CN117702815B - Symmetrical extension construction method for lateral open cut of existing underground space - Google Patents
Symmetrical extension construction method for lateral open cut of existing underground space Download PDFInfo
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- CN117702815B CN117702815B CN202311804079.9A CN202311804079A CN117702815B CN 117702815 B CN117702815 B CN 117702815B CN 202311804079 A CN202311804079 A CN 202311804079A CN 117702815 B CN117702815 B CN 117702815B
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- 238000010276 construction Methods 0.000 title claims abstract description 103
- 239000002689 soil Substances 0.000 claims abstract description 44
- 238000009412 basement excavation Methods 0.000 claims abstract description 20
- 238000007599 discharging Methods 0.000 claims abstract description 10
- 230000003014 reinforcing effect Effects 0.000 claims abstract description 3
- 239000010410 layer Substances 0.000 claims description 33
- 230000002787 reinforcement Effects 0.000 claims description 14
- 238000000034 method Methods 0.000 claims description 10
- 239000004814 polyurethane Substances 0.000 claims description 9
- 229920002635 polyurethane Polymers 0.000 claims description 9
- 229910000831 Steel Inorganic materials 0.000 claims description 7
- 230000035515 penetration Effects 0.000 claims description 7
- 239000010959 steel Substances 0.000 claims description 7
- 239000003973 paint Substances 0.000 claims description 6
- 239000000126 substance Substances 0.000 claims description 6
- 238000005266 casting Methods 0.000 claims description 5
- 239000011248 coating agent Substances 0.000 claims description 5
- 238000000576 coating method Methods 0.000 claims description 5
- 239000011241 protective layer Substances 0.000 claims description 5
- 239000004575 stone Substances 0.000 claims description 5
- 239000011247 coating layer Substances 0.000 claims description 4
- 239000012754 barrier agent Substances 0.000 claims description 2
- 239000002199 base oil Substances 0.000 claims description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 14
- 238000005520 cutting process Methods 0.000 description 8
- 238000005553 drilling Methods 0.000 description 7
- 230000001360 synchronised effect Effects 0.000 description 6
- 239000002002 slurry Substances 0.000 description 5
- 238000010008 shearing Methods 0.000 description 4
- 239000003795 chemical substances by application Substances 0.000 description 3
- 238000004140 cleaning Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000007667 floating Methods 0.000 description 3
- 238000005065 mining Methods 0.000 description 3
- 239000011083 cement mortar Substances 0.000 description 2
- 238000005336 cracking Methods 0.000 description 2
- 230000018109 developmental process Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000011229 interlayer Substances 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 239000004593 Epoxy Substances 0.000 description 1
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- 239000000428 dust Substances 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000004570 mortar (masonry) Substances 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 230000011218 segmentation Effects 0.000 description 1
- 239000011257 shell material Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
- 238000004078 waterproofing Methods 0.000 description 1
- 238000009736 wetting Methods 0.000 description 1
- 238000005491 wire drawing Methods 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
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D17/00—Excavations; Bordering of excavations; Making embankments
- E02D17/02—Foundation pits
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D17/00—Excavations; Bordering of excavations; Making embankments
- E02D17/02—Foundation pits
- E02D17/04—Bordering surfacing or stiffening the sides of foundation pits
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D3/00—Improving or preserving soil or rock, e.g. preserving permafrost soil
- E02D3/12—Consolidating by placing solidifying or pore-filling substances in the soil
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- 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
-
- 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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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A30/00—Adapting or protecting infrastructure or their operation
- Y02A30/60—Planning or developing urban green infrastructure
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- Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- Structural Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Civil Engineering (AREA)
- Paleontology (AREA)
- General Life Sciences & Earth Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Agronomy & Crop Science (AREA)
- Soil Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Working Measures On Existing Buildindgs (AREA)
Abstract
The invention relates to a symmetrical extension construction method for lateral open cut of an existing underground space, which comprises the following steps: grouting and reinforcing soil in a region within a first set range of the periphery of the foundation pit; constructing guard piles on the periphery of the foundation pit; before excavation of a foundation pit, carrying out slope discharging excavation and soil unloading on the covered soil in a second set range on two sides of the top of the existing structure; synchronously and symmetrically excavating foundation pits on two sides of the existing structure; after the foundation pit is excavated, synchronously constructing an extension structure in the foundation pit at two sides; performing side wall connection construction between the extension structure and the existing structure, and performing waterproof construction on connection positions of the extension structure and the existing structure after connection construction is completed; the construction method of the invention solves the problems faced by open cut extension construction.
Description
Technical Field
The invention relates to the technical field of underground space, in particular to a lateral open cut symmetrical extension construction method of an existing underground space.
Background
The statements herein merely provide background information related to the present disclosure and may not necessarily constitute prior art.
The underground space comprises urban underground space, mining underground space and the like, the mining underground space mainly comprises structures such as a roadway and the like, a concrete structure of the mining underground space is disclosed in a patent CN202010274746.7 (corresponding publication CN111425216A, publication number CN 111425216B), the concrete structure comprises a roadway, a supporting structure and the like, the urban underground space mainly comprises underground space for subway rail transit, the underground space comprises a subway tunnel, a subway station and the like, and urban underground space construction gradually becomes a new requirement for urban development and is rapidly increased. Early underground spaces are distributed in multiple points, and along with urban development and urban population increase, a large number of existing underground spaces cannot meet the increasing operation demands gradually, and the existing underground structures are required to be enlarged and expanded. The existing structure adopts a lateral open-cut method to expand the volume and the expansion, has more advantages than the underground-cut construction, and becomes a preferred construction mode.
In open cut lateral extension construction, the mutual influence between the extension structure and the existing structure is larger, a close-distance open cut foundation pit can cause lateral sliding of the existing structure and lateral landslide of a top soil body, normal use of the existing structure is influenced, influence of the lateral open cut construction on the existing structure is reduced, lateral sliding of the existing structure and lateral landslide of the top soil body are controlled, and meanwhile integrity of the existing structure after the existing structure is communicated with the extension structure is ensured, so that the open cut lateral extension construction is a difficult problem faced by existing underground structure lateral expansion extension construction at present.
Disclosure of Invention
Aiming at the defects existing in the prior art, the invention aims to provide a symmetrical extension construction method for lateral open cut of the existing underground space, which reduces the influence of a laterally symmetrical open cut foundation pit on the existing structure, controls the bulge and lateral sliding of the existing structure and ensures the integrity of the existing structure after the existing structure is communicated and connected with the extension structure.
In order to achieve the above object, the present invention is realized by the following technical scheme:
The embodiment of the invention provides a symmetrical extension construction method for lateral open cut of the existing underground space, which comprises the following steps:
grouting and reinforcing soil in a region within a first set range of the periphery of the foundation pit;
Constructing guard piles on the periphery of the foundation pit;
before excavation of a foundation pit, carrying out slope discharging excavation and soil unloading on the covered soil in a second set range on two sides of the top of the existing structure;
synchronously and symmetrically excavating foundation pits on two sides of the existing structure;
After the foundation pit is excavated, synchronously constructing an extension structure in the foundation pit at two sides;
performing side wall connection construction between the extension structure and the existing structure, and performing waterproof construction on connection positions of the extension structure and the existing structure after connection construction is completed;
and carrying out synchronous backfill construction on the extension structure and the existing structure.
Optionally, when grouting reinforcement is performed, the distance between the grouting holes and the existing structure is not smaller than 2m.
Optionally, the fender post adopts the bored concrete pile, and during the construction, adopts the manual work to dig the hole to the fender post that has the structure in the third settlement scope, and to the fender post that has the second settlement scope outside, the part that has above the structure bottom surface adopts the manual work to dig the hole, and the part that has below the structure bottom surface adopts to dig soon the drilling.
Optionally, when the top of the existing structure is used for slope discharging, firstly, mechanically breaking the pavement structure above the existing structure, and then manually cleaning the soil covered in a second set range on the two sides above the existing structure to realize slope discharging and soil discharging;
Further, when the thickness of the covering soil at the top of the existing structure is larger than 2m, slope protection treatment is carried out on the covering soil which is not cleaned at the top of the existing structure.
Optionally, when the synchronous symmetrical excavation of existing structure both sides foundation ditch, real-time supervision both sides foundation ditch excavate the degree of depth for both sides foundation ditch bottom surface is high Cheng Chaxiao relatively in 1m.
Optionally, before pouring the extension structure, constructing a grounding grid and a cushion layer on the bottom surface of the foundation pit, and then pouring the extension structure, wherein a connection space is reserved between the extension structure and the existing structure during construction;
Further, after the construction of the top plate of the extension structure is completed, a temporary section steel support is arranged between the top plate and the bottom plate of the extension structure after the construction is completed.
Optionally, the concrete steps of performing the side wall connection construction between the extension structure and the existing structure are as follows:
Breaking the part of the side wall of the existing structure, which corresponds to the newly-built upright post of the extension structure;
After the construction, constructing an upper joist corresponding to the newly-built upright post in the construction area, continuously casting and constructing a lower joist along the longitudinal overall length of the extension structure, and then constructing the newly-built upright post between the lower joist and the upper joist;
after the construction of the new upright posts is completed, the side wall parts of the existing structure corresponding to the areas between two adjacent new upright posts are removed in sequence, then the upper joists corresponding to the areas between the new upright posts are constructed, and a plurality of upper joists are connected into an integral girder structure.
Optionally, before pouring the upper joist and the lower joist, constructing a shearing-resistant chemical anchor bolt at a connection position of the existing structure, wherein after pouring the upper joist and the lower joist, the shearing-resistant chemical anchor bolt is arranged between the upper joist, the lower joist and the existing structure;
Further, the upper joist is of a C-shaped structure, and the end part of a top plate of the existing structure is embedded into the upper joist;
optionally, grouting pipes are reserved in the upper joist and the lower joist.
Optionally, the specific steps of the waterproof construction at the connection position are as follows:
coating cold base oil or moisture barrier agent on the top surface of the connection position of the existing structure and the extension structure;
Then coating a polyurethane waterproof paint layer;
then a PE film is paved on the surface of the polyurethane waterproof coating layer;
Then a PVC root penetration resistant layer is paved on the surface of the PE film;
And finally paving a fine stone concrete protective layer.
The beneficial effects of the invention are as follows:
1. According to the construction method, before the foundation pit is excavated, grouting reinforcement is carried out on the soil body in the area with the first range set on the periphery of the foundation pit, then slope dumping excavation soil discharging is carried out on the soil body in the second set range on the two sides of the top of the existing structure, lateral sliding of the existing structure and lateral sliding of the soil body on the top of the existing structure can be prevented, normal use of the existing structure is guaranteed, and influence of lateral open excavation construction on the existing structure is reduced.
2. According to the construction method, the guard piles of the foundation pit are formed by combining manual hole digging and rotary hole digging, so that disturbance of drilling machinery and additional load to an existing structure is reduced, and influence of lateral open-cut construction on the existing structure is further reduced.
3. According to the construction method, synchronous symmetrical excavation is adopted for the foundation pits at the two sides of the existing structure, the relative elevation difference of the bottom surfaces of the foundation pits at the two sides is not smaller than 1 meter, and the phenomenon that the soil pressure at the two sides of the existing structure is uneven can be prevented from causing position deviation or structural deformation to the existing structure.
4. According to the construction method, the upper joist adopts the C-shaped structure, and the top plate of the existing structure is embedded into the C-shaped structure, so that the upper joist is tightly meshed with the top plate of the existing structure, the integrity of the structure at the connection position is improved, and the side wall of the existing structure is safer to dismount.
5. According to the construction method, the waterproof layer formed by combining the polyurethane waterproof coating layer, the PE film, the PVC root penetration resistant layer, the fine stone concrete protective layer and grouting is adopted, after the existing structure and the extension structure are backfilled, the whole waterproof layer is in a pressed state, interlayer cracking caused by overlapping of the waterproof layer can be effectively avoided, the possibility of failure of a waterproof system is further reduced, grouting pipes are reserved for the upper joist and the lower joist, grouting backfilling can be carried out if a water leakage phenomenon occurs after construction, and the waterproof effectiveness among the structures is fully ensured.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention.
FIG. 1 is a flow chart of the construction method of embodiment 1 of the present invention;
FIG. 2 is a schematic view of grouting reinforcement area and fender pile constructed in accordance with embodiment 1 of the present invention;
FIG. 3 is a top view of a grouting reinforcement zone and fender piles constructed in accordance with example 1 of the present invention;
FIG. 4 is a schematic diagram of the top unloading of the existing station in step 3 of example 1 of the present invention;
FIG. 5 is a schematic illustration of excavation of a foundation pit according to embodiment 1 of the present invention;
FIG. 6 is a schematic diagram of the construction of the extended structure according to embodiment 1 of the present invention;
FIG. 7 is a schematic view of two adjacent newly built columns during the side wall connection construction of embodiment 1 of the present invention;
FIG. 8 is a schematic diagram of a side wall connection construction according to embodiment 1 of the present invention;
FIG. 9 is a schematic view of a waterproof layer according to example 1 of the present invention;
Wherein, 1, the existing structure, 2, guard piles, 3, grouting reinforcement areas, 4, foundation pit areas, 5, the existing structure stratum, 6, earthing, 7, a second setting range, 8, water-retaining walls, 9, an extension structure, 10, temporary section steel supports, 11, 12, side walls, 13, middle plates, 14, replacement joists, 15, newly built upright posts, 16, bottom plates, 17, top plates, 18, shearing-resistant chemical anchors, 19, grouting pipes, 20, PVC root system penetration resistant layers and 21, fine stone concrete protective layers.
Detailed Description
For convenience of description, the words "upper" and "lower" in the present invention, if they mean only the directions of the words corresponding to the upper and lower directions of the drawings, are not limited to the directions, but are merely for convenience of description and simplification of description, and do not indicate or imply that the apparatus or element to be referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention.
Example 1
The embodiment provides a symmetrical extension construction method for lateral open cut of an existing underground space, wherein the existing structure is an existing station, as shown in fig. 1, and the method comprises the following steps:
Step 1: as shown in fig. 2 to 3, the earth surface grouting reinforcement is performed on the soil body in the foundation pit area 4 and the area within the first set range of the periphery of the foundation pit area, and a grouting reinforcement area 3 is formed in the existing structural stratum 5.
In the region of first settlement scope for foundation ditch periphery 5m, the scope that the grouting reinforcement can be set up according to actual need to the skilled person, through carrying out grouting reinforcement, can increase the stability of soil body.
In this embodiment, in order to ensure that the construction of the grouting holes does not affect the existing structure 1 when the grouting holes are drilled, the distance between the grouting holes and the existing structure is not less than 2m, and the grouting holes are arranged according to the grouting reinforcement range.
After the construction of the grouting holes is completed, placing the grouting sleeve valve pipe into the grouting holes along the center of the drill bit, pulling out the drill bit, injecting the sealing shell material, when the strength reaches 0.3Mpa, starting grouting for the first round, wherein the slurry dosage is 50% of the designed grouting quantity, grouting is performed from bottom to top, after the initial setting of the slurry for the first time is 12 hours, starting grouting for the second round, wherein the slurry dosage for the second round is 30% of the designed grouting quantity, after the initial setting of the slurry for the second round is 12 hours, starting grouting for the third round, and the slurry dosage is 20% of the designed grouting quantity.
Step 2: and after the earth surface grouting reinforcement is completed, constructing the fender post 2 of the foundation pit.
In this embodiment, the fender post 2 adopts the bored concrete pile, sets up along the foundation ditch edge, and the foundation ditch does not set up fender post 2 with the edge that existing structure 1 meets, and the construction of bored concrete pile adopts artifical hole digging and mechanical drill to dig soon and bore the scheme that combines together.
For the cast-in-place pile in the third set range area around the existing structure, manual hole digging and pile casting are adopted, and in this embodiment, the third set range area is an area within 5m and 5m from the existing structure.
The method for manually digging holes and pouring the poured pile is only required to be adopted by the existing construction method, and detailed description is omitted here.
For the bored concrete pile outside the range of five meters from the existing structure 1, when a pile hole is constructed, the part above the bottom surface of the existing structure 1 is manually dug, the rest part is rotationally dug and drilled, namely, the hole is manually dug to the depth that the hole depth reaches the bottom surface of the existing structure, and then the rest part is rotationally dug and drilled by a drilling machine.
The methods of manual drilling and rotary drilling are performed by conventional construction methods and are not described in detail herein.
After the pile hole construction is completed, the existing construction method is adopted to perform the pouring of the pouring pile.
By adopting the construction method, the fender post 2 reduces disturbance of drilling machinery and additional load to the existing structure, and further reduces influence of lateral open cut construction to the existing structure.
After the construction of the filling pile is completed, a water retaining wall 8 is constructed on the earth surface at the corresponding position of the filling pile, and the water retaining effect is achieved.
Step 3: as shown in fig. 4, before the foundation pit is excavated, the covering soil 6 in the second set range 7 on the two sides of the top of the existing structure 1 is subjected to slope-placing excavation soil unloading, so that the top unloading of the existing station is realized.
In this embodiment, the second setting range 7 may be determined according to actual engineering requirements, and specifically includes the following steps:
step 3.1: and breaking the pavement structure at the upper part of the existing structure by using mechanical equipment.
And 3.2, after the pavement structure is broken, manually excavating and removing the covering soil in a second set range on the two sides of the top of the existing structure, and then releasing slopes on the two sides of the reserved covering soil.
Further, when the thickness of the covering soil above the existing structure 1 is greater than 2m, the covering soil 6 remained at the top of the existing structure 1 is subjected to slope protection treatment, and the slope protection treatment method is only required to adopt the existing construction method, which is not described in detail herein.
In the embodiment, the soil is unloaded and the slope is released through earth surface grouting reinforcement and excavation above the existing structure, so that the lateral sliding of the existing structure and the lateral sliding of soil body at the top of the existing structure can be prevented, the normal use of the existing structure is ensured, and the influence of the lateral open cut construction on the existing structure is reduced.
Step 4: as shown in fig. 5, synchronous symmetrical excavation is performed on foundation pits on both sides of the existing structure 1.
In this embodiment, the synchronous symmetrical excavation of segmentation, layering can be carried out to existing structure both sides, real-time supervision both sides foundation ditch excavation degree of depth, and the relative high Cheng Chaxiao in 1 meter in the foundation ditch bottom surface of tight control both sides prevents to cause position offset or structural deformation to existing structure because of the soil pressure inequality in both sides.
In this embodiment, the foundation pit area within the range of 2m adjacent to the existing structure is excavated manually, the foundation pit area outside the range of 2m of the existing structure is excavated by mechanical equipment according to the standard section foundation pit, the excavation is completed by adopting the prior art, and in this section, the detailed description is given, in order to ensure that the existing structure does not laterally displace during the excavation of the foundation pit, the excavation of the foundation pit adopts a form of supporting before excavating, and the deformation is reduced.
Step 5: as shown in fig. 6, after the foundation pit is excavated, the extension structure is synchronously constructed in the foundation pit at two sides, and pouring of the main body of the extension structure is completed.
Specifically, the ground net and the cushion layer can be constructed on the bottom pit surface of the foundation pit after the foundation pit can be excavated to the designed elevation, and the existing construction method is adopted, and the detailed description is omitted here.
Then, at the construction of the extension structure 9, firstly pouring a bottom plate 16 of the extension structure 9, then constructing a waterproof layer of the bottom plate 16, dismantling a template, pouring structural columns and side walls, constructing a side wall waterproof layer after the side walls are poured, then pouring the extension structure 9 in sections along the longitudinal direction, pouring in layers along the vertical direction, pouring in a construction method from bottom to top, pumping waterproof concrete during pouring, continuously pouring, and tamping by using a high-frequency vibrator after pouring.
When the top plate 17 and the bottom plate 16 are poured, a connection space is reserved between the end part, which is close to the side wall of the existing structure 1, and the existing structure 1.
After the construction of the top plate 17 is completed, a plurality of temporary section steel supports 10 are provided between the top plate and the bottom plate of the extension structure in order to prevent collapse of the top plate of the extension structure.
Specifically, after the pouring of the top plate 17 is completed and the design strength is reached, the scaffold between the top plate 17 and the bottom plate 16 for supporting the top plate pouring template is removed, and a row of scaffolds closest to the existing structure is left to serve as temporary section steel support.
Step 6: as shown in fig. 7 to 8, the side wall connection construction is performed between the extension structure 9 and the existing structure 1, specifically including the following steps:
Step 6.1: the side wall portion of the existing structure 1 corresponding to the newly built column 15 of the extension structure 9 is broken, and in this embodiment, the side wall 12 broken in this step is defined as a first side wall portion.
In this embodiment, the upper portion of the first side wall portion is cut by using a water drill, so as to reduce the influence of breaking construction on operation of the existing structure, and the lower portion of the first side wall portion is broken by using a rope saw cutting process, and when the breaking is performed, the breaking is performed from the outer side to the inner side of the existing structure 1 in sequence from top to bottom.
Step 6.2: in the breaking area of step 6.1, pouring an upper joist between the connection end of the top plate 9 of the extension structure and the top plate of the existing structure 1 after the first side wall part is broken, pouring the upper joist only at the corresponding position of the breaking area, pouring a lower joist between the bottom plate of the extension structure and the middle plate of the existing structure 1, wherein the lower joist is longitudinally and continuously arranged along the extension structure, and the upper joist and the lower joist jointly form a joist exchanging 14.
The section of the upper joist is of a C-shaped structure and is provided with an embedded groove, and the connection end of the top plate 11 of the existing structure 1 is embedded into the embedded groove of the upper joist.
The lower joist is rectangular in cross section and is arranged between the bottom plate 16 of the extension structure and the connecting end of the middle plate 13 of the existing structure.
In this embodiment, the upper joist adopts C type structure, and inside the roof 11 embedding C type structure of existing structure 1 for upper joist closely interlock with the roof 11 of existing structure 1, increased the wholeness of position structure of plugging into, make the dismantlement of existing structure side wall safer.
Before pouring the upper joist and the lower joist, removing floating paste and sundries from the end surfaces of the connection ends of the top plate 17 and the bottom plate 16 of the extension structure 9, then brushing a concrete interface treatment agent and waterproof paint, paving cement mortar, removing the floating paste on the connection end surface of the existing structure 1, cleaning and airing, then spraying epoxy mortar, placing a shearing-resistant chemical anchor bolt 18 at the connection end of the existing structure 1, and after the connection ends of the extension structure 9 and the existing structure 1 are treated, then pouring newly-built upright posts 15 between the upper joist and the lower joist and between the upper joist and the lower joist.
When the upper joist and the lower joist are poured, a grouting pipe 19 is reserved in the upper joist and the lower joist, grouting backfilling can be performed if water leakage occurs after construction, and the waterproof effectiveness between structures is fully ensured.
And 6.3, after the strength of all newly-built upright posts 15, the upper joists and the lower joists reaches 100%, the dismantling of the rest second side wall parts of the side wall 12 of the existing structure 1 is completed. The second side wall portion is an existing side wall portion corresponding between two adjacent newly-built columns 15.
When the second side wall parts of two adjacent newly-built upright posts 15 are removed, the second side wall parts are removed in groups, preferably, each 3m is a group, and after the second side wall parts in the 3m area are broken, the corresponding upper joists are constructed.
When the second side wall part is removed, the upper part is broken by a water drill, the lower part is broken by a rope saw cutting process, and the second side wall part is removed to carry out lifting equipment configuration according to the load of the removing structure. The cutting size of each block is not more than 0.5t in principle, and the cutting size of the single concrete block can be properly adjusted according to the actual situation in site construction. And drilling holes on the part of the concrete structure to be removed by adopting a water drill before cutting by the rope saw, and penetrating a steel wire rope to perform anti-falling reinforcement. And after the hoisting equipment is in place, starting cutting, and hoisting away from the working surface after finishing cutting. The construction and waste water and waste residue cleaning and outward transportation are all carried out in the extension structure, and the construction electricity and water are all introduced into the self-extension structure. The spray system is required to be installed in the extension structure, so that the dust settling effect is achieved to the greatest extent.
The construction of the upper joist between 15 of two newly built upright posts is completed by adopting the construction method of the upper joist in the step 6.2, which is not repeated herein, because the lower joist is integrally poured, the problem of connection does not exist, when the adjacent upper joists are connected, firstly, the end face of the upper joist which is constructed in advance is cleaned of floating paste and sundries, then the concrete interface treating agent and the waterproof paint are coated, then the cement mortar is paved, and then the upper joist which is constructed after pouring is carried out.
After the construction of all the upper joists is completed, all the upper joists are connected to form a whole beam. The lower joist is integrally cast in step 6.2.
Step 7: as shown in fig. 9, the construction of waterproofing is performed at the junction position of the extension structure 9 and the existing structure 1, specifically comprising the steps of:
Step 7.1: the top plate 17 of the extension structure and the upper surface of the upper joist are coated with a cold primer or a moisture-proof agent on the upper surface of the connection position of the top plate 11 of the existing structure 1.
Step 7.1: then a polyurethane waterproof paint layer, preferably a high-quality single-component polyurethane paint with the thickness of 2.5mm is painted.
Step 7.2: and paving a PE film on the surface of the polyurethane waterproof coating layer. The overlap joint length of the PE film and the waterproof layer of the existing structure 1 is not less than 100mm.
Step 7.3: and a PVC root penetration resistant layer 20 is paved on the surface of the PE film to prevent plant rootstalk damage, and preferably, the PVC root penetration resistant layer 20 is an existing PVC film.
And 7.4, finally paving a fine stone concrete protective layer 21 with the thickness of 100mm to form the whole waterproof layer. The method of the embodiment sets an external waterproof system and construction technology of the communicated joint part of the PVC root penetration resistant layer, the PE film, the polyurethane waterproof coating and grouting, and after the existing structure and the extension structure backfill soil bodies in a layered manner and compact, the whole waterproof layer at the joint part of the existing structure and the extension structure is in a pressed state, so that interlayer cracking caused by overlapping of the waterproof layer can be effectively avoided, and the possibility of failure of the waterproof layer is further reduced. Grouting pipes are reserved on the upper joist and the lower joist at the joint, grouting backfilling can be performed if water leakage occurs after construction, and waterproof effectiveness among structures is fully ensured.
Step 8: and after the waterproof layer construction is completed, synchronous backfilling construction is carried out on the extension structure and the existing structure.
The top plate sundries of the existing structure 1 and the extension structure 9 are cleaned up before filling, whether the quality of backfill is sundries or not is checked, whether the grain size meets the regulation or not, and whether the water content of the backfill is in a controlled range or not is checked, if the water content is higher, the measures of scarification, airing or even dry soil doping can be adopted, if the water content on the backfill is lower, the measures of sprinkling water in advance, wetting and the like can be adopted. Backfill should be paved layer by layer, and the thickness of each layer should be determined according to the soil property, compactness requirement and machine performance, and each layer is paved and then raked. Each layer is backfilled with at least three ramming passes and water casting is strictly forbidden to sink the soil. After each layer of backfill soil is compacted, ring cutting sampling is carried out according to the specification, and the mass density of dry soil is measured; and after the requirement is met, paving the soil on the upper layer. After filling, carrying out surface wire drawing leveling, and leveling according to wires at places exceeding the standard elevation; and (3) tamping the soil at the place lower than the standard elevation to finish backfilling construction.
By adopting the construction method of the embodiment, the influence of the lateral open cut extension construction on the existing structure is greatly reduced, and the difficult problem faced by the lateral capacity-increasing extension construction of the existing underground structure is solved.
The above description is only of the preferred embodiments of the present application and is not intended to limit the present application, but various modifications and variations can be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.
Claims (13)
1. The construction method for symmetrically expanding the lateral open cut of the existing underground space is characterized by comprising the following steps of:
grouting and reinforcing soil in a region within a first set range of the periphery of the foundation pit;
Constructing guard piles on the periphery of the foundation pit;
before excavation of a foundation pit, carrying out slope discharging excavation and soil unloading on the covered soil in a second set range on two sides of the top of the existing structure;
synchronously and symmetrically excavating foundation pits on two sides of the existing structure;
After the foundation pit is excavated, synchronously constructing an extension structure in the foundation pit at two sides;
performing side wall connection construction between the extension structure and the existing structure, and performing waterproof construction on connection positions of the extension structure and the existing structure after connection construction is completed;
Backfilling construction is carried out on the expanded structure and the existing structure synchronously;
the first setting range is within a region of 5m of the periphery of the foundation pit;
the second setting range is determined according to actual engineering requirements;
the concrete steps of the side wall connection construction between the extension structure and the existing structure are as follows:
Breaking the part of the side wall of the existing structure, which corresponds to the newly-built upright post of the extension structure;
After the construction, constructing an upper joist corresponding to the newly-built upright post in the construction area, continuously casting and constructing a lower joist along the longitudinal overall length of the extension structure, and then constructing the newly-built upright post between the lower joist and the upper joist;
after the construction of the new upright posts is completed, the side wall parts of the existing structure corresponding to the areas between two adjacent new upright posts are removed in sequence, then the upper joists corresponding to the areas between the new upright posts are constructed, and a plurality of upper joists are connected into an integral girder structure.
2. The construction method for open cut symmetrical extension of the existing underground space according to claim 1, wherein the distance between the grouting holes and the existing structure is not less than 2m during grouting reinforcement.
3. The method for symmetrically expanding the lateral open cut of the existing underground space according to claim 1, wherein the guard piles are cast-in-place piles, manual hole digging is adopted for the guard piles in a third setting range of the existing structure during construction, manual hole digging is adopted for the guard piles outside the second setting range, and rotary hole digging is adopted for the parts above the bottom surface of the existing structure;
the third set range region is a region within a range of 5m and 5m from the existing structure.
4. The method for symmetric open cut construction of the existing underground space according to claim 1, wherein when the top of the existing structure is excavated for discharging soil, firstly, the pavement structure above the existing structure is mechanically broken, and then, the covering soil in the second set range on the two sides above the existing structure is manually cleaned to realize the slope discharging and the soil discharging.
5. The construction method for symmetric open cut extension of the side direction of the existing underground space according to claim 4, wherein when the thickness of the covering soil at the top of the existing structure is more than 2m, slope protection treatment is carried out on the covering soil which is not cleaned at the top of the existing structure.
6. The method for symmetric open cut extension construction of the existing underground space according to claim 1, wherein when the foundation pits on two sides of the existing structure are excavated synchronously and symmetrically, the excavation depth of the foundation pits on two sides is monitored in real time, so that the bottom surfaces of the foundation pits on two sides are relatively higher than Cheng Chaxiao m.
7. The method for symmetrically extending the lateral open cut of the existing underground space according to claim 1, wherein before the extending structure is poured, a grounding grid and a cushion layer are constructed on the bottom surface of the foundation pit, then the extending structure is poured, and a connection space is reserved between the extending structure and the existing structure during construction.
8. The construction method for open cut symmetrical extension of existing underground space according to claim 7, wherein after the construction of the top plate of the extension structure is completed, temporary section steel supports are provided between the top plate and the bottom plate of the extension structure where the construction is completed.
9. The construction method for symmetrical open cut extension of an existing underground space according to claim 1, wherein shear-resistant chemical anchors are constructed at the connection positions of the existing structures before the upper joist and the lower joist are cast, and the shear-resistant chemical anchors are arranged between the upper joist, the lower joist and the existing structures after the casting of the upper joist and the lower joist is completed.
10. The construction method for open cut symmetrical extension of the existing underground space according to claim 9, wherein the upper joist is of a C-shaped structure, and the top plate end of the existing structure is embedded into the upper joist end.
11. The construction method for open cut symmetrical extension of existing underground space according to claim 9, wherein temporary steel supports are arranged between the top plate and the bottom plate of the extension structure in the area between two newly built columns after construction of the two adjacent newly built columns is completed.
12. The construction method for symmetrical open cut extension of the existing underground space according to claim 1, wherein grouting pipes are reserved in the upper joist and the lower joist.
13. The construction method for symmetric open cut extension of the lateral direction of the existing underground space according to claim 1, wherein the concrete steps of the waterproof construction at the connection position are as follows:
coating cold base oil or moisture barrier agent on the top surface of the connection position of the existing structure and the extension structure;
Then coating a polyurethane waterproof paint layer;
then a PE film is paved on the surface of the polyurethane waterproof coating layer;
Then a PVC root penetration resistant layer is paved on the surface of the PE film;
And finally paving a fine stone concrete protective layer.
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| CN116201177A (en) * | 2023-03-14 | 2023-06-02 | 中铁第一勘察设计院集团有限公司 | Novel interface for underground engineering reconstruction and expansion based on permanent-temporary combination and construction method thereof |
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| CN204491624U (en) * | 2014-12-22 | 2015-07-22 | 上海建工集团股份有限公司 | The synchronous excavation supporting system of the asymmetric deep big foundation pit in soft clay area |
| CN110616740A (en) * | 2019-09-16 | 2019-12-27 | 北京市市政四建设工程有限责任公司 | Structure for expanding subway section in subway mine method construction interval and construction method thereof |
| CN110821503B (en) * | 2019-11-27 | 2021-10-15 | 中铁九局集团第四工程有限公司 | Construction method for main body of ultra-deep shield section air shaft after tunnel advance |
| CN115182354A (en) * | 2022-08-19 | 2022-10-14 | 中国建筑第八工程局有限公司 | Construction method for foundation pit groups on two sides of near-operation subway |
| CN115821985A (en) * | 2022-12-26 | 2023-03-21 | 北京住总集团有限责任公司 | Integrated construction method for auxiliary structure of subway open cut station |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN108842817A (en) * | 2018-07-18 | 2018-11-20 | 中铁贵州工程有限公司 | A kind of subway station overlays waterproof roll structure and its construction technology |
| CN113356219A (en) * | 2021-06-24 | 2021-09-07 | 天津市地质工程勘察院 | Synchronous excavation construction method for foundation pits at different depths on two sides of operation subway |
| CN116201177A (en) * | 2023-03-14 | 2023-06-02 | 中铁第一勘察设计院集团有限公司 | Novel interface for underground engineering reconstruction and expansion based on permanent-temporary combination and construction method thereof |
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