CN116556357A - Construction method of deep foundation pit under high side slope condition - Google Patents
Construction method of deep foundation pit under high side slope condition Download PDFInfo
- Publication number
- CN116556357A CN116556357A CN202310671272.3A CN202310671272A CN116556357A CN 116556357 A CN116556357 A CN 116556357A CN 202310671272 A CN202310671272 A CN 202310671272A CN 116556357 A CN116556357 A CN 116556357A
- Authority
- CN
- China
- Prior art keywords
- construction
- concrete
- foundation pit
- construction method
- soil
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000010276 construction Methods 0.000 title claims abstract description 128
- 239000002689 soil Substances 0.000 claims abstract description 69
- 239000004567 concrete Substances 0.000 claims abstract description 65
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 54
- 239000010959 steel Substances 0.000 claims abstract description 54
- 238000009412 basement excavation Methods 0.000 claims abstract description 41
- 229910001294 Reinforcing steel Inorganic materials 0.000 claims abstract description 19
- 239000011378 shotcrete Substances 0.000 claims abstract description 6
- 238000001514 detection method Methods 0.000 claims abstract description 4
- 239000010410 layer Substances 0.000 claims description 22
- 239000002344 surface layer Substances 0.000 claims description 18
- 238000005553 drilling Methods 0.000 claims description 13
- 239000011150 reinforced concrete Substances 0.000 claims description 12
- 239000002002 slurry Substances 0.000 claims description 12
- 238000005507 spraying Methods 0.000 claims description 11
- 238000000034 method Methods 0.000 claims description 8
- 230000007613 environmental effect Effects 0.000 claims description 4
- 230000002787 reinforcement Effects 0.000 claims description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 4
- 238000003466 welding Methods 0.000 claims description 4
- 239000002023 wood Substances 0.000 claims description 4
- 230000002457 bidirectional effect Effects 0.000 claims description 3
- 238000005253 cladding Methods 0.000 claims description 3
- 239000011120 plywood Substances 0.000 claims description 3
- 238000009415 formwork Methods 0.000 claims 1
- 238000007689 inspection Methods 0.000 claims 1
- 238000013461 design Methods 0.000 abstract description 9
- 230000000694 effects Effects 0.000 abstract description 2
- 239000007921 spray Substances 0.000 abstract 1
- 239000004568 cement Substances 0.000 description 8
- 230000003014 reinforcing effect Effects 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 239000002131 composite material Substances 0.000 description 3
- 239000004575 stone Substances 0.000 description 3
- 241001079814 Symphyotrichum pilosum Species 0.000 description 2
- 235000004224 Typha angustifolia Nutrition 0.000 description 2
- 239000011449 brick Substances 0.000 description 2
- 238000005266 casting Methods 0.000 description 2
- 238000007599 discharging Methods 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 238000012423 maintenance Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 239000003973 paint Substances 0.000 description 2
- 238000012876 topography Methods 0.000 description 2
- 239000011398 Portland cement Substances 0.000 description 1
- 239000010426 asphalt Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000005056 compaction Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000007667 floating Methods 0.000 description 1
- 239000003365 glass fiber Substances 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 239000011241 protective layer Substances 0.000 description 1
- 239000011435 rock Substances 0.000 description 1
- 238000012216 screening Methods 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 238000007569 slipcasting Methods 0.000 description 1
- 239000002436 steel type Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000001502 supplementing effect Effects 0.000 description 1
Classifications
-
- 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
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D15/00—Handling building or like materials for hydraulic engineering or foundations
- E02D15/02—Handling of bulk concrete specially for foundation or hydraulic engineering purposes
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D15/00—Handling building or like materials for hydraulic engineering or foundations
- E02D15/02—Handling of bulk concrete specially for foundation or hydraulic engineering purposes
- E02D15/04—Placing concrete in mould-pipes, pile tubes, bore-holes or narrow shafts
-
- 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
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
- E02D5/74—Means for anchoring structural elements or bulkheads
- E02D5/76—Anchorings for bulkheads or sections thereof in as much as specially adapted therefor
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D2250/00—Production methods
- E02D2250/0007—Production methods using a mold
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D2250/00—Production methods
- E02D2250/0023—Cast, i.e. in situ or in a mold or other formwork
-
- 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
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D2600/00—Miscellaneous
- E02D2600/30—Miscellaneous comprising anchoring details
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Structural Engineering (AREA)
- Mining & Mineral Resources (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Paleontology (AREA)
- Civil Engineering (AREA)
- Pit Excavations, Shoring, Fill Or Stabilisation Of Slopes (AREA)
Abstract
A construction method of deep foundation pit under high side slope condition, (1) construction of construction channel; (2) constructing a steel pipe pile at a high side slope; (3) The earthwork excavation is carried out in the foundation pit from top to bottom, the first section of earthwork is directly excavated, the excavation of the other sections of earthwork is completed by the support construction of the previous section, and the detection is qualified; (4) After the earth of the section is excavated, the surface of the soil body is sprayed with a concrete protection surface; (5) soil nailing construction is carried out in the soil layer; (6) Constructing a hanging net on the surface of the concrete facing to spray concrete; (7) binding reinforcing steel bars on the inner side of the net-hanging sprayed concrete; (8) setting up a template; (9) pouring concrete to finish the support construction of the section; (10) Repeating the steps (3) - (9) until the foundation pit bottom is constructed; and (11) binding the bottom plate steel bars and pouring bottom plate concrete. The support structure has reasonable design, simple construction steps, large support depth and good use effect, and belongs to the technical field of foundation pit construction.
Description
Technical Field
The invention relates to a foundation pit construction technology, in particular to a construction method of a deep foundation pit under a high side slope condition, which is suitable for the construction of the deep foundation pit under the high side slope condition of complex terrains.
Background
Along with the rapid development and construction of urban traffic, the urban traffic gradually develops towards a three-dimensional space direction, and the construction of various underground projects is more and more, so that the travelling elevator is one of the solutions.
The high slope means that the soil slope height is more than 20m and less than 100m or the rock slope height is more than 30m and less than 100m. At present, the main construction sequence of foundation pit excavation is forward construction method and reverse construction method, and the deep foundation pit is usually supported firstly and excavated later.
The construction of deep foundation pit support is carried out on a high side slope, large-scale equipment such as a steel sheet pile machine and the like of conventional foundation pit support on construction equipment cannot enter, the use of the underground continuous wall support is more difficult to realize, the construction under the high side slope topography easily causes side slope collapse, personnel, equipment slip and other risks, and the prior art is difficult to consider in terms of construction convenience, construction speed and safety for deep foundation pit excavation under the high side slope condition.
Disclosure of Invention
Aiming at the technical problems existing in the prior art, the invention aims at: the construction method of the deep foundation pit under the high side slope condition is provided, and the construction convenience, the construction speed and the safety are considered.
In order to achieve the above purpose, the invention adopts the following technical scheme:
a construction method of a deep foundation pit under a high side slope condition comprises the following steps: (1) constructing a construction channel on a hillside; (2) At the high side slope, constructing a steel pipe pile corresponding to soil bodies outside three sides of the foundation pit; (3) The earthwork excavation is carried out in the foundation pit from top to bottom, the earthwork of the first section is directly excavated, the excavation of the earthwork of the other sections except the first section is completed by the support construction of the last section, and the detection is qualified; (4) After the earthwork of the section is excavated, concrete facing is sprayed on the surfaces of the soil bodies of the three faces corresponding to the foundation pit; (5) performing soil nailing construction in the soil layer facing the concrete guard; (6) After the soil nail construction is completed, constructing a net hanging and concrete spraying on the surface of the concrete facing; (7) binding reinforcing steel bars on the inner side of the net-hanging sprayed concrete; (8) setting up a template; (9) Pouring concrete, constructing a reinforced concrete support plate and a reinforced concrete internal support, and finishing the support construction of the section; (10) Repeating the steps (3) - (9) until the foundation pit bottom is constructed; and (11) binding the bottom plate steel bars and pouring bottom plate concrete.
Preferably, in the step (1), aiming at high slope construction, the excavator is used for building a temporary road so as to facilitate the construction machine to walk and construct on the slope; the width of the channel is 2-2.2 m, and the shape is Z-shaped.
In the step (2), after the channel construction is completed, the steel pipe pile machine is subjected to field construction, a drilling machine is adopted to drill holes, the holes are washed after the holes are formed, the steel pipe is placed in the holes, a grouting pipe is inserted, pressure grouting is carried out by a grouting machine, the pipe is pulled out while grouting, and the hole opening needs to be subjected to grouting.
In the step (3), the foundation pit earth excavation adopts partitioned layered balanced excavation, the excavation depth is not more than 1.5m each time, the section length is not more than 10m each time, and the construction is strictly forbidden; the method is characterized in that the excessive deviation of the supporting structure is prevented, the earthwork excavation extends from two ends to the middle, the earthwork excavation is performed in a partitioned layered mode during construction, the partitioned excavation length is not more than 15m, the excavation depth of each layer is matched with the position of a corresponding soil nail, and the super excavation depth is not more than 50cm below the position of the corresponding soil nail; and the last layer strictly forbids overdrawing.
Preferably, in the step (4), after the earth is excavated to a predetermined height, the excavated surface is immediately sprayed with concrete to protect the surface, thereby preventing the soil layer from loosening.
In the step (5), a drilling machine is adopted to drill holes, soil nails are arranged after the holes are cleared, and grouting is carried out uniformly by a grouting pump after main reinforcements of the soil nails are put in the holes; the soil nails incline downwards, and the included angle between the soil nails and the horizontal plane is 15 degrees.
Preferably, in the step (6), after the soil nails are fixed, the mesh is woven by adopting steel bars, the lap joint length of the steel bar mesh is not less than 10cm, and the mesh is firmly bound by using fire wires; every 1m on the surface layer net 2 Binding a cushion block to ensure that a gap of 2cm is reserved between the surface layer net and the soil slope of the foundation pit so as to ensure that a concrete protection layer of 2cm is reserved on the surface layer net and fully play the role of a steel plate net framework; after the net is hung, welding transverse reinforcing steel bars, and connecting all rod bodies of the soil nails with the reinforcing steel bars to form a complete framework by the rod bodies of the soil nails, the surface layer net and the reinforcing steel bars; spraying concrete according to regulation operation, spraying water and curing 2 hours after finishing surface layer construction according to construction weather environmental conditions.
In the step (7), all the steel bar joints are welded or mechanically connected and are effectively staggered, binding is forbidden, and the steel bar joints at the same section surface are not more than 50% of the total steel bar amount; the supporting bottom is paved with a cushion layer, has enough bearing capacity, and needs to be replaced, filled and fixed to prevent uneven settlement of the support if necessary under the condition of meeting soil with insufficient bearing capacity, such as silt.
In the step (8), a beam side die adopts a 15mm thick cladding wood plywood, and the die plate is reinforced by adopting upper and lower rows of pull rods to carry out bidirectional opposite pulling; the diagonal braces and the flat plates are connected with the main keels through fasteners, and in order to prevent slurry leakage during concrete pouring, sponge strips are additionally arranged at the bottom end of the inner side of the side die, so that the templates can reliably bear various loads of a supporting structure and construction.
In the step (9), the slump check is preferably carried out on each concrete vehicle, so that the slump of the concrete is controlled within the range of 180-220mm, the operation of the vibrating rod is required to achieve 'quick insertion and slow extraction', and the concrete is vibrated by adopting an inserted vibrator, so that the phenomenon of insufficient concrete vibration or die sinking caused by excessive vibration at one place is strictly prevented until the surface of the concrete is flooded and a large amount of bubbles are not generated.
The principle of the invention is as follows: the construction method is characterized in that a semi-reverse combined foundation pit supporting form is adopted for construction, in order to ensure the stability of a high slope under complex geological conditions, steel pipes are driven into three sides of a deep foundation pit excavation front foundation pit and concrete is poured into the three sides to serve as pre-supporting of foundation pit excavation, and then reverse construction is adopted for deep foundation pit construction. Under the condition of ensuring the stability of the high side slope, the construction mode simultaneously controls the deformation of the soil body around the deep foundation pit, and smoothly completes the construction of the deep foundation pit on the premise of ensuring the reasonable and economical structure of the foundation pit.
The invention has the following advantages:
(1) The invention has reasonable design and is suitable for deep foundation pit construction under the condition of high side slope of complex terrain. And the mechanical operation is adopted, the construction is rapid and flexible, the construction speed is high, and the construction period is short.
(2) Compared with the foundation pit supporting mode with higher rigidity, such as underground continuous walls and the like, the combined supporting structure is more suitable for the situation that grooving construction is difficult to carry out on a high slope and instability of the high slope possibly occurs.
(3) Compared with a steel sheet pile supporting form capable of being rapidly constructed, the supporting form is more suitable for a foundation pit which is positioned on a high slope and has a larger depth, and compared with the steel sheet pile foundation pit, the deformation of the combined supporting structure can be better controlled, and the stability of the high slope is maintained.
(4) Compared with the flexible supporting structure, the inner supporting structure is relatively more in needed inner supporting structure, more construction intersections have a certain influence, the overall stability control of the foundation pit and the high slope is less favorable, and the safety of the combined supporting structure can be effectively ensured.
(5) The combined support forms of the invention are all small-sized mechanical construction, the foundation pit construction has small influence on the stability of the high slope, and the small-sized mechanical energy is better suitable for narrower construction sites. Compared with the combined supporting structure, the combined supporting structure has the advantages of simple construction steps, low input cost and good economic effect.
(6) The combined support of the steel pipe cast-in-place pile, the grouting soil nails, the reinforced concrete support plate and the reinforced concrete inner support is adopted, the support depth is large, the safety is high, and the problems of high construction cost, inconvenient control, narrow construction space and the like of the existing deep foundation pit construction under the condition of high side slope of complex topography can be solved.
Drawings
Fig. 1 is a flow chart of the construction method of the present invention.
Figure 2 is a cross-sectional view of a composite foundation pit support.
Figure 3 is an overall cross-sectional view of a composite foundation pit support.
Fig. 4 is a three-dimensional schematic of a composite foundation pit support.
Fig. 5 is a schematic structural view of the foundation pit.
Wherein, 1 is the steel-pipe pile, 2 is slip casting soil nail, 3 is string net concrete facing layer, 4 is the capping crown beam, 5 is reinforced concrete barricade, 6 is a concrete supporting beam, 7 is string net reinforcing bar, 8 is support barricade reinforcing bar, 9 is high side slope, 10 is the bottom plate.
Detailed Description
The present invention will be described in further detail with reference to the following embodiments.
A construction method of a deep foundation pit under a high side slope condition comprises the following steps: (1) constructing a construction channel on a hillside; (2) At the high side slope, constructing a steel pipe pile corresponding to soil bodies outside three sides of the foundation pit; (3) The earthwork excavation is carried out in the foundation pit from top to bottom, the earthwork of the first section is directly excavated, the excavation of the earthwork of the other sections except the first section is completed by the support construction of the last section, and the detection is qualified; (4) After the earthwork of the section is excavated, concrete facing is sprayed on the surfaces of the soil bodies of the three faces corresponding to the foundation pit; (5) performing soil nailing construction in the soil layer facing the concrete guard; (6) After the soil nail construction is completed, constructing a net hanging and concrete spraying on the surface of the concrete facing; (7) binding reinforcing steel bars on the inner side of the net-hanging sprayed concrete; (8) setting up a template; (9) Pouring concrete, constructing a reinforced concrete support plate and a reinforced concrete internal support, and finishing the support construction of the section; (10) Repeating the steps (3) - (9) until the foundation pit bottom is constructed; and (11) binding the bottom plate steel bars and pouring bottom plate concrete. The method comprises the following steps:
(1) Construction of construction sidewalk
Firstly, combining the site situation, reasonably selecting lines and determining a reasonable turning radius. And then, a pile in a temporary road is tested, a mark is made by using a wood pile, each section is tested, collected measurement data is subjected to temporary road slope pulling design, after a reasonable longitudinal slope is determined, on-site lofting is carried out according to section data, a control pile is set up and protected by original ground joint measurement, the temporary road surface is 20cm thick brick residue broken stone and 10cm concrete, local soft soil (about 50 cm) in the temporary road area is excavated by adopting an excavator in a matching way, 20cm thick brick residue broken stone is paved after compaction and soil replacement, and a layer of 10cm C20 concrete is paved on a surface layer in a reciprocating way. The slope of the mountain in the side area of the pavement is anchored by spraying in consideration of the load of the temporary construction machinery construction and the transportation material on the pavement. The width of the passageway is about 2 meters, and the shape is similar to a Z shape.
(2) Steel pipe pile construction
After the pavement construction is completed, discharging the foundation pit side line and setting the pile position according to the design requirement, adopting a steel pipe pile machine to drill holes for construction, cleaning the holes and putting into a steel pipe after hole forming, ensuring that the steel pipe and a grouting pipe are inserted into the hole bottom, and carrying out grouting construction in time after the extension and lowering installation of the steel pipe is completed. The steel pipe pile is required to be placed into the pit at least 4 meters, and is phi 203 mm or 14mm, and the steel type Q235B is adopted. The invention discloses a gravity retaining wall at the top of a high slope, which is used for constructing double-row steel pipe piles at the top of the high slope in order to ensure the stability of the slope. The method comprises the following steps:
1) Piling a driving route of the steel pipe pile machine according to the step classification, wherein the driving route refers to the construction method of a mountain-surrounding highway, the width of each step of a design drawing is more than 2m, the width of a small excavator and the width of the small steel pipe pile machine are within 2m, a construction passageway is firstly made by the excavator, and the steel pipe pile machine can enter the ground for construction.
2) And (5) discharging the side line of the foundation pit and positioning the pile position according to the design requirement, installing a drilling machine to perform hole forming operation, and checking and protecting the pile. The technology adopts a dry pore-forming mode for drilling, and a drilling machine is used for accurately positioning on a pore-forming position according to the positioning of the micro pile. Placing the drilling machine at a designated position, placing horizontally, and preventing inclination; lifting the drill rod to the side of the drilling machine, starting the drilling machine, and slowly drilling; every 3m deep, the drill rod needs to be connected once until the designed effective depth is obtained. When the steel pipe is lengthened, the upper section and the lower section of steel pipe are connected by a sleeve.
3) After the steel pipe is put down, grouting is carried out in time, the grouting pipe is only connected to the steel pipe in the lower hole by a grouting machine, the connectors are in sealing connection, and the grouting pipe is conveyed by adopting a rubber pipe. Adopts disposable grouting (either grouting after pipe casting or grouting after pipe casting). Lifting 300mm after the grouting pipe is lowered to the bottom of the hole, and performing open grouting until the hole orifice emits pure slurry; grouting starts from the bottom of the hole, and grouting and pulling are performed simultaneously, so that the compactness of the slurry is ensured. And (3) after the slurry is precipitated and initially set, timely performing slurry supplementing treatment on the inner side and the outer side of the pipe wall to completely fill the pile hole. And (3) inserting a grouting pipe for pressure grouting, wherein the grouting strength is not less than 30MPa, and grouting and pipe drawing are performed simultaneously, and the orifice needs to be subjected to grouting. The cement slurry water cement ratio of the grouting cement in the steel pipe pile is 0.45-0.55, the construction of the steel pipe pile adopts the construction of a pile isolation, and the drilling construction of the adjacent pile can be carried out after the cement slurry strength of the adjacent pile reaches 70% of the design strength.
The steel pipe pile is anchored into the crown beam with the thickness of not less than 400mm, and residues, floating soil and accumulated water on the pile top must be cleaned before the crown beam is poured.
(3) Earthwork excavation
The earth excavation is carried out after the construction of all supporting members including steel pipe piles, soil nails, supporting beams and the like is finished and the construction is monitored to be qualified, and the next layer can be excavated.
Dividing and layering balanced excavation is adopted for foundation pit earth excavation, the excavation depth is not more than 1.5m each time, the section length is not more than 10m each time, and each section of construction is strictly forbidden; the method is characterized in that the excessive deviation of the supporting structure is prevented, the earthwork excavation extends from two ends to the middle, the earthwork excavation is performed in a partitioned layered mode during construction, the partitioned excavation length is not more than 15m, the excavation depth of each layer is matched with the position of a corresponding soil nail, and the super excavation depth is not more than 50cm below the position of the corresponding soil nail; and the last layer strictly forbids overdrawing.
The depth of each excavation of the earthwork is the bottom of a grouting soil nail or a supporting beam, and the concrete facing is hung on a net immediately after the excavation is completed, so that the stability of the excavated surface is ensured.
(4) Sprayed concrete facing
After the earthwork is excavated to a specified elevation, the excavated surface is immediately sprayed with concrete to protect the surface, so that the soil layer is prevented from loosening and the earthwork is prevented from collapsing.
The driver of the sprayer should operate according to the regulations, when the operation starts, air is supplied firstly, then the sprayer is started, and then the sprayer is fed, and when the spraying of the materials is finished, the sprayer is closed. The feeding to the sprayer should be continuous and uniform, and enough stock is kept in the hopper. And 2 hours after finishing the surface layer construction, carrying out sprinkling maintenance according to the construction weather environmental conditions.
(5) Grouting soil nail
1) Drilling holes at corresponding positions according to the design drawing and instructions of supervision engineers, and marking the positions of all soil nail holes by red paint. And (3) adopting pneumatic down-the-hole hammering to perform hole forming, wherein the hole forming angle is controlled during hole forming. The diameter of the hole is 130mm, the soil nails are arranged after the hole is cleared, the soil nails are HRB400, steel bars with phi 25mm and the length of the soil nails is 6-9 mm. The surface of the soil nail is derusted and painted with antirust paint, the orifice is wrapped by asphalt glass fiber cloth within the range of not less than 1m, and the number of layers is not less than two. The soil nails are manufactured in a reinforcing steel bar factory to be processed, treated and stored uniformly, and are conveyed to an installation working face to be directly installed.
2) After the main ribs of a batch of soil nails are put in, grouting is uniformly performed by a grouting pump, and a grouting pipe is required to be inserted to be 50cm away from the hole bottom, so that grouting quality is ensured. The plain cement paste is prepared by stirring Portland cement No. 42.5. The grouting adopts a soft plastic pipe to perform grouting from the bottom of the hole, and each hole is subjected to grouting 1-2 times after grouting. Grouting should adopt a hole bottom grouting method to ensure full grouting. The soil nails are adopted as full-length bonding type permanent soil nails, and the thickness of the protective layer is not less than 25mm. The strength of the grouting body is not lower than 20MPa, the grouting pressure is 0.5-0.8MPa, the cement ratio is 0.45-0.55 pure cement slurry, and the slurry compression resistance is not lower than 25MPa for 28 days. Meanwhile, a secondary grouting process is adopted, the secondary grouting adopts pure cement slurry, and the grouting pressure is 2.0-3.0MPa.
(6) Screen-sprayed concrete facing
And after the soil nails are fixed, immediately screening the excavated surface, and spraying concrete to protect the surface. The dowel bars are HRB400 grade steel bars, the distance between the surface layer steel bar meshes phi 10mm is 150mm multiplied by 150mm, and C20 fine stone suspicious soil with the thickness of 50mm is sprayed. The method comprises the following steps:
1) After the soil nails are fixed, the mesh is woven by adopting reinforcing steel bars with the diameter phi of 10mm, the mesh size is 150mm multiplied by 150mm, the overlap joint length of the reinforcing steel bars is not less than 10cm, and the reinforcing steel bars are firmly bound by fire wires. In addition, every 1m on the surface layer net 2 And a cushion block is bound, so that a gap of 2cm is reserved between the surface layer net and the soil slope of the foundation pit, a concrete protection layer of 2cm is reserved on the surface layer steel plate net, and the function of the steel plate net framework is fully exerted. After the net is hung, transverse reinforcing steel bars are welded, all soil nail rod bodies are connected with the reinforcing ribs, and the soil nail rod bodies, the surface layer net and the reinforcing ribs form a complete framework. Two reinforcing ribs are 16mm.
2) The driver of the sprayer should operate according to the regulations, when the operation starts, air is supplied firstly, then the sprayer is started, and then the sprayer is fed, and when the spraying of the materials is finished, the sprayer is closed. The feeding to the sprayer should be continuous and uniform, and enough stock is kept in the hopper. And 2 hours after finishing the surface layer construction, carrying out sprinkling maintenance according to the construction weather environmental conditions.
(7) Binding steel bar
Binding the reinforcing steel bars of the concrete support plate with the thickness of 600mm, adopting welding or mechanical connection for all the reinforcing steel bar connection, effectively staggering, prohibiting the binding, and preventing the reinforcing steel bar joint at the same section from exceeding 50% of the total reinforcing steel bar quantity. The support bottom should be paved with a cushion layer and has enough bearing capacity, and if necessary, replacement and filling are adopted to strengthen the support bottom so as to prevent the support from unevenly settling.
(8) Template setting up
The beam side mould adopts a 15mm thick cladding wood plywood, and the template reinforcement adopts upper and lower rows of pull rods to carry out bidirectional opposite pulling; the diagonal braces and the flat plates are connected with the main keels through fasteners, and in order to prevent slurry leakage during concrete pouring, sponge strips are additionally arranged at the bottom end of the inner side of the side die, so that the templates can reliably bear various loads of a supporting structure and construction.
(9) Concrete pouring
The slump check is carried out on the concrete of each vehicle, so that the slump of the concrete is controlled within the range of 180-220mm, the operation of the vibrating rod is required to be quickly inserted and slowly pulled out, the concrete is vibrated according to different points, the concrete at the material opening is firstly vibrated to form a natural flowing gradient, then the concrete is comprehensively vibrated, and the vibrating time, the moving distance and the inserting depth are strictly controlled. The concrete is vibrated by adopting an inserted vibrator, the vibrating distance is about 50cm, so that the phenomenon of die sinking caused by insufficient concrete vibration or excessive vibration at one place is strictly prevented until the surface of the concrete is flood and a large amount of bubbles are not generated. And curing the reinforced concrete baffle according to a conventional curing mode after pouring.
And constructing reinforced concrete support plates to form reinforced concrete retaining walls, and constructing concrete support beams to form inner supports.
(10) Construction to the bottom of foundation pit
And (3) to (9) are repeated, and when the concrete of the inner support and the support plate structure reaches the design strength, the earthwork excavation is repeated until the concrete is poured, and the foundation pit bottom is constructed.
(11) Construction of floors
Binding the bottom plate steel bars and pouring bottom plate concrete.
The invention improves and perfects the construction technology level on the premise of advanced, reasonable, economic and safe construction technology, and enables the engineering to smoothly finish the construction of the deep foundation pit.
The above examples are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above examples, and any other changes, modifications, substitutions, combinations, and simplifications that do not depart from the spirit and principle of the present invention should be made in the equivalent manner, and the embodiments are included in the protection scope of the present invention.
Claims (10)
1. The construction method of the deep foundation pit under the condition of high side slope is characterized by comprising the following steps:
(1) Constructing a construction channel on a hillside;
(2) At the high side slope, constructing a steel pipe pile corresponding to soil bodies outside three sides of the foundation pit;
(3) The earthwork excavation is carried out in the foundation pit from top to bottom, the earthwork of the first section is directly excavated, the excavation of the earthwork of the other sections except the first section is completed by the support construction of the last section, and the detection is qualified;
(4) After the earthwork of the section is excavated, concrete facing is sprayed on the surfaces of the soil bodies of the three faces corresponding to the foundation pit;
(5) Carrying out soil nailing construction in a soil layer facing the concrete guard;
(6) After the soil nail construction is completed, constructing a net hanging and concrete spraying on the surface of the concrete facing;
(7) Binding reinforcing steel bars on the inner side of the net-hanging sprayed concrete;
(8) Setting up a template;
(9) Pouring concrete, constructing a reinforced concrete support plate and a reinforced concrete internal support, and finishing the support construction of the section;
(10) Repeating the steps (3) - (9) until the foundation pit bottom is constructed;
(11) Binding the bottom plate steel bars and pouring bottom plate concrete.
2. The construction method of the deep foundation pit under the condition of high side slope according to claim 1, wherein the construction method comprises the following steps: in the step (1), aiming at high slope construction, the excavator is used for building a temporary road so as to facilitate the construction machinery to walk and construct on the slope; the width of the channel is 2-2.2 m, and the shape is Z-shaped.
3. The construction method of the deep foundation pit under the condition of high side slope according to claim 1, wherein the construction method comprises the following steps: in the step (2), after the pavement construction is completed, the steel pipe pile machine is subjected to field construction, a drilling machine is adopted to drill holes, the holes are washed after the holes are formed, the steel pipe is placed in the holes, a grouting pipe is inserted to perform pressure grouting by a grouting machine, the grouting is performed while the pipe is pulled out, and the hole opening needs to be subjected to grouting.
4. The construction method of the deep foundation pit under the condition of high side slope according to claim 1, wherein the construction method comprises the following steps: in the step (3), the foundation pit earth excavation adopts zoned layered balanced excavation, the excavation depth is not more than 1.5m each time, the section length is not more than 10m each time, and the construction is strictly forbidden; the method is characterized in that the excessive deviation of the supporting structure is prevented, the earthwork excavation extends from two ends to the middle, the earthwork excavation is performed in a partitioned layered mode during construction, the partitioned excavation length is not more than 15m, the excavation depth of each layer is matched with the position of a corresponding soil nail, and the super excavation depth is not more than 50cm below the position of the corresponding soil nail; and the last layer strictly forbids overdrawing.
5. The construction method of the deep foundation pit under the condition of high side slope according to claim 1, wherein the construction method comprises the following steps: in the step (4), after the earthwork is excavated to a specified elevation, the excavated surface is immediately sprayed with concrete to protect the surface, so that the soil layer is prevented from loosening.
6. The construction method of the deep foundation pit under the condition of high side slope according to claim 1, wherein the construction method comprises the following steps: in the step (5), a drilling machine is adopted to drill holes, soil nails are installed after the holes are cleared, and after main reinforcements of the soil nails are all placed in the holes, grouting is carried out uniformly by a grouting pump; the soil nails incline downwards, and the included angle between the soil nails and the horizontal plane is 15 degrees.
7. The construction method of the deep foundation pit under the condition of high side slope according to claim 1, wherein the construction method comprises the following steps: in the step (6), after the soil nails are fixed, the mesh is woven by adopting steel bars, the lap joint length of the steel bar mesh is not less than 10cm, and the mesh is firmly bound by fire wires; every 1m on the surface layer net 2 Binding a cushion block to ensure that a gap of 2cm is reserved between the surface layer net and the soil slope of the foundation pit so as to ensure that a concrete protection layer of 2cm is reserved on the surface layer net and fully play the role of a steel plate net framework; after the net is hung, welding transverse reinforcing steel bars, and connecting all rod bodies of the soil nails with the reinforcing steel bars to form a complete framework by the rod bodies of the soil nails, the surface layer net and the reinforcing steel bars; spraying concrete according to regulation operation, spraying water and curing 2 hours after finishing surface layer construction according to construction weather environmental conditions.
8. The construction method of the deep foundation pit under the condition of high side slope according to claim 1, wherein the construction method comprises the following steps: in the step (7), all the steel bars are connected by adopting welding or mechanical connection, are effectively staggered, are forbidden to be bound, and the steel bar joints at the same section of the surface are not more than 50% of the total steel bars; the support bottom should be paved with a cushion layer and has enough bearing capacity, and if necessary, replacement and filling are adopted to strengthen the support bottom so as to prevent the support from unevenly settling.
9. The construction method of the deep foundation pit under the condition of high side slope according to claim 1, wherein the construction method comprises the following steps: in the step (8), a beam side die adopts a 15mm thick cladding wood plywood, and the formwork reinforcement adopts upper and lower rows of pull rods to carry out bidirectional opposite pulling; the diagonal braces and the flat plates are connected with the main keels through fasteners, and in order to prevent slurry leakage during concrete pouring, sponge strips are additionally arranged at the bottom end of the inner side of the side die, so that the templates can reliably bear various loads of a supporting structure and construction.
10. The construction method of the deep foundation pit under the condition of high side slope according to claim 1, wherein the construction method comprises the following steps: in the step (9), each car of concrete is subjected to slump inspection, so that the slump of the concrete is controlled within the range of 180-220mm, the operation of a vibrating rod is required to be quickly inserted and slowly pulled, an inserted vibrator is adopted for concrete vibrating, the phenomenon of insufficient concrete vibrating or die sinking caused by excessive vibration at one place is strictly prevented until the surface of the concrete is overturned and a large amount of bubbles are not generated.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310671272.3A CN116556357A (en) | 2023-06-07 | 2023-06-07 | Construction method of deep foundation pit under high side slope condition |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310671272.3A CN116556357A (en) | 2023-06-07 | 2023-06-07 | Construction method of deep foundation pit under high side slope condition |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116556357A true CN116556357A (en) | 2023-08-08 |
Family
ID=87493057
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310671272.3A Pending CN116556357A (en) | 2023-06-07 | 2023-06-07 | Construction method of deep foundation pit under high side slope condition |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116556357A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117948163A (en) * | 2024-03-26 | 2024-04-30 | 洛阳展尚建筑工程有限公司 | Supporting frame for preventing tunnel from collapsing |
-
2023
- 2023-06-07 CN CN202310671272.3A patent/CN116556357A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117948163A (en) * | 2024-03-26 | 2024-04-30 | 洛阳展尚建筑工程有限公司 | Supporting frame for preventing tunnel from collapsing |
| CN117948163B (en) * | 2024-03-26 | 2024-06-11 | 洛阳展尚建筑工程有限公司 | Supporting frame for preventing tunnel from collapsing |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112554177B (en) | Construction method of ultra-long small-diameter cast-in-situ bored pile | |
| CN112502777B (en) | Method for treating tunnel inrush roof collapse and door closing | |
| CN109595004B (en) | Tunnel two-expansion four-expansion excavation method | |
| CN111576431A (en) | Excavation method for foundation pit of four-layer subway station | |
| CN113847050B (en) | Construction method of ultra-long highway tunnel in lava mountain area | |
| CN108952804B (en) | Tailing filling retaining wall for blocking mining roadway of goaf to be filled and construction method | |
| CN112575670B (en) | T-shaped rigid frame bridge suitable for tunnel to pass through giant karst cave and construction technology thereof | |
| CN111997624A (en) | Shallow-buried large-section underground excavation rectangular tunnel construction method | |
| WO2023077552A1 (en) | Construction method for foundation pit enclosure and earth excavation | |
| CN114263168A (en) | Construction method of rock-socketed diaphragm wall of stratum water-stopping enclosure structure | |
| CN116556357A (en) | Construction method of deep foundation pit under high side slope condition | |
| CN216194901U (en) | Unloading plate type retaining wall structure for large-span underground garage | |
| CN112854254A (en) | Construction method for existing railway field level subgrade support in deep artificial waste slag area | |
| CN110258600B (en) | Vertical cofferdam construction method suitable for deepwater area | |
| CN111733824A (en) | Deep foundation pit supporting structure | |
| CN109024670B (en) | Underground comprehensive pipe gallery protection and reinforcement system penetrating through buried high-voltage cable and reinforcement method | |
| CN113898007B (en) | Semi-inverse construction method for long-span corridor structure along street | |
| CN112854841B (en) | Civil construction structure construction method of bottom mud treatment plant | |
| CN114991165A (en) | Construction method for subway deep foundation pit adjacent to railway business line | |
| CN115030731A (en) | Pilot tunnel construction method in cross tunnel engineering | |
| CN114411761A (en) | Advanced pre-support system for planned subway tunnel during construction of newly-built building and pre-support construction method | |
| CN113338340A (en) | Reverse construction method for vertical shaft ensuring normal use of existing pipeline | |
| CN113638443A (en) | Construction process of underground comprehensive pipe gallery | |
| CN113202110A (en) | Construction method for supporting and protecting finite space railway bridge and culvert prefabricated foundation pit | |
| CN112627002A (en) | Continuous beam bridge suitable for tunnel to pass through giant karst cave and construction technical method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| CB03 | Change of inventor or designer information |
Inventor after: Liu Shihui Inventor after: He Jiawei Inventor after: Yang Wucheng Inventor after: Qian Zhenhua Inventor after: Peng Weiping Inventor after: Liang Wenjin Inventor after: Wen Zhongyi Inventor after: He Chenfei Inventor after: Chen Keran Inventor after: Huang Huajian Inventor after: Wei Yusen Inventor after: Zhang Hanlin Inventor before: Liu Shihui Inventor before: Qian Zhenhua Inventor before: Liang Wenjin Inventor before: He Chenfei Inventor before: Chen Keran Inventor before: Huang Huajian Inventor before: Wei Yusen Inventor before: Zhang Hanlin Inventor before: He Jiawei Inventor before: Yang Wucheng |
|
| CB03 | Change of inventor or designer information |