The foundation pit excavation mainly adopts a hydraulic breaking hammer and a long-arm excavator according to different geological conditions, the hydraulic breaking hammer breaks rocks and the slope is trimmed, the long-arm excavator carries out the dumping of earthwork and the pavement construction, the formulated layered sectional plan is strictly adhered to during excavation, the support is supported along with the excavation, and the support erection is also required to follow up in time according to design requirements. On the horizontal plane, after the section limit is marked according to the section length division, the long-arm excavator can firstly carry out soil raking operation to enable hard rock to leak out, then the hydraulic breaking hammer is used for breaking rock and soil, the excavator is used for pile-up and transportation after breaking the broken rock and soil into small blocks, and when the rock strength in the pit is too high and the hydraulic breaking hammer is under work efficiency, static blasting or differential blasting can be considered. And building a temporary pavement between the current construction section and the next construction section for mechanical running. Thus, the excavation is started from the circulation to the horizontal plane. On the vertical plane, according to the division of the layering thickness, the construction process is the same as that of the horizontal plane, after the construction circulation of the long-arm excavator and the hydraulic breaking hammer, the slag is transported by a slag car through a pavement, the construction surface is cleaned, and the next layer of excavation is carried out. When the elevation of the two structures in the common foundation pit is different, the excavation must be that the shallower structure is firstly seen at the bottom, at this time, according to the construction design, whether the support in the pit is needed or not, if the support in the pit is needed, the next stage of excavation is carried out after the support construction in the pit is finished. When the foundation pit with the temporary horse road can not be built by placing slopes at two ends is encountered, the last muck can be vertically lifted and operated by the grab bucket, and the muck needs to be fully broken by the breaking hammer before operation so as to facilitate the construction of the grab bucket, and the machinery in the pit can be lifted out by the machinery such as an automobile crane or a crawler crane. When the lifting weight is too large or the danger is high, special safety construction scheme programming is needed.
The support construction design is according to foundation ditch excavation degree of depth, because the foundation ditch construction altogether, can be the step form according to the different elevations of each structure in the foundation ditch and distribute, original support design no longer is suitable for. For example, the first foundation pit is shallower, designed as a steel support; the second foundation pit is deeper and is designed into two steel supports, and in the common foundation pit section, the steel support forms are unified due to the unification of the foundation pit, and at the moment, construction is performed according to the design that the number of steel supports is more. When the depth of the first foundation pit is shallower, two vertical steel supports designed by the second foundation pit are still adopted, the second foundation pit with larger depth is constructed in advance, after the construction of the second foundation pit is completed and the strength reaches the design requirement, the structure of the second foundation pit can be used for replacing the support, the second steel supports are removed, and then the construction of the first foundation pit can be performed. When various parameters such as support model, diameter, interval and the like adopted by each original foundation pit conflict, the large model and the small interval are compared to be used as the support construction parameters of the common foundation pit. When other models are adopted, corresponding checking calculation should be carried out.
After the foundation pit is shared, the influence on the supporting structure is only the reduction of engineering quantity, the supporting structure form is not changed, and the side walls of the original foundation pit are respectively supported by adopting the original design.
The foundation pit monitoring is used as an important safety guarantee measure for foundation pit excavation, and when a common foundation pit construction is adopted, stricter numerical requirements in original foundation pit monitoring requirements are adopted for monitoring. When the required specifications of the foundation pit of the original structure are different, the monitoring items and the reference standard are included. To ensure construction safety.
S3: and (3) the shallow foundation pits in the common foundation pit are at the bottom, the layered and sectional excavation and support of the common foundation pit are continued, and the common foundation pit is at the bottom entirely. The shallow foundation pit in the common foundation pit is at the bottom, after the common foundation pit is excavated, according to the design elevations of different structures, the foundation pit is in step-shaped distribution after being excavated on site, the foundation pit with larger design elevation is at the bottom firstly, and after the shallow foundation pit is designed to be at the bottom, according to the height difference between the foundation pit and the deep foundation pit, the engineering geology and hydrogeology conditions, the support and drainage in the foundation pit are considered. The steel pipe piles and the support mode of concrete pouring are adopted in the foundation pit, stability of the substrate in the foundation pit is protected, and meanwhile the edge line of the structure in the foundation pit is guaranteed. And continuing to perform layering, sectionalized excavation and supporting, and if the construction of the steel pipe pile is determined according to the geological conditions in the foundation pit, performing the construction of the steel pipe pile before the excavation of the deeper foundation pit after the shallow foundation pit is seen at the bottom. After the shallow structure foundation pit in the common foundation pit is at the bottom, the other deep structure foundation pit is continuously excavated downwards, and the steps can temporarily leave the catwalk, so that the mechanical transfer is facilitated. The deeper foundation pit excavation should also strictly follow the layered thickness requirements, and the supporting structure construction must follow the foundation pit excavation.
Fourth, the site construction is carried out according to the construction scheme, and each procedure, construction parameters and the like are strictly carried out according to the requirements of the construction scheme. And after all structures in the common foundation pit are at the bottom, checking and accepting the substrate and pouring the cushion layer. If the bottom cannot be seen completely within 12 hours, the bottom-seen part should be poured in advance, and a road through which the machine passes is reserved, so that the cushion layer is prevented from being damaged mechanically.
As shown in fig. 1, when the steel support construction and the structure do not conflict, the foundation pit layered and sectional excavation and the support and support construction comprises the following steps:
r1: constructing a guard pile enclosure, leveling a site, electrically connecting in the presence of water, traffic untangling and pipeline migration and modification, and constructing a guard pile;
r2: constructing a crown beam and a retaining wall, constructing a ground drainage ditch, and carrying out layered excavation of a structural foundation pit after the condition of a fender pile reaches the design strength and a pipeline is ascertained, wherein the thickness of the layered excavation strictly complies with the requirement;
R3: and carrying out inter-pile net spray support immediately after the first layer of excavation is finished. When the earthwork is excavated to 500mm below the corresponding support, carrying out steel support construction;
R4: and (5) immediately carrying out inter-pile net spray support after the second layer of excavation is finished. When the earthwork is excavated to 500mm below the corresponding support, carrying out steel support construction again;
R5-1: the method comprises the steps of (1) in 30cm above a substrate of a first foundation pit 1, adopting manual excavation, constructing a drainage ditch in the pit after the foundation pit is excavated to the substrate, and supporting a steel pipe pile in the construction pit;
R6-1: immediately carrying out reinforcement mesh spray concrete support among piles after each layer of excavation is finished;
R7-1: digging to the position 30cm above the substrate of the second foundation pit 2, adopting artificial digging, and carrying out final net spray concrete construction and substrate cushion construction after digging to the substrate;
R8-1: when the structure meets the design strength requirement, the support can be disassembled, and when the structure strength reaches 100% of backfill earthing.
As shown in fig. 2, when steel support construction collides with a structure, the foundation pit is excavated in a layered and segmented manner, and the support and support construction steps are as follows:
r1: constructing a guard pile enclosure, leveling a site, electrically connecting in the presence of water, traffic untangling and pipeline migration and modification, and constructing a guard pile;
r2: constructing a crown beam and a retaining wall, constructing a ground drainage ditch, and carrying out layered excavation of a structural foundation pit after the condition of a fender pile reaches the design strength and a pipeline is ascertained, wherein the thickness of the layered excavation strictly complies with the requirement;
R3: and carrying out inter-pile net spray support immediately after the first layer of excavation is finished. When the earthwork is excavated to 500mm below the corresponding support, carrying out steel support construction;
R4: and (5) immediately carrying out inter-pile net spray support after the second layer of excavation is finished. When the earthwork is excavated to 500mm below the corresponding support, carrying out steel support construction again;
r5: within 30cm above the base of the first foundation pit 1, manually excavating, and constructing a steel pipe pile in the pit after excavating to the base;
R6: immediately carrying out reinforcement mesh spray concrete support among piles after each layer of excavation is finished;
R7: in 30cm above the substrate of the second foundation pit 2, manually excavating, and performing final net spray concrete construction and substrate cushion construction after excavating to the substrate;
R8: firstly constructing a structure which does not conflict with the optimized steel support design;
R9: after the construction of the main body structure which does not conflict with the steel support is completed and the strength of the top plate reaches the design strength, the second steel support can be disassembled, and another main body structure is constructed;
R10: and after the strength meets the requirements, backfilling the soil, and dismantling the steel support.
The embodiments described in this specification are merely examples of implementations of the inventive concept. The scope of the present invention should not be construed as being limited to the specific forms set forth in the examples, but the scope of the present invention and the equivalent means as will occur to those skilled in the art based on the inventive concept.
Claims (5)
1. The method for excavating the foundation pit in the vicinity of the foundation pit with different bottom elevations is characterized by comprising the following steps of:
Firstly, determining an optimization scheme of an enclosure structure in advance according to an enclosure structure form of a common foundation pit section, wherein a first foundation pit (1) and a second foundation pit (2) are adjacent to the foundation pit, the two adjacent foundation pits are prepared to be subjected to common foundation pit excavation, and substrate elevations of the first foundation pit (1) and the second foundation pit (2) are different; the excavation of the common foundation pit is as follows: the guard piles on the adjacent sides of the first foundation pit (1) and the second foundation pit (2) are shared piles, and the first foundation pit (1) and the second foundation pit (2) are combined into a large foundation pit;
Secondly, the optimized building envelope is communicated with a design, supervision and owners to perfect a new construction scheme before construction, and the building envelope construction is carried out after confirmation and optimization;
Thirdly, determining excavation steps and construction parameters according to the optimized form of the enclosure structure; the excavation step sequence of the common foundation pit is as follows:
S1: constructing an enclosure structure, evaluating a foundation pit excavation and supporting construction scheme, and determining excavation steps and construction parameters;
S2: foundation pit layered and sectional excavation, supporting and supporting construction, foundation pit detection, foundation pit deformation and safety assessment; when the requirements on different foundation pit layered excavation thicknesses are different, the minimum excavation layered excavation depth is adopted to ensure safety;
s3: the shallow foundation pit in the common foundation pit is at the bottom, the layered and sectional excavation and support of the common foundation pit are continued, and the common foundation pit is at the bottom;
fourthly, performing site construction according to a construction scheme, wherein each procedure and construction parameters are strictly performed according to the requirements of the construction scheme;
the foundation pit layered and sectional excavation, supporting and supporting construction steps comprise:
r1: constructing a guard pile enclosure, leveling a site, electrically connecting in the presence of water, traffic untangling and pipeline migration and modification, and constructing a guard pile;
r2: constructing a crown beam and a retaining wall, constructing a ground drainage ditch, and carrying out layered excavation of a structural foundation pit after the condition of a fender pile reaches the design strength and a pipeline is ascertained, wherein the thickness of the layered excavation strictly complies with the requirement;
R3: immediately carrying out inter-pile net spray supporting after the first layer of excavation is finished, and carrying out steel supporting construction when earthwork is excavated to 500mm below the corresponding supporting;
r4: and immediately carrying out inter-pile net spray support after the second layer of excavation is finished, and carrying out steel support construction again when the earthwork is excavated to 500mm below the corresponding support.
2. The method for excavating foundation pit in close proximity to foundation pit with different bottom elevations according to claim 1, wherein when the steel support construction and the structure do not conflict, after the R4 step, the steps of excavating the foundation pit in a layered and segmented manner and supporting construction further comprise:
r5-1: the method comprises the steps of (1) in 30cm above a substrate of a first foundation pit, adopting artificial excavation, constructing a drainage ditch in the pit after the foundation pit is excavated to the substrate, and supporting a steel pipe pile in the construction pit;
R6-1: immediately carrying out reinforcement mesh spray concrete support among piles after each layer of excavation is finished;
r7-1: digging to the position 30cm above the substrate of the second foundation pit (2), adopting manual digging, and carrying out final net spray concrete construction and substrate cushion construction after digging to the substrate;
r8-1: and when the structure meets the design strength requirement, the support is disassembled, and when the structural strength reaches 100% of backfill covering soil.
3. The method for excavating foundation pit in close proximity to foundation pit with different bottom elevations according to claim 1, wherein when the steel support construction collides with the structure, the step of excavating the foundation pit in a layered and segmented manner and the step of supporting and supporting construction further comprises:
r5-2: within 30cm above the substrate of the first foundation pit (1), manually excavating, and constructing a steel pipe pile in the pit after excavating to the substrate;
r6-2: immediately carrying out reinforcement mesh spray concrete support among piles after each layer of excavation is finished;
r7-2: in 30cm above the substrate of the second foundation pit (2), manually excavating, and after excavating to the substrate, carrying out final net spray concrete construction and substrate cushion construction;
r8-2: firstly constructing a structure which does not conflict with the optimized steel support design;
R9-2: after the construction of the main body structure which does not conflict with the steel support is completed and the strength of the top plate reaches the design strength, the second steel support is disassembled, and another main body structure is constructed;
R10-2: and after the strength meets the requirements, backfilling the soil, and dismantling the steel support.
4. A method for excavating a common foundation pit adjacent to a foundation pit with different bottom elevations according to claim 2 or 3, wherein:
The drainage ditch is backfilled by broken stone.
5. A method for excavating a common foundation pit adjacent to a foundation pit with different bottom elevations according to claim 2 or 3, wherein:
the design strength is 80% of the strength of the top plate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210938569.7A CN115125960B (en) | 2022-08-05 | 2022-08-05 | Common foundation pit excavation method for foundation pits with different bottom elevations and close to each other |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210938569.7A CN115125960B (en) | 2022-08-05 | 2022-08-05 | Common foundation pit excavation method for foundation pits with different bottom elevations and close to each other |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115125960A CN115125960A (en) | 2022-09-30 |
| CN115125960B true CN115125960B (en) | 2024-06-25 |
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| CN107313431A (en) * | 2017-08-02 | 2017-11-03 | 中铁隧道集团二处有限公司 | Close on not contour foundation ditch method for synchronously constructing |
| CN108914941A (en) * | 2018-08-15 | 2018-11-30 | 北京市政建设集团有限责任公司 | A kind of station pit earthwork digging one step process |
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| CN103114592B (en) * | 2011-11-16 | 2014-11-19 | 龙信建设集团有限公司 | Method for deep excavation pit combination support construction close to subway station |
| US10138616B2 (en) * | 2016-08-12 | 2018-11-27 | Wuhan Zhihe Geotechnical Engineering Co., Ltd. | Inverse construction method for deep, large and long pit assembling structure of suspension-type envelope enclosure |
| CN110528531A (en) * | 2019-07-31 | 2019-12-03 | 浙江杭海城际铁路有限公司 | A method of it utilizes and does close to foundation pit enclosure stake to excavation pit fender post |
| CN110409454A (en) * | 2019-08-07 | 2019-11-05 | 上海建工二建集团有限公司 | Open type foundation pit block construction system and method |
| CN113216205A (en) * | 2021-05-08 | 2021-08-06 | 中国建筑第四工程局有限公司 | Partition wall support conversion method in deep foundation pit and foundation pit dividing construction |
| CN113550322A (en) * | 2021-07-09 | 2021-10-26 | 上海市基础工程集团有限公司 | Enclosure system next to deep and shallow foundation pit and construction method |
| CN114277844B (en) * | 2022-01-24 | 2023-07-25 | 中国建筑第八工程局有限公司 | Construction method of underground structure |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN107313431A (en) * | 2017-08-02 | 2017-11-03 | 中铁隧道集团二处有限公司 | Close on not contour foundation ditch method for synchronously constructing |
| CN108914941A (en) * | 2018-08-15 | 2018-11-30 | 北京市政建设集团有限责任公司 | A kind of station pit earthwork digging one step process |
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