CN112554198B - Construction method of deep foundation pit protection structure adjacent to high-rise building - Google Patents
Construction method of deep foundation pit protection structure adjacent to high-rise building Download PDFInfo
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- CN112554198B CN112554198B CN202011220415.1A CN202011220415A CN112554198B CN 112554198 B CN112554198 B CN 112554198B CN 202011220415 A CN202011220415 A CN 202011220415A CN 112554198 B CN112554198 B CN 112554198B
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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
- E02D29/00—Independent underground or underwater structures; Retaining walls
- E02D29/045—Underground structures, e.g. tunnels or galleries, built in the open air or by methods involving disturbance of the ground surface all along the location line; Methods of making them
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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
- E02D5/24—Prefabricated piles
- E02D5/28—Prefabricated piles made of steel or other metals
- E02D5/285—Prefabricated piles made of steel or other metals tubular, e.g. prefabricated from sheet pile elements
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D2250/00—Production methods
- E02D2250/003—Injection of material
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D2300/00—Materials
- E02D2300/0004—Synthetics
- E02D2300/0018—Cement used as binder
- E02D2300/002—Concrete
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D2300/00—Materials
- E02D2300/0004—Synthetics
- E02D2300/0018—Cement used as binder
- E02D2300/0023—Slurry
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D2300/00—Materials
- E02D2300/0026—Metals
- E02D2300/0029—Steel; Iron
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- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
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Abstract
The invention discloses a construction method of a deep foundation pit protection structure adjacent to a high-rise building, which comprises the following steps of S1, construction of a small-diameter steel pipe pile: before the deep foundation pit is excavated, constructing a small-diameter steel pipe pile between a building foundation and a support structure on the outer side of the foundation pit; s2, construction of the pile top crown beam: constructing a pile top crown beam on the top of the small-diameter steel pipe pile, and constraining the single-pile small-diameter steel pipe pile into an integral stress structure; s3, constructing the foundation reinforcing pile: drilling holes at the bottom of the building under the building at an oblique angle of 30-60 degrees between the small-diameter steel pipe pile and the building to avoid the building foundation, then injecting casing materials into the drilled holes, then lowering sleeve valve pipes, and finally performing static pressure grouting construction; s4, constructing the concrete-filled steel tubular column; s5, constructing a structural slab; and S6, constructing a support system. The method can improve the supporting capability of the deep foundation pit, can effectively ensure the safety of a high-rise building laterally leaning against the foundation pit enclosure wall, and can prevent the problems of structural deformation, cracks, even collapse of the building and the like caused by settlement of the high-rise building.
Description
Technical Field
The invention relates to the technical field of foundation reinforcement of a side-by-side deep foundation pit building, in particular to a construction method of a deep foundation pit protection structure adjacent to a high-rise building.
Background
With the continuous acceleration of urbanization process in China, deep foundation pit engineering in cities is increasing day by day. The project that a newly-built deep foundation pit is close to a high-rise building is gradually increased, dynamic interaction is inevitably generated between the deep foundation pit and the building in the construction process, and when the existing enclosure structure is difficult to meet the side pressure requirement of the surrounding building due to climate, geology, time effect and the like of the deep foundation pit, the building is settled, the structural deformation and cracks are caused, and even the building collapses and the like.
Disclosure of Invention
Aiming at the problems, the invention provides a construction method of a deep foundation pit protection structure adjacent to a high-rise building, which can improve the supporting capability of the deep foundation pit and effectively ensure the safety of the high-rise building laterally leaning against a foundation pit enclosure wall so as to prevent the high-rise building from settling, causing structural deformation and cracks, even collapsing the building and the like.
In order to achieve the above object, the present invention provides the following technical solutions.
The construction method of the deep foundation pit protection structure adjacent to the high-rise building is characterized by comprising the following steps of:
s1 construction of small-diameter steel pipe pile
Before the deep foundation pit is excavated, constructing a small-diameter steel pipe pile between a building foundation and a support structure on the outer side of the foundation pit;
s2 construction of pile top crown beam
Constructing a pile top crown beam at the top of the small-diameter steel pipe pile, and constraining the single-pile small-diameter steel pipe pile into an integral stress structure, so that the single-pile stress is converted into pile group stress when the small-diameter steel pipe pile is subjected to lateral force; when the small-diameter steel pipe pile is subjected to lateral force, the pile top crown beam and the pile top bedrock section respectively play a role of a support, so that a cantilever structure is changed into a simply supported structure, the shearing resistance of a pile body is greatly improved, and the lateral sliding resistance of the pile body is further improved;
s3 construction of foundation reinforcing pile
The method comprises the following steps of constructing a foundation reinforcing pile by adopting a sleeve valve pipe compensation grouting process, namely drilling a hole between a small-diameter steel pipe pile and a building at the bottom of the building at an oblique angle of 30-60 degrees towards the position right below the building to avoid the building foundation, reducing disturbance to an original soil body at the bottom of the foundation, avoiding the change of a stress stable state of the soil body and the overlarge strength loss, further influencing the bearing capacity of the building foundation, injecting casing materials into a drilled hole, then lowering a sleeve valve pipe, and finally performing static pressure grouting construction, improving the soil body performance, improving the soil body strength and further improving the bearing capacity of the building foundation;
s4 construction of concrete filled steel tubular column
Constructing a steel pipe concrete column at the center of the deep foundation pit, anchoring the steel pipe concrete column into bedrock to ensure the vertical bearing capacity of a single pile, providing a support and vertical supporting force for the structural slab, reducing the span of the structural slab and improving the stability of the structural slab; the steel pipe concrete column consists of a permanent pile and a temporary steel pipe column anchored in the permanent pile; the length of the temporary steel pipe column anchored into the permanent pile is not less than 4 m, a stud is arranged on the outer wall of the anchoring section of the temporary steel pipe column to improve anchoring force and enhance anchoring effect, and a water-permeable and easily-compact material is filled around the temporary steel pipe column;
s5, construction of structural slab
The construction method comprises the following steps of constructing a structural slab at the top of the deep foundation pit, playing a role of a plurality of horizontal supports, providing a great horizontal supporting force for the enclosure structure, improving the lateral deformation resistance of the enclosure structure in the foundation pit, and connecting the steel pipe concrete column with the enclosure structure, the lattice column and the supporting system in the deep foundation pit to form a whole;
s6 construction of support system
The concrete support is constructed in a layered mode in the deep foundation pit, and the cross braces and the connecting beams are arranged between the steel pipe concrete columns and the lattice columns, so that the independent supporting structures form a supporting system, and the deformation resistance of the supporting system is greatly improved.
As a specific technical scheme, in the step S1, in the construction of the small-diameter steel pipe pile, the small-diameter steel pipe pile adopts a construction process of subsection, row jump and interval pile jump; the distance between the outer side of the small-diameter steel pipe pile and the building enclosure structure on the outer side of the deep foundation pit is not less than 50 cm, so that the integrity of a flexible soil body between the rigid small-diameter steel pipe pile and the rigid building enclosure structure is guaranteed, disturbance generated during foundation pit excavation is buffered to a certain extent when passing through the flexible soil body, the interference to a building foundation is reduced, and settlement is reduced; meanwhile, the flexible soil body has plasticity, when the soil body in the foundation pit is unloaded, the enclosure structure is deformed by the lateral force generated by a building outside the foundation pit and the soil pressure outside the foundation pit, the deformation of the foundation pit can be reduced by the existence of the flexible soil body and the plasticity of the flexible soil body, and after the strength of the inner support of the foundation pit reaches a design value, the deformation of the enclosure structure can be traced back to a certain range, so that the inner support system of the foundation pit is further stabilized; the length of the small-diameter steel pipe pile anchored into the foundation pit is not less than 1 m; the pile spacing and the row spacing of the small-diameter steel pipe pile are 2-3 times of the diameter of the pile, and quincunx arrangement is adopted to ensure anchoring force and pile body stability.
In the step S1, in the construction of the small-diameter steel pipe pile, quincunx grouting holes are arranged in an anchoring section 2-5 m away from the bottom of the small-diameter steel pipe pile, cement-water glass double grout is selected as the grout, the grout calculates the diffusion radius and the pile spacing, and multiple-time spacing is adopted for grouting.
Specifically, in the step S1, in the construction of the small-diameter steel pipe pile, the diameter d of the steel pipe used in the small-diameter steel pipe pile is not less than 95 mm and not more than 127 mm, and the wall thickness of the steel pipe used is not less than 8 mm.
As a specific technical solution, in the step S1 of constructing the small-diameter steel pipe piles, when the depth of the deep foundation pit exceeds 20 m, the number of rows of the small-diameter steel pipe piles is not less than 3, and when the depth of the deep foundation pit is less than 20 m, the number of rows of the small-diameter steel pipe piles is not less than 2.
As a specific technical scheme, in the step S2, in the construction of the pile top crown beam, an L-shaped steel bar is welded on the upper and lower single faces of the outer wall of a steel pipe in a small-diameter steel pipe pile, and the L-shaped steel bar is welded in contact with a main bar of the pile top crown beam to ensure effective connection and stable stress between the steel pipe pile and the crown beam, the pile top crown beam and the constructed crown beam in the deep foundation pit have the same height and the same thickness, and the pile top crown beam and the constructed crown beam are connected into a whole through bar planting to improve the lateral force resistance; meanwhile, the steel pipe top in the small-diameter steel pipe pile is controlled to be exposed out of the beam surface of the pile top crown beam by 50-100 mm, and secondary pouring can be facilitated.
As a specific technical scheme, in the step S3 of constructing the foundation reinforcing pile, the initial position of the drill hole is not less than 1 m and not more than 2 m away from the building.
As a specific technical scheme, in the step S4, in the construction of the concrete filled steel tubular column, the diameter of the permanent pile is larger than or equal to that of the enclosure wall or the pile in the enclosure structure, and the anchoring depth and the concrete mark of the base of the permanent pile are the same as those of the enclosure wall or the pile in the enclosure structure; the diameter of the temporary steel pipe column is more than or equal to 600 mm and less than or equal to 800mm, underwater concrete is poured into the steel pipe, and the mark is the same as that of a surrounding wall or a pile in the surrounding structure.
As a specific technical scheme, in the step S5, when the length of the deep foundation pit adjacent to the building is greater than 54 m, the structural slab is constructed by a skip method, a skip part of the structural slab is constructed by a forward construction method, the other parts of the structural slab are constructed by a reverse construction method, and a hidden beam is additionally arranged in the structural slab constructed by the reverse construction method to wrap and connect the concrete-filled steel tube column and the lattice column.
As a specific technical scheme, in the step S6, I-shaped steel is adopted as the shear braces in the construction of the support system.
The invention has the beneficial effects that:
aiming at the condition that micro-settlement occurs close to a building in the construction process of a deep foundation pit, the invention adopts the small-diameter steel pipe pile and the foundation reinforcing pile to reinforce the soil body around the building foundation, improves the overall strength, combines the reverse construction of the inner top plate of the foundation pit and a multiple supporting system, improves the supporting capability in the foundation pit, reduces the settlement of the building, prevents cracking and inclination, saves the construction cost, is green and environment-friendly, occupies small space, improves the excavation efficiency of the deep foundation pit, and effectively ensures the safety of the building.
Drawings
FIG. 1 is a schematic illustration of the construction of the protective structure of the present invention;
FIG. 2 is a connection diagram of a concrete filled steel tube column and a lattice column in the protective structure of the present invention;
FIG. 3 is an enlarged schematic view at A in FIG. 1;
the meanings of the marks in the above figures are as follows: 1-small-diameter steel pipe pile, 2-pile top crown beam, 3-foundation reinforcement pile, 4-steel pipe concrete column, 401-permanent pile, 402-temporary steel pipe column, 5-structural plate, 6-concrete support, 7-crown beam, 8-enclosure structure, 9-lattice column, 10-building foundation, 11-deep foundation pit, 12-building, 13-shear support and 14-connecting beam.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Examples
Referring to fig. 1 to 3, a method for constructing a deep foundation pit protection structure adjacent to a high-rise building includes the steps of:
s1 construction of small-diameter steel pipe pile
Before the excavation of the deep foundation pit, a small-diameter steel pipe pile 1 is constructed between a building foundation 10 and a support structure 8 on the outer side of the foundation pit, and the method specifically comprises the following steps:
1) carrying out site cleaning, pipeline investigation, building an operation platform and measuring the position of a pile position;
2) drill in-place pore-forming and pore-cleaning in hole
Wherein, the drilling machine is connected with a drill rod once every 2 m of footage, and bentonite slurry is adopted to protect the wall, so as to prevent hole collapse; the distance between the outer side of the small-diameter steel pipe pile 1 and the enclosure structure is not less than 50 cm, so that the integrity of a flexible soil body is guaranteed, and the disturbance of foundation pit excavation on a building foundation is reduced;
3) hoisting steel pipe pile
When the depth of the foundation pit exceeds 20 m, the number of rows of the small-diameter steel pipe piles is not less than 3, and when the depth of the foundation pit is less than 20 m, the number of rows of the small-diameter steel pipe piles is not less than 2; the small-diameter steel pipe pile adopts the technology of 'segmenting, jumping rows and jumping piles at intervals'; the diameter d of the steel pipe is more than or equal to 95 mm and less than or equal to 127 mm, and the wall thickness is not less than 8 mm; the pile spacing and the row spacing of the small-diameter steel pipe piles are 2.5 times of the diameter d of the piles, and the small-diameter steel pipe piles are arranged in a quincunx manner; the length of the small-diameter steel pipe pile anchored into the bottom of the adjacent foundation pit is not less than 1 m, so that the anchoring force and the stability of a pile body are ensured; arranging grouting holes in a quincunx shape at an anchoring section of 2-5 m of the bottom of the small-diameter steel pipe pile, selecting cement-water glass double grout as the grout, and calculating the diffusion radius of the grout and the distance between piles;
4) pouring double slurry to the upper opening for turning slurry
The top surface of the small-diameter steel pipe pile, which is exposed out of the top surface of the pile top crown beam 2, is 50-100 mm, so that a grouting pipe can be connected conveniently; grouting pressure is 0.6-1.0 Mpa, diffusion radius is 0.25 m, and water-cement ratio is controlled between 0.6: 1-1: 1; grouting is carried out in a multi-time interval mode, the average time is 3-5 times, and the standard of finishing grouting is pipe top slurry leakage;
s2 construction of pile top crown beam
Constructing a pile top crown beam 2 at the top of the small-diameter steel pipe pile 1, and constraining the single-pile small-diameter steel pipe pile 1 into an integral stress structure, and specifically comprises the following steps:
1) survey lofting
2) Pile head for manually removing steel pipe pile
Before the construction of the pile top crown beam, pile head removing operation can be carried out when the strength of cement paste in the small-diameter steel pipe pile 1 reaches more than 30 Mpa, and the steel pipe top of the small-diameter steel pipe pile 1 is controlled to be exposed out of the top surface of the pile top crown beam 2 by 50-100 mm for later-stage secondary grouting;
3) pouring concrete cushion layer
4) Masonry brick moulding bed
5) Plastering with cement mortar
6) Binding of reinforcing steel bars
L-shaped steel bars are welded on the upper and lower surfaces of the outer wall of a steel pipe in the small-diameter steel pipe pile 1, and the L-shaped steel bars are welded in contact with main bars of a pile top crown beam 2, so that the effective connection and the stable stress of the steel pipe pile and the crown beam are ensured;
7) pouring of concrete
The pile top crown beam 2 and the crown beam 7 are controlled to have the same elevation and the same thickness and are connected into a whole through embedded steel bars so as to improve the lateral force resistance;
8) maintaining
S3 construction of foundation reinforcing pile
Adopt sleeve valve pipe compensation slip casting technology construction ground reinforcing pile 3, between minor diameter steel-pipe pile 1 and building 12 promptly, at the bottom of building 12 with slant angle 30 ~60 towards building 12 under the drilling to avoid building basis 10, later pour into the cover shell material in the drilling, lower sleeve valve pipe again, carry out the static pressure slip casting construction at last, specifically include the following step:
1) measuring the hole position
Wherein the initial position of the drill hole is not less than 1 m and not more than 2 m away from the building 12;
2) drill in place
3) Oblique hole forming
Constructing 5 rows of phi 50-sleeve valve pipes between the small-diameter steel pipe pile 1 and the building 12, wherein the interval is 1.0 m, the row spacing is 0.5 m, the valve pipes are arranged in a quincunx manner, and the grouting pipes are PVC pipes drilled with grout outlet holes with the diameter of 6 mm; after the hole position is determined, the drilling machine enters the field and is in place, and holes are drilled at the bottom of the building 12 towards the position right below the building 12 at an oblique angle of 30-60 degrees so as to avoid the building foundation 10;
4) injecting jacket shell material
The water-cement ratio of the slurry is 1:1, and the grouting range is 1 m below the residual sandy cohesive soil (hard plastic); after the casing material replaces the mud in the hole, the casing material is immediately inserted into the sleeve valve pipe, and the upper part of the casing material is 20 cm higher than the ground; curing the shell material for 5-7 days, and grouting after the strength reaches 0.3-0.5 MPa;
5) down-sleeve valve pipe
6) Grouting
S4 construction of concrete filled steel tubular column
The method is characterized in that the concrete-filled steel tubular column 4 is constructed in the center of the deep foundation pit 11, and the method specifically comprises the following steps:
1) pile position lofting
The longitudinal spacing of the steel pipe concrete columns 4 is equal to the supporting spacing of foundation pit concrete, and the steel pipe concrete columns 4 are arranged at the central position (the position of one-half of the width of the foundation pit) of the deep foundation pit 11 so as to provide a support and vertical supporting force for the structural slab, reduce the span of the structural slab and improve the stability of the structural slab;
2) embedding a pile casing;
measuring the pile position by using a total station, excavating a pile casing hole, and adopting a steel pile casing with the diameter of more than 1.5 m;
3) drill in-place drilling
4) Cleaning the hole after the hole is formed
5) Inspection of pore formation
6) Drill shifting
7) Hoisting steel pipe column
The aperture needs to be rechecked before hoisting, the pile position tolerance deviation is not more than 50 mm, and the pile body verticality deviation is not more than 1/300; the steel pipe concrete column 4 consists of a permanent pile and a temporary steel pipe column anchored in the permanent pile; the diameter of the permanent pile is more than or equal to that of a surrounding wall or a pile in the enclosure structure 8, the anchoring depth and the concrete grade of the base of the permanent pile are the same as those of the surrounding wall or the pile in the enclosure structure 8, the anchoring length of the temporary steel pipe column into the permanent pile is not less than 4 m, the outer wall of the anchoring section of the temporary steel pipe column is provided with studs, the length of the studs is 100 mm, the distance between the studs is 150 mm, and each section is not less than 12;
8) down-placing conduit
9) Pouring concrete
Pouring underwater concrete, and marking the same number as the enclosure wall or pile in the enclosure structure 8;
10) removal of a catheter
11) Initial setting of pile foundation for fixing steel pipe column
12) Cast-in-place steel pipe column concrete
A hidden beam is additionally arranged on the structural slab to connect the lattice column and the steel pipe concrete column; the steel tube concrete column and the hidden beam bottom main rib are connected by adopting an annular rigid plate, the steel reinforcement cage is connected with the steel tube concrete column and the hidden beam top main rib, the steel reinforcement cage is inserted into the steel tube concrete column and is not less than 1200 mm, and the anchoring length of the steel reinforcement cage and the hidden beam top main rib is not less than 400 mm; filling permeable and easily-compacted materials such as gravel, sand and the like around the pile of the temporary steel pipe column;
s5, construction of structural slab
The construction method comprises the following steps of constructing a structural slab 5 at the top of the deep foundation pit 11 to connect the steel pipe concrete column 4 with an enclosure structure 8, a lattice column 9 and a support system in the deep foundation pit 11 to form a whole, and specifically comprising the following steps:
1) excavating earth to the bottom of the top plate
2) Chiseling diaphragm wall
Before construction, chiseling part of enclosure walls or piles, wherein the depth is 300 mm, and the height is equal to the thickness of a structural plate; when chiseling, I-shaped steel at the joint is reserved, concrete in the I-shaped steel is removed completely, and L-shaped steel bars and the I-shaped steel are welded on two sides;
3) bar planting
Chiseling off the underground diaphragm wall part for bar planting construction, adopting an electric hammer to form a hole, and drilling the hole with the aperture d + 4-8 mm (d is the diameter of a steel bar); two rows of anchoring ribs are implanted into the enclosure wall or the pile from top to bottom, the diameter of each anchoring rib is the same as that of a transverse main rib of the structural slab, the length of each anchoring rib is not less than 300 mm, and the anchoring ribs are connected with the main ribs of the structural slab in a single-sided welding manner; the reinforcing steel bar planting in the horizontal hole is carried out by tamping the glue in the hole by using a phi 6 thin reinforcing steel bar matched with a glue supporting plate (a clean wood plate), and the reinforcing steel bar is driven into the hole by adopting a rotating or hand hammer striking mode;
4) excavated downward turning beam and side wall groove
5) Pouring concrete cushion layer
6) Brick mould for building downward turning beam and side wall
The length of a single structural slab is not less than 18 m and not more than 25 m, the number of the structural slabs is set according to the length of the deep foundation pit 11 adjacent to the building, and when the length of the deep foundation pit 11 adjacent to the building is more than 54 m, the structural slab is constructed by adopting a hop method, the hop part of the structural slab is constructed by adopting a forward construction method, the other part of the structural slab is constructed by adopting a reverse construction method, and a hidden beam is additionally arranged in the structural slab constructed by the reverse construction method, wraps and connects the steel pipe concrete column 4 and the lattice column 9;
7) waterproof construction
Grouting pipes are respectively embedded up and down at the positions where the top plate penetrates into the enclosure structures at two sides by 300 mm and the height is 800mm, and a cement-based permeable crystalline waterproof material is applied to the part in contact with the enclosure structures; the full-section pre-buried steel plate water stop belts of the structural plates and the side walls, the grouting pipes capable of grouting the brand-new sections and the steel bar connectors;
8) binding top plate steel bar
9) Mounting end die
10) Pouring concrete
11) Maintaining
S6 construction of support system
And (3) constructing a concrete support 6 in the deep foundation pit 11 in a layering manner, and arranging a cross brace 13 and a connecting beam 14 between the steel pipe concrete column 4 and the lattice column 9 to enable the independent support structure to form a support system.
Claims (10)
1. The construction method of the deep foundation pit protection structure adjacent to the high-rise building is characterized by comprising the following steps of:
s1 construction of small-diameter steel pipe pile
Before the deep foundation pit is excavated, constructing a small-diameter steel pipe pile (1) between a building foundation (10) and a building enclosure structure (8) on the outer side of the foundation pit; the distance between the outer side of the small-diameter steel pipe pile (1) and the enclosure structure (8) on the outer side of the deep foundation pit (11) is not less than 50 cm; the pile length of the small-diameter steel pipe pile (1) is anchored into the bottom of the adjacent foundation pit by not less than 1 m;
s2 construction of pile top crown beam
Constructing a pile top crown beam (2) on the top of the small-diameter steel pipe pile (1), and constraining the single-pile small-diameter steel pipe pile (1) into an integral stress structure; l-shaped steel bars are welded on the upper surface and the lower surface of the outer wall of a steel pipe in the small-diameter steel pipe pile (1), the L-shaped steel bars are welded when meeting main bars of a pile top crown beam (2), the pile top crown beam and a constructed crown beam in a deep foundation pit have the same height and the same thickness, and the pile top crown beam and the constructed crown beam are connected into a whole through embedded bars;
s3 construction of foundation reinforcing piles
Adopting a sleeve valve pipe compensation grouting process to construct a foundation reinforcing pile (3), namely drilling a hole at the bottom of a building (12) at an oblique angle of 30-60 degrees towards the right lower part of the building (12) between a small-diameter steel pipe pile (1) and the building (12) to avoid the building foundation (10), then injecting casing materials into the drilled hole, then lowering a sleeve valve pipe, and finally carrying out static pressure grouting construction;
s4 construction of concrete filled steel tubular column
Constructing a steel pipe concrete column (4) at the center of the deep foundation pit (11); the steel pipe concrete column (4) consists of a permanent pile (401) and a temporary steel pipe column (402) anchored into the permanent pile (401); the length of the temporary steel pipe column (402) anchored into the permanent pile (401) is not less than 4 m, a stud is arranged on the outer wall of the anchoring section of the temporary steel pipe column (402), and the periphery of the pile of the temporary steel pipe column (402) is filled with a water-permeable and easily-compact material;
s5, construction of structural slab
Constructing a structural slab (5) at the top of the deep foundation pit (11) to connect the steel pipe concrete column (4) with the enclosure structure (8), the lattice column (9) and the support system in the deep foundation pit (11) to form a whole;
s6 construction of support system
Concrete supports (6) are constructed in the deep foundation pit in a layered mode, and a cross brace (13) and a connecting beam (14) are arranged between the steel pipe concrete column (4) and the lattice column (9), so that the independent supporting structure forms a supporting system.
2. The construction method of the deep foundation pit protection structure adjacent to the high-rise building as claimed in claim 1, wherein in the step S1 of constructing the small-diameter steel pipe pile, the small-diameter steel pipe pile (1) adopts a construction process of subsection, row jump and interval pile jump; the pile spacing and the row spacing of the small-diameter steel pipe piles (1) are 2-3 times of the diameter of the piles, and the small-diameter steel pipe piles are arranged in a quincunx mode.
3. The construction method of the deep foundation pit protection structure adjacent to the high-rise building as claimed in claim 2, wherein in the step S1 of small-diameter steel pipe pile construction, 2-5 m of the anchoring section at the bottom of the small-diameter steel pipe pile (1) adopts quincunx-shaped grouting holes, the grout is cement-water glass double grout, the grout calculates the diffusion radius and the pile spacing, and the grouting is performed in a multiple interval mode.
4. The construction method of the deep foundation pit protection structure adjacent to the high-rise building as claimed in claim 1, wherein in the step S1 of constructing the small-diameter steel pipe pile, the diameter d of the steel pipe used in the small-diameter steel pipe pile (1) is not less than 95 mm and not more than 127 mm, and the wall thickness of the steel pipe used is not less than 8 mm.
5. The construction method of the deep foundation pit protection structure adjacent to the high-rise building as claimed in claim 1, wherein in the step S1 of constructing the small-diameter steel pipe piles, when the depth of the deep foundation pit (11) exceeds 20 m, the number of the rows of the small-diameter steel pipe piles (1) is not less than 3, and when the depth of the deep foundation pit (11) is less than 20 m, the number of the rows of the small-diameter steel pipe piles is not less than 2.
6. The construction method of the deep foundation pit protection structure adjacent to the high-rise building as claimed in claim 1, wherein in the step S2 of constructing the pile top crown beam, the steel pipe top in the small-diameter steel pipe pile (1) is controlled to be exposed from the beam surface of the pile top crown beam (2) by 50-100 mm.
7. The method for constructing a deep foundation pit protection structure adjacent to a high-rise building as claimed in claim 1, wherein the step S3 is a step of constructing the foundation reinforcing piles in which the initial position of the drilled hole is not less than 1 m and not more than 2 m from the building (12).
8. The method for constructing a deep foundation pit protection structure adjacent to a high-rise building as claimed in claim 1, wherein in the step S4 steel core concrete column construction, the diameter of the permanent pile is greater than or equal to that of the enclosure wall or pile in the enclosure structure (8), the anchoring depth of the base of the permanent pile (401) and the concrete mark are the same as those of the enclosure wall or pile in the enclosure structure (8); the diameter of the temporary steel pipe column (402) is more than or equal to 600 mm and less than or equal to 800mm, underwater concrete is poured into the steel pipe, and the mark is the same as that of a surrounding wall or a pile in the enclosure structure (8).
9. The method for constructing a deep foundation pit protection structure adjacent to a high-rise building as claimed in claim 1, wherein in the step S5, when the length of the deep foundation pit (11) adjacent to the building is greater than 54 m, the construction of the construction slab is performed by using a skip method, the skip part of the construction slab is performed by using a forward construction method, the other part is performed by using a reverse construction method, and a hidden beam is additionally arranged in the construction slab which is performed by using the reverse construction method, so as to wrap and connect the steel pipe concrete column (4) and the lattice column (9).
10. The method for constructing a deep foundation pit protection structure adjacent to a high-rise building as claimed in claim 1, wherein the cross braces (13) are I-type I-shaped steel in the construction of the support system of step S6.
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| CN113431097A (en) * | 2021-05-19 | 2021-09-24 | 中国建筑第五工程局有限公司 | Protection structure of shallow foundation building next to deep foundation pit engineering and construction method |
| CN113373901B (en) * | 2021-05-27 | 2023-02-03 | 中建一局集团建设发展有限公司 | Overlapping shield tunnel house foundation reinforcing structure next to house and construction method |
| CN114837455B (en) * | 2022-06-09 | 2023-06-23 | 水利部交通运输部国家能源局南京水利科学研究院 | Method for reconstructing sunken hydraulic building |
| CN115506362B (en) * | 2022-09-02 | 2023-07-25 | 中国建筑第二工程局有限公司 | Mucky soil deep and shallow foundation pit supporting structure and construction method thereof |
| CN116290123B (en) * | 2023-05-17 | 2023-08-04 | 山东省地质矿产勘查开发局八〇一水文地质工程地质大队(山东省地矿工程勘察院) | Device and method for preventing soil layer above bedrock hole from collapsing |
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| UA52031U (en) * | 2010-02-18 | 2010-08-10 | Национальный Авиационный Университет | Method for estimation of effect of deep excavations on adjoining building |
| CN102425172B (en) * | 2011-12-05 | 2013-12-11 | 中冶天工集团有限公司 | Support method for excavating deep foundation pit closely adjacent to high-rise building |
| CN204326080U (en) * | 2014-11-18 | 2015-05-13 | 中大建设有限公司 | A kind of next-door neighbour's existing building pit maintenance soil structure |
| CN105756091B (en) * | 2016-03-16 | 2017-08-01 | 山东理工大学 | A kind of Metro station excavation construction method of control adjacent building composition deformation |
| CN106958250B (en) * | 2017-04-28 | 2023-05-02 | 高创建工股份有限公司 | Supporting method and structure for excavating deep foundation pit close to high-rise building |
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