CN116856462A - Construction method for deep foundation pit shaft structure in narrow space of proximity sensitive building - Google Patents
Construction method for deep foundation pit shaft structure in narrow space of proximity sensitive building Download PDFInfo
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- CN116856462A CN116856462A CN202310535912.8A CN202310535912A CN116856462A CN 116856462 A CN116856462 A CN 116856462A CN 202310535912 A CN202310535912 A CN 202310535912A CN 116856462 A CN116856462 A CN 116856462A
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- 238000010276 construction Methods 0.000 title claims abstract description 89
- 230000002787 reinforcement Effects 0.000 claims abstract description 55
- 239000004567 concrete Substances 0.000 claims abstract description 52
- 238000000034 method Methods 0.000 claims abstract description 47
- 238000005553 drilling Methods 0.000 claims abstract description 30
- 230000008569 process Effects 0.000 claims abstract description 18
- 238000004519 manufacturing process Methods 0.000 claims abstract description 4
- 239000010410 layer Substances 0.000 claims description 56
- 229910000831 Steel Inorganic materials 0.000 claims description 49
- 239000010959 steel Substances 0.000 claims description 49
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 36
- 238000009412 basement excavation Methods 0.000 claims description 35
- 230000003014 reinforcing effect Effects 0.000 claims description 12
- 239000004568 cement Substances 0.000 claims description 11
- 239000007921 spray Substances 0.000 claims description 9
- 239000000463 material Substances 0.000 claims description 7
- 238000004140 cleaning Methods 0.000 claims description 6
- 238000013461 design Methods 0.000 claims description 6
- 238000007689 inspection Methods 0.000 claims description 6
- 238000012423 maintenance Methods 0.000 claims description 6
- 238000012360 testing method Methods 0.000 claims description 6
- 238000003466 welding Methods 0.000 claims description 6
- 239000002023 wood Substances 0.000 claims description 6
- BNIILDVGGAEEIG-UHFFFAOYSA-L disodium hydrogen phosphate Chemical compound [Na+].[Na+].OP([O-])([O-])=O BNIILDVGGAEEIG-UHFFFAOYSA-L 0.000 claims description 5
- 235000019353 potassium silicate Nutrition 0.000 claims description 5
- 238000007789 sealing Methods 0.000 claims description 5
- 239000002002 slurry Substances 0.000 claims description 5
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 claims description 5
- 239000011150 reinforced concrete Substances 0.000 claims description 4
- 239000002689 soil Substances 0.000 claims description 4
- 230000005856 abnormality Effects 0.000 claims description 3
- 238000005266 casting Methods 0.000 claims description 3
- 238000005056 compaction Methods 0.000 claims description 3
- 230000000694 effects Effects 0.000 claims description 3
- 239000003365 glass fiber Substances 0.000 claims description 3
- 230000005484 gravity Effects 0.000 claims description 3
- 239000012535 impurity Substances 0.000 claims description 3
- 238000009434 installation Methods 0.000 claims description 3
- 238000013508 migration Methods 0.000 claims description 3
- 230000005012 migration Effects 0.000 claims description 3
- 239000011241 protective layer Substances 0.000 claims description 3
- 238000005507 spraying Methods 0.000 claims description 3
- 239000003469 silicate cement Substances 0.000 claims description 2
- 238000009825 accumulation Methods 0.000 description 2
- 239000011398 Portland cement Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000002457 bidirectional effect Effects 0.000 description 1
- 238000005034 decoration Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 239000003673 groundwater Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
Classifications
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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
- E02D29/05—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 at least part of the cross-section being constructed in an open excavation or from the ground surface, e.g. assembled in a trench
- E02D29/055—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 at least part of the cross-section being constructed in an open excavation or from the ground surface, e.g. assembled in a trench further excavation of the cross-section proceeding underneath an already installed part of the structure, e.g. the roof of a tunnel
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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
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D31/00—Protective arrangements for foundations or foundation structures; Ground foundation measures for protecting the soil or the subsoil water, e.g. preventing or counteracting oil pollution
- E02D31/02—Protective arrangements for foundations or foundation structures; Ground foundation measures for protecting the soil or the subsoil water, e.g. preventing or counteracting oil pollution against ground humidity or ground water
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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
- E02D5/22—Piles
- E02D5/34—Concrete or concrete-like piles cast in position ; Apparatus for making same
- E02D5/46—Concrete or concrete-like piles cast in position ; Apparatus for making same making in situ by forcing bonding agents into gravel fillings or the soil
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Abstract
The invention relates to a construction method of a deep foundation pit and a vertical shaft structure in a narrow space of a nearby sensitive building, which is characterized by comprising the following steps: step 1, constructing a guide wall of the enclosure structure; step 2, applying a concrete filling pile and a high-pressure jet grouting pile; step 3, constructing a circle of meshed high-pressure jet grouting piles outside the enclosure structure; step 4, manufacturing a reinforcement cage structure for construction; step 5, hanging the reinforcement cage structure; step 6, pouring concrete by adopting a conduit method; step 7, constructing a high-pressure jet grouting pile by adopting a high-pressure jet grouting drilling machine; step 8, excavating and supporting a vertical shaft deep foundation pit; step 9, lining the shaft structure and performing waterproof engineering: and 10, performing construction of an upper backfill layer after construction of the vertical shaft top plate is completed. The construction method has the advantages that: the method has the advantages of rapidness, high efficiency, simplicity and convenience in operation and the like, and saves the construction cost by more than 10% in the construction process of the deep foundation pit of the nearby sensitive building in a certain city in China.
Description
Technical Field
The invention belongs to the technical field of deep foundation pit structure construction, and relates to a construction method for a deep foundation pit shaft structure in a narrow space of a nearby sensitive building.
Background
The deep foundation pit is used as a passage for the construction of the urban tunnel, the construction of the deep foundation pit affects the construction period and the safety of the tunnel, and the safety of the surrounding environment is ensured when the deep foundation pit is supported close to a sensitive building.
In the published chinese patent application document, for example, chinese patent application No. cn201911072879.X discloses a safe construction method for excavation of a deep foundation pit of a shield well and a shaft, wherein the construction method is to arrange an earthwork and a steel support working team to enter after the construction of a concrete support of a fender pile, a dewatering well and a crown Liang Jidi is completed, and perform earthwork excavation and steel support erection; wherein, earth excavation, steel support erection and inter-pile net spray concrete vertically go on in step from top to bottom, each layer of earth excavation depth 1.5m in the vertical direction, follow up with earth excavation and carry out net spray concrete construction, earth excavation is to every steel support below 0.5m, in time erects the steel support and exert prestressing force. According to the safe construction method for the deep foundation pit excavation of the shield well and the vertical shaft, disclosed by the invention, the soil settlement and the foundation pit deformation are strictly controlled in the construction process, so that the anhydrous operation in the construction process of the fine sand layer rich in water powder is ensured, and the construction safety is ensured.
For another example, chinese patent application No. CN202111630496.7 discloses a method for forward and backward construction in a shaft of an ultra-high-rise deep foundation pit, which includes the following steps: (1) Firstly, constructing an underground diaphragm wall, synchronously constructing a core tube and supporting piles and structural engineering piles of round vertical shafts of four giant columns after the core tube and the giant columns of a tower area are positioned and determined, and constructing a skirt house basement structural column; (2) excavating earth of the circular shaft; (3) Constructing a bearing platform and a basement structure of the core tube and the huge column; (4) constructing a first layer beam slab as a positive and a negative boundary; (5) The underground part is reversely operated, the overground part of the tower building area is sequentially operated, and synchronous construction is carried out; and (10) finally, carrying out decoration construction. Compared with the simultaneous forward construction method or the reverse construction method, the construction method of the invention greatly shortens the construction period and saves the construction cost.
The above published patent application is not directed to a method of constructing a deep foundation pit shaft structure in a confined space of a proximity sensitive building.
Disclosure of Invention
The invention aims to ensure the safety of sensitive buildings with the immediate periphery in the deep foundation pit construction process by a series of construction methods. In order to improve the positioning precision of the hole opening of the bored occluding pile and the positioning efficiency, concrete or reinforced concrete enclosure guide walls are applied to the upper part of the pile top. The method comprises the steps of adopting a rotary drilling rig to drill a cast-in-place pile, adopting a high-pressure jet grouting pile to conduct inter-pile reinforcement and water stop between piles, adopting a high-pressure jet grouting pile to conduct stratum reinforcement and water stop on the periphery of a guard pile, forming a foundation pit enclosure structure, constructing a crown Liang Jiguan beam support before shaft deep foundation pit excavation, constructing a drainage well in the pit, guaranteeing that the groundwater level is always 0.5m below an excavation face in each layered excavation process, timely conducting anchor jet support on the periphery of a well wall in the excavation process, excavating the shaft to the bottom, conducting back cover concrete pouring, observing peripheral settlement and displacement, paving waterproof plates on structural lining base faces to block external leakage water sources, conducting beam plate construction inside the shaft in a layered mode to form an integral frame, and finally backfilling the shaft to finish site recovery and other works.
The invention aims to overcome the defects in the prior art and provides a construction method of a deep foundation pit and a vertical shaft structure in a narrow space adjacent to a sensitive building, which comprises the following steps:
step 1, constructing a building enclosure guide wall:
step 1.1, leveling a site, measuring and placing pile positions, removing surface impurities, removing surface depth of 0.3m, and filling up grooves for pipeline migration on the ground;
step 1.2, calculating coordinates of a central line of the row pile according to coordinates provided by a design drawing, carrying out field lofting by adopting a total station according to a ground lead control point, and applying a maintenance pile as a control central line of guide wall construction;
step 1.3, excavating a guide wall groove according to a pile position lofting line, wherein the excavation depth is 1.5m below the ground, and after the excavation is finished, introducing a central line under the groove so as to control the construction of a bottom die and a template; the width of the guide wall is 4m, the thickness of the guide wall is 0.3m, the diameter of the positioning hole is 1.05m, the elevation of the top surface is 5cm higher than the ground, and the deviation between the center of the reserved hole of the guide wall and the center of the pile position is not more than 20mm;
and 2, applying a concrete filling pile and a high-pressure jet grouting pile:
step 2.1, after the guide wall construction is completed, repositioning the center position of the lofting and pile arranging, putting a positioning point on the top surface of the guide wall, taking the positioning point as a positioning control point of a drilling machine, moving the drilling machine to be in place, and correspondingly positioning the center of a drill bit of the drilling machine at the center of the positioning point of the guide wall;
2.2, drilling the bored pile by adopting a rotary drilling rig, and detecting verticality in the drilling process until reaching the hole bottom elevation designed for the bored pile hole, wherein the verticality of the bored pile hole is not less than 0.05mm;
step 2.3, after the bored pile hole is bored and before the concrete is poured, the bored pile hole is subjected to periodical pore-forming quality inspection, and after the bored pile hole reaches the designed elevation, the bored pile hole is cleaned;
step 2.4, constructing a filling pile, adopting a high-pressure rotary spray grouting pile, forming a pile gap between the filling piles, and injecting water stop slurry reinforcement water stop consisting of cement paste and materials with reinforcement water stop effect into the pile gap, wherein 37 vertical shaft filling piles are arranged, wherein 5 phi 1200 piles and 32 phi 1000 piles are arranged, the pile gap of the filling pile is reinforced and stopped by adopting a high-pressure rotary spray pile, and the outer side of a foundation pit is reinforced and stopped by adopting a meshed high-pressure rotary spray pile mode to form a maintenance structure;
and 3, constructing a circle of meshed high-pressure jet grouting piles outside the enclosure structure, reinforcing and sealing water for the stratum, wherein the reinforcing and sealing water adopts Portland cement, water glass and disodium hydrogen phosphate according to the mass part ratio 1:0.5:0.2, and the next working procedure can be carried out after the reinforcing water stop construction is carried out for 30 min;
step 4: manufacturing and constructing a reinforcement cage structure:
the steel reinforcement cage structure is provided with transverse and longitudinal staggered truss ribs, L-shaped shear steel bars are welded at transverse and longitudinal lap joints of the truss ribs, the lap joint length of steel bar ends and glass fiber bar ends is 30cm, transverse I-shaped steel is arranged at two longitudinal sides of the truss ribs, each side of each L-shaped shear steel bar is 30cm, each L-shaped shear steel bar is welded with one side of the truss rib, and the welding length is 10 times the diameter of each L-shaped shear steel bar;
and 5, hanging the reinforcement cage structure:
step 5.1, arranging a hoisting point: arranging 4 hoisting points in the length direction of the steel reinforcement cage, arranging 2 points at the hoisting points of the main crane, arranging 2 points at the hoisting points of the auxiliary crane, determining the positions according to the size of the steel reinforcement cage, and welding 4 hoisting rings on the longitudinal truss ribs of the steel reinforcement cage;
step 5.2, hoisting the reinforcement cage by adopting a main crane and an auxiliary crane which are QUY80 type 80t crawler cranes;
step 5.3, hoisting the reinforcement cage: transferring the crane to a hoisting position, and respectively installing shackles of the hoisting points; checking the installation and the stress gravity center conditions of the two crane steel wire ropes, and continuing hoisting after the crane is intact and has no abnormality;
step 5.4, the main crane and the auxiliary crane are matched to hoist the reinforcement cage to a preset position, so that the reinforcement cage is perpendicular to the ground;
step 5.5, disassembling a lifting point shackle of the auxiliary crane on the reinforcement cage, and withdrawing the operation range of the main crane; the main crane moves the reinforcement cage to a lowering position, and the reinforcement cage is integrally hoisted in place;
and 6, pouring concrete by adopting a conduit method:
pouring concrete by adopting a conduit method, taking three groups of test pieces from each batch of concrete material, monitoring slump of the test pieces, pouring concrete and drawing a pipe at the same time, and always keeping the bottom of the sleeve lower than the concrete surface by not less than 2.5m;
and 7, constructing a high-pressure jet grouting pile by adopting a high-pressure jet grouting drilling machine:
adopting a high-pressure rotary jet drilling machine to jet grouting piles, performing foundation pit water stop by adopting a phi 800@1200 mm+a phi 800@600 rotary jet grouting pile curtain outside the piles among the rotary jet grouting piles, and performing rotary jet grouting waterproof curtain construction by adopting the high-pressure rotary jet drilling machine after the construction of the guard piles is completed, wherein the cement slurry water-cement ratio is 1:1, and the doping amount of the rotary jet grouting piles is 375KG per meter;
step 8, excavating and supporting a vertical shaft deep foundation pit:
8.1, carrying out crown beam construction and crown beam support before shaft excavation, arranging four concrete diagonal braces and a diagonal brace in the first step, casting the crown beam and the crown beam together to form a whole, wherein a support system consists of the crown beam, the concrete support, the waist beam and the concrete diagonal brace, the waist beam structure form is divided into two sections of 900 x 1000mm and 1000 x 1000mm, the diagonal brace structure form is a section of 800 x 1000mm, and carrying out anchor spraying support on the periphery of a shaft wall in the process of shaft deep foundation pit excavation;
step 8.2, shaft excavation, namely firstly cleaning surface soil, then excavating a first layer of earthwork, constructing a first waist beam, supporting and excavating a second layer of earthwork, constructing a second waist beam, supporting, excavating a third layer of earthwork, constructing a third waist beam, supporting, excavating a fourth layer of earthwork, constructing a fourth waist beam, supporting, excavating a fifth layer of earthwork, then carrying out bottom cleaning, groove inspection, cushion layer construction to the bottom, and carrying out bottom sealing concrete pouring;
step 8.3, paving a waterproof board protective layer on the base surface of the main shaft structure so as to block an external seepage water source;
step 8.4, binding the steel bars of the bottom plate of the vertical shaft;
8.5, pouring bottom plate concrete, and arranging a dredging well in the middle of a deep foundation pit of the vertical shaft so as to reduce the water level in the process of excavation of the foundation pit and ensure that the excavation surface is free from water accumulation;
step 9, lining the shaft structure and performing waterproof engineering:
9.1, the shaft lining is made of waterproof reinforced concrete with the thickness of C35 and P8, the thickness of the bottom plate lining is 1200mm, the thickness of the well wall lining is 900mm, the construction is performed by adopting a bottom-up method, after excavation and support are completed, a shaft bottom is cleaned, a shaft bottom waterproof layer is paved, bottom plate steel bars are bound, and shaft bottom concrete is poured;
step 9.2, dismantling waist beams and supports from bottom to top in sequence, erecting a steel pipe scaffold and a working platform, paving a well wall waterproof layer, binding a well wall steel bar supporting template, adopting a wood template and a steel pipe support as the template, putting a string of cylinders into a well to a lining section, vibrating and reinforcing by using an inserted vibrator, and sequentially and circularly carrying out lining construction of the next procedure;
9.3, the vertical shaft is a working shaft, the clearance size in the vertical shaft is 12.9 x 4.5m, the internal structure of the vertical shaft is 3 layers, each layer of vertical shaft structure well wall and frame beams are applied, the upper foundation pit support can be removed after each layer of well wall reaches 90% of the design strength, the total height of the vertical shaft is 16.2m, the beam plates are constructed in a layered manner from bottom to top, a full scaffold is erected, and a wood template is used as a floor bottom die;
step 10, performing upper backfill layer construction after shaft roof construction is completed:
the vertical shaft backfilling adopts a layer backfilling process, the backfilling thickness of each layer is not more than 300mm, the compaction pass number of each layer is 4, the tamping machine is used for tamping, the backfilling layer thickness is 2.0m, and C25 concrete with the thickness of 500mm is poured at the top of the backfilling layer.
The construction method for the deep foundation pit shaft structure in the narrow space of the proximity sensitive building has the beneficial effects that:
the construction method of the deep foundation pit shaft structure in the narrow space of the near-sensitive building has the advantages of being rapid, efficient, simple and convenient to operate and the like, and construction cost is saved by more than 10% in the construction process of the deep foundation pit of the near-sensitive building in a certain city in China.
2, the construction method of the deep foundation pit shaft structure in the narrow space of the near-sensitive building improves the construction efficiency by more than 20% in the construction engineering of certain city in China.
The construction method of the deep foundation pit shaft structure in the narrow space close to the sensitive building can ensure the safety of the construction surrounding environment.
Drawings
Fig. 1 is a schematic flow chart of a construction method of a deep foundation pit shaft structure in a narrow space of a proximity sensitive building.
Detailed Description
The method for constructing the deep foundation pit of the proximity sensitive building is further described in detail below with reference to the attached drawings and the detailed description.
As shown in fig. 1, the construction method of the deep foundation pit shaft structure in the narrow space of the proximity sensitive building comprises the following steps:
step 1, constructing a building enclosure guide wall:
step 1.1, leveling a site, measuring and placing pile positions, removing surface impurities, removing surface depth of 0.3m, and filling up grooves for pipeline migration on the ground;
step 1.2, calculating coordinates of a central line of the row pile according to the coordinates provided by the design, carrying out field lofting by adopting a total station according to a ground lead control point, and applying a maintenance pile as a control central line of the guide wall construction;
step 1.3, excavating a guide wall groove according to a pile position lofting line, wherein the excavation depth is 1.5m below the ground, and after the excavation is finished, introducing a central line under the groove so as to control the construction of a bottom die and a template; the width of the guide wall is 2m at each side, the thickness of the guide wall is 30cm, the guide wall is poured by adopting concrete with the strength grade of C30, steel bars are made of HPB235 grade steel, the guide wall is reinforced with double layers of bidirectional phi 12@150, the guide wall is 4m in width and 0.3m in thickness, the diameter of a positioning hole is 1.05m, the elevation of the top surface is 5cm higher than the ground, and the deviation between the center of a reserved hole of the guide wall and the center of a pile position is not more than 20mm;
and 2, applying a concrete filling pile and a high-pressure jet grouting pile:
step 2.1, after the guide wall construction is completed, repositioning the center position of the lofting and pile arranging, putting a positioning point on the top surface of the guide wall, taking the positioning point as a positioning control point of a drilling machine, moving the drilling machine to be in place, and correspondingly positioning the center of a drill bit of the drilling machine at the center of the positioning point of the guide wall;
2.2, drilling the bored pile by adopting a rotary drilling rig, and detecting verticality in the drilling process until reaching the hole bottom elevation designed for the bored pile hole, wherein the verticality of the bored pile hole is not less than 0.05mm;
step 2.3, after the bored pile hole is bored and before concrete is poured, the bored pile hole is subjected to periodic pore-forming quality inspection, and after the bored pile reaches the designed elevation, the bore diameter, the bore depth, the hole position and the verticality are detected to be qualified, namely the bored pile hole is cleaned;
step 2.4, constructing a filling pile, adopting a high-pressure rotary spray grouting pile, forming a pile gap between the filling piles, and injecting water stop slurry reinforcement water stop consisting of cement paste and materials with reinforcement water stop effect into the pile gap, wherein 37 vertical shaft filling piles are arranged, wherein 5 phi 1200 piles and 32 phi 1000 piles are arranged, the pile gap of the filling pile is reinforced and stopped by adopting a high-pressure rotary spray pile, and the outer side of a foundation pit is reinforced and stopped by adopting a meshed high-pressure rotary spray pile mode to form a maintenance structure;
and 3, constructing the meshed high-pressure jet grouting pile outside the enclosure structure:
after the construction of a circle of meshed high-pressure jet grouting piles is completed, reinforcing and water stopping are carried out on the stratum, silicate cement, water glass and disodium hydrogen phosphate are adopted as reinforcing and water stopping materials, and the cement, water glass and disodium hydrogen phosphate are mixed according to the following weight ratio of 1:0.5:0.2, and the next working procedure can be carried out after the reinforcing water stop construction is carried out for 30 min;
step 4: manufacturing a reinforcement cage structure:
the steel reinforcement cage is provided with transverse and longitudinal staggered truss ribs, L-shaped shear steel bars are welded at transverse and longitudinal lap joints of the truss ribs, the lap joint length of steel bar ends and glass fiber bar ends is 30cm, transverse I-shaped steel is arranged at two longitudinal sides of the truss ribs, each side of each L-shaped shear steel bar is 30cm, each L-shaped shear steel bar is welded with one side of the truss rib, and the welding length is ten times the diameter of each L-shaped shear steel bar;
and 5, hanging the reinforcement cage structure:
step 5.1, arranging a hoisting point: arranging 4 hoisting points in the length direction of the steel reinforcement cage, arranging 2 points at the hoisting points of the main crane, arranging 2 points at the hoisting points of the auxiliary crane, determining the positions according to the size of the steel reinforcement cage, and welding 4 hoisting rings on the longitudinal truss ribs of the steel reinforcement cage;
step 5.2, hoisting the reinforcement cage by adopting a main crane and an auxiliary crane which are QUY80 type 80t crawler cranes;
step 5.3, hoisting the reinforcement cage: transferring the crane to a hoisting position, and respectively installing shackles of the hoisting points; checking the installation and the stress gravity center conditions of the two crane steel wire ropes, and continuing hoisting after the crane is intact and has no abnormality;
step 5.4, the main crane and the auxiliary crane are matched to hoist the reinforcement cage to a preset position, so that the reinforcement cage is perpendicular to the ground;
step 5.5, disassembling a lifting point shackle of the auxiliary crane on the reinforcement cage, and withdrawing the operation range of the main crane; the main crane moves the reinforcement cage to a lowering position, and the reinforcement cage is integrally hoisted in place;
and 6, pouring concrete:
the concrete pouring adopts a conduit method, three groups of test pieces are taken for each car of concrete, the slump of the test pieces is monitored, the concrete is poured and the pipe is pulled out, and the bottom of the sleeve pipe is always kept to be not less than 2.5m below the concrete surface;
and 7, constructing a high-pressure jet grouting pile by adopting a high-pressure jet grouting drilling machine:
adopting a high-pressure rotary jet drilling machine to jet grouting piles, performing foundation pit water stop by adopting a phi 800@1200 (1400) mm between the rotary jet piles and a phi 800@600 rotary jet grouting pile curtain outside the piles, and performing rotary jet grouting water stop curtain construction by adopting the high-pressure rotary jet drilling machine after the construction of the guard piles is completed, wherein the cement slurry water-cement ratio is 1:1, and the mixing amount of the rotary jet piles per meter is 375KG;
step 8, excavating and supporting a vertical shaft deep foundation pit:
8.1, carrying out crown beam construction and crown beam support before shaft excavation, arranging four concrete diagonal braces and a diagonal brace in the first step, casting the crown beam and the crown beam together to form a whole, wherein a support system consists of the crown beam, the concrete support, the waist beam and the concrete diagonal brace, the waist beam structure form is divided into two sections of 900 x 1000mm and 1000 x 1000mm, the diagonal brace structure form is a section of 800 x 1000mm, and carrying out anchor spraying support on the periphery of a shaft wall in the process of shaft deep foundation pit excavation;
step 8.2, shaft excavation, namely firstly cleaning surface soil, then excavating a first layer of earthwork, constructing a first waist beam, supporting and excavating a second layer of earthwork, constructing a second waist beam, supporting, excavating a third layer of earthwork, constructing a third waist beam, supporting, excavating a fourth layer of earthwork, constructing a fourth waist beam, supporting, excavating a fifth layer of earthwork, then carrying out bottom cleaning, groove inspection, cushion layer construction to the bottom, and carrying out bottom sealing concrete pouring;
step 8.3, paving a waterproof board protective layer on the base surface of the main shaft structure so as to block an external seepage water source;
step 8.4, binding the steel bars of the bottom plate of the vertical shaft;
8.5, pouring bottom plate concrete, and arranging a dredging well in the middle of a deep foundation pit of the vertical shaft so as to reduce the water level in the process of excavation of the foundation pit and ensure that the excavation surface is free from water accumulation;
step 9, lining the shaft structure and performing waterproof engineering:
9.1, the shaft lining is made of waterproof reinforced concrete with the thickness of C35 and P8, the thickness of the bottom plate lining is 1200mm, the thickness of the well wall lining is 900mm, the construction is performed by adopting a bottom-up method, after excavation and support are completed, a shaft bottom is cleaned, a shaft bottom waterproof layer is paved, bottom plate steel bars are bound, and shaft bottom concrete is poured;
step 9.2, dismantling waist beams and supports from bottom to top in sequence, erecting a steel pipe scaffold and a working platform, paving a well wall waterproof layer, binding a well wall steel bar supporting template, adopting a wood template and a steel pipe support as the template, putting a string of cylinders into a well to a lining section, vibrating and reinforcing by using an inserted vibrator, and sequentially and circularly carrying out lining construction of the next procedure;
9.3, the vertical shaft is a working shaft, the clearance size in the vertical shaft is 12.9 x 4.5m, the internal structure of the vertical shaft is 3 layers, each layer of vertical shaft structure well wall and frame beams are applied, the upper foundation pit support can be removed after each layer of well wall reaches 90% of the design strength, the total height of the vertical shaft is 16.2m, the beam plates are constructed in a layered manner from bottom to top, a full scaffold is erected, and a wood template is used as a floor bottom die;
step 10, after construction of a vertical shaft top plate is completed, construction of an upper backfill layer is carried out:
the vertical shaft backfill adopts layer backfill, the backfill thickness of each layer is not more than 300mm, the compaction times of each layer are 4 times, the tamping machine is used for tamping, the backfill layer thickness is 2.0m, and C25 concrete with the thickness of 500mm is poured at the top of the backfill layer.
The present invention is not limited to the above-described embodiments, and any modifications, improvements, substitutions, and the like, which can be conceived by those skilled in the art, fall within the scope of the present invention without departing from the spirit of the invention.
Claims (10)
1. The construction method of the deep foundation pit and shaft structure in the narrow space of the proximity sensitive building is characterized by comprising the following steps:
step 1, constructing a guide wall of the enclosure structure;
step 2, applying a concrete filling pile and a high-pressure jet grouting pile;
step 3, constructing a circle of meshed high-pressure jet grouting piles outside the enclosure structure;
step 4, manufacturing a reinforcement cage structure for construction;
step 5, hanging the reinforcement cage structure;
step 6, pouring concrete by adopting a conduit method;
step 7, constructing a high-pressure jet grouting pile by adopting a high-pressure jet grouting drilling machine;
step 8, excavating and supporting a vertical shaft deep foundation pit;
step 9, lining the shaft structure and performing waterproof engineering:
and 10, performing construction of an upper backfill layer after construction of the vertical shaft top plate is completed.
2. The method for constructing deep foundation pit and shaft structures in a small space of a proximity sensitive building according to claim 1, wherein the constructing the enclosure guide wall in step 1 comprises:
step 1.1, leveling a site, measuring and placing pile positions, removing surface impurities, removing surface depth of 0.3m, and filling up grooves for pipeline migration on the ground;
step 1.2, calculating coordinates of a central line of the row pile according to coordinates provided by a design drawing, carrying out field lofting by adopting a total station according to a ground lead control point, and applying a maintenance pile as a control central line of guide wall construction;
step 1.3, excavating a guide wall groove according to a pile position lofting line, wherein the excavation depth is 1.5m below the ground, and after the excavation is finished, introducing a central line under the groove so as to control the construction of a bottom die and a template; the guide wall has the width of 4m, the thickness of 0.3m, the diameter of the positioning hole of 1.05m, and the elevation of the top surface of 5cm higher than the ground, and the deviation between the center of the reserved hole of the guide wall and the center of the pile position is not more than 20mm.
3. The method for constructing deep foundation pit and shaft structures in small spaces of proximity-sensitive buildings according to claim 1, wherein the concrete cast-in-place piles and high-pressure jet grouting piles applied in step 2 comprise:
step 2.1, after the guide wall construction is completed, repositioning the center position of the lofting and pile arranging, putting a positioning point on the top surface of the guide wall, taking the positioning point as a positioning control point of a drilling machine, moving the drilling machine to be in place, and correspondingly positioning the center of a drill bit of the drilling machine at the center of the positioning point of the guide wall;
2.2, drilling the bored pile by adopting a rotary drilling rig, and detecting verticality in the drilling process until reaching the hole bottom elevation designed for the bored pile hole, wherein the verticality of the bored pile hole is not less than 0.05mm;
step 2.3, after the bored pile hole is bored and before the concrete is poured, the bored pile hole is subjected to periodical pore-forming quality inspection, and after the bored pile hole reaches the designed elevation, the bored pile hole is cleaned;
step 2.4, constructing the cast-in-place piles, adopting high-pressure rotary spray grouting piles, forming water stop grouting material reinforced water stop consisting of cement paste and materials with reinforced water stop effect in gaps among the cast-in-place piles, arranging 37 vertical shaft cast-in-place piles,5 piles, 10>And the 32 piles are reinforced and waterstopped by adopting high-pressure jet grouting piles among the piles of the cast-in-place piles, and the outer side of the foundation pit is reinforced and waterstopped by adopting a meshed high-pressure jet grouting pile mode to form a maintenance structure.
4. The method for constructing deep foundation pit and shaft structure in narrow space of proximity sensitive building according to claim 1, wherein in step 3, a circle of meshed high-pressure jet grouting piles are constructed outside the enclosure structure:
after the construction of a circle of meshed high-pressure jet grouting piles is completed, reinforcing and water stopping are carried out on the stratum, silicate cement, water glass and disodium hydrogen phosphate are adopted for reinforcing and water stopping, and the cement, water glass and disodium hydrogen phosphate are mixed according to the following weight ratio of 1:0.5:0.2, and the next working procedure can be carried out after the reinforcing water stop construction is carried out for 30 min.
5. The method for constructing deep foundation pit and shaft structures in a small space of a proximity sensitive building according to claim 1, wherein the reinforcement cage structure for construction in step 4 comprises:
the transverse and longitudinal staggered truss ribs of the reinforcement cage structure are arranged, L-shaped shear reinforcements are welded at transverse and longitudinal lap joints of the truss ribs, the lap joint length of the reinforcement ends and the glass fiber reinforcement ends is 30cm, transverse I-shaped steel is arranged on two longitudinal sides of the truss ribs, each side of each L-shaped shear reinforcement is 30cm, each L-shaped shear reinforcement is welded with one side of the truss rib, and the welding length is 10 times the diameter of each L-shaped shear reinforcement.
6. The method for constructing deep foundation pit and shaft structures in a small space of a proximity-sensitive building according to claim 1, wherein the hanging reinforcement cage structure in step 5 comprises:
step 5.1, arranging a hoisting point: arranging 4 hoisting points in the length direction of the steel reinforcement cage, arranging 2 points at the hoisting points of the main crane, arranging 2 points at the hoisting points of the auxiliary crane, determining the positions according to the size of the steel reinforcement cage, and welding 4 hoisting rings on the longitudinal truss ribs of the steel reinforcement cage;
step 5.2, hoisting the reinforcement cage by adopting a main crane and an auxiliary crane which are QUY80 type 80t crawler cranes;
step 5.3, hoisting the reinforcement cage: transferring the crane to a hoisting position, and respectively installing shackles of the hoisting points; checking the installation and the stress gravity center conditions of the two crane steel wire ropes, and continuing hoisting after the crane is intact and has no abnormality;
step 5.4, the main crane and the auxiliary crane are matched to hoist the reinforcement cage to a preset position, so that the reinforcement cage is perpendicular to the ground;
step 5.5, disassembling a lifting point shackle of the auxiliary crane on the reinforcement cage, and withdrawing the operation range of the main crane; and the main crane moves the reinforcement cage to a lowering position, and the reinforcement cage is integrally hoisted in place.
7. The method for constructing deep foundation pit and shaft structures in small spaces of proximity sensitive buildings according to claim 1, wherein in step 6, concrete by a pipe-guiding pouring method is adopted: three groups of test pieces are taken for each batch of concrete materials, the slump of the test pieces is monitored, concrete is poured and the pipe is drawn, and the bottom of the sleeve pipe is always kept to be not smaller than 2.5m below the concrete surface.
8. The method for constructing deep foundation pit and shaft structures in narrow spaces of proximity sensitive buildings according to claim 1, wherein in step 7, high-pressure jet grouting piles are constructed by adopting a high-pressure jet grouting drilling machine:
adopting a high-pressure rotary jet drilling machine to jet grouting piles, performing foundation pit water stop by adopting a phi 800@1200 mm+a phi 800@600 rotary jet grouting pile curtain outside the piles among the rotary jet grouting piles, and performing rotary jet grouting water stop curtain construction by adopting the high-pressure rotary jet drilling machine after the construction of the guard piles is completed, wherein the cement slurry water-cement ratio is 1:1, and the doping amount of the rotary jet grouting piles per meter is 375KG.
9. The method for constructing a deep foundation pit and a shaft structure in a small space of a proximity sensitive building according to claim 1, wherein the shaft deep foundation pit excavation and support in step 8 comprises:
8.1, carrying out crown beam construction and crown beam support before shaft excavation, arranging four concrete diagonal braces and a diagonal brace in the first step, casting the crown beam and the crown beam together to form a whole, wherein a support system consists of the crown beam, the concrete support, the waist beam and the concrete diagonal brace, the waist beam structure form is divided into two sections of 900 x 1000mm and 1000 x 1000mm, the diagonal brace structure form is a section of 800 x 1000mm, and carrying out anchor spraying support on the periphery of a shaft wall in the process of shaft deep foundation pit excavation;
step 8.2, shaft excavation, namely firstly cleaning surface soil, then excavating a first layer of earthwork, constructing a first waist beam, supporting and excavating a second layer of earthwork, constructing a second waist beam, supporting, excavating a third layer of earthwork, constructing a third waist beam, supporting, excavating a fourth layer of earthwork, constructing a fourth waist beam, supporting, excavating a fifth layer of earthwork, then carrying out bottom cleaning, groove inspection, cushion layer construction to the bottom, and carrying out bottom sealing concrete pouring;
step 8.3, paving a waterproof board protective layer on the base surface of the main shaft structure so as to block an external seepage water source;
step 8.4, binding the steel bars of the bottom plate of the vertical shaft;
and 8.5, pouring bottom plate concrete, and arranging a dredging well in the middle of a deep foundation pit of the vertical shaft so as to reduce the water level in the process of excavation of the foundation pit, wherein the bottom plate concrete is convenient for dredging accumulated water at the bottom of the vertical shaft.
10. The method for constructing deep foundation pit and shaft structure in narrow space of proximity sensitive building according to claim 1, wherein the shaft structure lining and construction of waterproof engineering in step 9 comprises:
9.1, the shaft lining is made of waterproof reinforced concrete with the thickness of C35 and P8, the thickness of the bottom plate lining is 1200mm, the thickness of the well wall lining is 900mm, the construction is performed by adopting a bottom-up method, after excavation and support are completed, a shaft bottom is cleaned, a shaft bottom waterproof layer is paved, bottom plate steel bars are bound, and shaft bottom concrete is poured;
step 9.2, dismantling waist beams and supports from bottom to top in sequence, erecting a steel pipe scaffold and a working platform, paving a well wall waterproof layer, binding a well wall steel bar supporting template, adopting a wood template and a steel pipe support as the template, putting a string of cylinders into a well to a lining section, vibrating and reinforcing by using an inserted vibrator, and sequentially and circularly carrying out lining construction of the next procedure;
9.3, the vertical shaft is a working shaft, the clearance size in the vertical shaft is 12.9 x 4.5m, the internal structure of the vertical shaft is 3 layers, each layer of vertical shaft structure well wall and frame beams are applied, the upper foundation pit support can be removed after each layer of well wall reaches 90% of the design strength, the total height of the vertical shaft is 16.2m, the beam plates are constructed in a layered manner from bottom to top, a full scaffold is erected, and a wood template is used as a floor bottom die; and (3) carrying out construction of an upper backfill layer after construction of the vertical shaft top plate is completed: the vertical shaft backfilling adopts a layer backfilling process, the backfilling thickness of each layer is not more than 300mm, the compaction pass number of each layer is 4, the tamping machine is used for tamping, the backfilling layer thickness is 2.0m, and C25 concrete with the thickness of 500mm is poured at the top of the backfilling layer.
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