CN113653105A - Anti-floating system of existing subway structure and construction method thereof - Google Patents
Anti-floating system of existing subway structure and construction method thereof Download PDFInfo
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- CN113653105A CN113653105A CN202110961766.6A CN202110961766A CN113653105A CN 113653105 A CN113653105 A CN 113653105A CN 202110961766 A CN202110961766 A CN 202110961766A CN 113653105 A CN113653105 A CN 113653105A
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- area
- floating
- uplift
- box culvert
- bottom plate
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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
- E02D31/10—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 soil pressure or hydraulic pressure
- E02D31/12—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 soil pressure or hydraulic pressure against upward hydraulic pressure
Abstract
The invention relates to an anti-floating system of an existing subway structure and a construction method thereof, belonging to the technical field of rail transit. Through the anti-floating system that the construction stage gradually formed, with the box culvert bottom plate as anti-floating plate concurrently, the buoyancy that receives the subway structure is offset through the dead weight of box culvert bottom plate and resistance to plucking stake side frictional resistance, has innovatively solved because the not enough problem of anti-floating bearing capacity of existing subway structure that newly-built box culvert construction excavation caused.
Description
Technical Field
The invention belongs to the technical field of rail transit, and particularly relates to an anti-floating system of an existing subway structure and a construction method thereof.
Background
With the development of the urban scale to the super-huge and super-large cities, the urban space is continuously excavated and utilized, and the construction land contradiction is intensified. Newly-built structure can produce certain influence to existing underground structure on the vertical space, and especially not dark to existing subway structure earthing, other structures are newly-built in its top excavation, will arouse existing subway structure's come-up deformation and internal force change problem, for example: newly-built municipal box culvert structure in not dark existing subway structure top of earthing, when newly-built box culvert structural construction, along with the excavation of foundation ditch, arouse the interval come-up of the shield of the existing subway structure in below to warp, newly-built box culvert bottom plate is not enough with the vertical space in subway structure top simultaneously, is difficult to set up conventional anti system of floating, causes a series of problems such as subway structure security reduction during newly-built box culvert construction from this, subway operation risk increases, municipal box culvert construction degree of difficulty increase.
Disclosure of Invention
Aiming at the technical problems in the prior art, the invention provides an anti-floating system of an existing subway structure and a construction method thereof.
The embodiment of the invention provides an anti-floating system of an existing subway structure, which comprises a soil body reinforcing area arranged on the outer side of the wall surface of a subway tunnel, wherein N anti-floating piles are vertically arranged in the soil body reinforcing area, the tops of the N anti-floating piles are connected through anti-floating beams to form a grid structure, a box culvert bottom plate is arranged at the top of the soil body reinforcing area, and the anti-floating beams are embedded in the box culvert bottom plate.
Further, the box culvert bottom plate and the grid structure are of an integral structure.
And further, the steel bars of the horizontal floating resisting beam are fixedly connected with the steel bars in the uplift pile.
Further, the soil body reinforcing area is formed by reinforcing the triaxial mixing piles.
Furthermore, the uplift pile is circular in cross section, and the floating beam is rectangular in cross section.
The embodiment of the invention provides a construction method of an existing subway structure anti-floating system based on any one of the above, which comprises the following steps:
reinforcing soil outside the wall surface of the subway tunnel to form a soil reinforcing area; constructing uplift piles in the soil body reinforcing area;
symmetrically dividing earth covering on the top of a subway tunnel earth reinforcement area into a first area and a second area; then the first area and the second area are respectively divided into a plurality of same area segments,
respectively and simultaneously excavating the first area and the second area towards the direction close to the symmetry line, and gradually exposing the breaking section at the top of the uplift pile in the soil body reinforcing area;
and when one area section is dug, exposing the top of the uplift pile in the dug area section, breaking the concrete on the pile top, connecting the reinforcing steel bars in the uplift pile and the reinforcing steel bars in the uplift beam together, pouring a box culvert bottom plate in the area, realizing the fixed connection of the box culvert bottom plate, the uplift beam and the uplift pile, and finally sequentially digging the area sections in the first area and the second area to form an integral uplift system.
Further, the soil body reinforcing area is reinforced through the triaxial mixing pile.
Further, before the box culvert bottom plate is poured, a plain concrete cushion layer is applied to the bottom in advance.
And furthermore, chiseling exposed broken sections of the uplift piles to expose the uplift pile steel bars inside the uplift piles, welding or binding the uplift pile steel bars inside the uplift beams, and fixedly connecting the uplift pile steel bars with the uplift beam steel bars to realize the connection of the uplift piles and the uplift beams.
Furthermore, the whole anti system of floating of existing subway structure forms, and after the box culvert major structure construction was accomplished, the box culvert both sides adopted the rubble soil to carry out the layering compaction backfill.
The invention has the following beneficial effects:
according to the existing subway anti-floating system provided by the invention, when an existing subway structure is subjected to larger buoyancy, the subway structure can transmit the buoyancy to the box culvert bottom plate at the top through the peripheral soil body reinforcing area, the box culvert bottom plate uniformly transmits the buoyancy to the anti-floating piles through the anti-floating beams, the anti-floating beams can prevent the stress at the connecting part of the top of the anti-floating piles and the box culvert bottom plate from being overlarge, so that the buoyancy applied to the subway structure is counteracted together through the self weight of the box culvert bottom plate and the friction between the outer wall surface of the anti-floating piles and the soil body reinforcing area, and other structures can be newly excavated above the existing subway structure under the condition of not deep soil covering of the existing subway structure, so that the problems of floating deformation and internal force change of the existing subway structure are solved.
The construction method of the existing subway anti-floating system can effectively solve the problem of insufficient anti-floating capacity during earth-covering excavation of the top of the existing subway structure; the soil body around the subway structure is reinforced, so that the force transmission efficiency and the stress uniformity of the anti-floating system are improved; the top soil of the subway tunnel is symmetrically excavated in blocks, and the box culvert bottom plate is built in blocks, so that the conversion from a local anti-floating system to an overall anti-floating system is realized, the risk resistance of the existing subway structure is enhanced, and the normal safe operation of the existing subway during the construction of a newly built box culvert is guaranteed.
Drawings
FIG. 1 is a schematic elevation view of an existing subway structure anti-floating system combined with a newly-built municipal bridge and culvert, provided by an embodiment of the present invention;
FIG. 2 is a schematic plan view of an existing subway structure anti-floating system combined with a newly-built municipal bridge and culvert, provided by the embodiment of the invention
FIG. 3 is a schematic diagram of a construction process according to an embodiment of the present invention
In the figure, 1, an anti-floating plate, 2, an anti-floating beam, 3, an anti-pulling pile, 4, a soil body reinforcing area, 5 and an existing subway structure
Detailed Description
As shown in fig. 1 and 2, an embodiment of the present invention provides an anti-floating system for an existing subway structure, where the system includes a soil reinforcing area 4 disposed around a wall surface of an existing subway structure 5, a plurality of anti-floating piles 3 are disposed around the soil reinforcing area 4, the anti-floating piles 3 are vertically inserted into the soil reinforcing area 4, and tops of the anti-floating piles 3 are connected together through anti-floating beams 2 to form a grid structure.
The top of subway tunnel is equipped with box culvert bottom plate 1, anti-floating beam 2 is embedded in box culvert bottom plate 1, is in the same place or with box culvert bottom plate 1 structure as an organic whole with box culvert bottom plate 1 is fixed.
Therefore, the existing subway anti-floating system provided by the embodiment can generate certain floating deformation when a box culvert is newly built at the top of the existing subway, at the moment, the existing subway structure can transmit buoyancy to the box culvert bottom plate 1 at the top through the surrounding soil body reinforcing area 4, the box culvert bottom plate 1 transmits the buoyancy to the anti-floating beam 2 and the uplift pile 3, so that the buoyancy received by the subway structure can be offset together through the dead weight of the box culvert bottom plate 1 and the friction between the outer wall surface of the uplift pile 3 and the soil body reinforcing area, so that the earth of the existing subway structure is not deep, other structures are newly built above the existing subway structure, and the problems of floating deformation and internal force change of the existing subway structure are solved.
Preferably, the box culvert bottom plate 1 in the implementation is a reinforced concrete member, and is cast in situ, so that the municipal box culvert bottom plate is also used as an anti-floating plate of an anti-floating system of an existing subway structure, and the thickness of the box culvert bottom plate is determined by structural calculation.
In order to increase the gravity of the box culvert bottom plate 1, the top surface of the box culvert bottom plate 1 can be compacted with soil in the construction process, so that the gravity of the box culvert bottom plate 1 can be increased, and a box culvert web and a box culvert top plate are poured after the construction of the box culvert bottom plate 1 is completed.
The section of the uplift pile 3 is circular, and because the uplift pile is stressed along the axial direction, a reinforced concrete axial stressed member is preferred.
The uplift pile 3 can calculate and determine the diameter, the length and the arrangement distance of the uplift pile according to parameters such as rock-soil mechanical parameters, water level height and side friction coefficient, and meets the anti-floating design requirement.
Further, the anti-floating beam 2 has a rectangular cross section, and is preferably a reinforced concrete flexural member because it mainly bears a bending moment. Because the anti-floating beam 2 connects the box culvert bottom plate 1 and the anti-floating pile 3 to form an anti-floating system which is a main force transmission component, the construction size of the anti-floating system needs to be determined by calculation.
The top of uplift pile 3 in this embodiment is equipped with the region that one section can be abolished, can be called the abolishing section, and when linking together the top of uplift beam 2 and uplift pile 3, can spill inside reinforcing bar for the chisel opening with the top of uplift pile 3, then link together the reinforcing bar welding at the inside reinforcing bar of uplift beam 2 and the reinforcing bar at uplift pile 3 top or through other modes, just so realized the fixed connection of uplift beam 2 and uplift pile 3.
In this embodiment the soil body reinforcing area 4 can adopt the triaxial stirring stake to consolidate the soil body, makes the soil body formation rigid shell around the subway structure, can guarantee like this that the buoyancy that existing subway structure received can evenly transmit for anti floating system, ensures going on smoothly of earthing symmetry piecemeal layering excavation simultaneously, simultaneously passes through soil body reinforcing area 4 can be convenient for transmit the buoyancy that the subway received for the box culvert bottom plate 1 at top.
The construction process of the existing subway structure anti-floating system provided by the embodiment comprises the following steps:
the method comprises the following steps: reinforcing soil outside the wall surface of the subway tunnel to form a soil reinforcing area 4; constructing uplift piles in the soil body reinforcing area 4;
the concrete process is to level the place at the top of the subway tunnel, then excavate the guide slot to the soil body reinforcement area 4, carry out the triaxial stirring stake to the soil body in the subway tunnel outside through the triaxial mixer for soil body reinforcement area 4 is formed to soil body around, just so makes the subway structure bear great buoyancy when, can pass through soil body reinforcement area 4 with buoyancy and transmit.
The three-shaft stirrer is dug along with the construction of the guide groove in the construction process, so that slurry is prevented from overflowing; meanwhile, the triaxial mixing pile is constructed according to the designed pile length, and the corresponding construction process requirements are met.
The diameter, the length and the arrangement distance of the uplift piles 3 are determined according to parameters such as rock-soil mechanical parameters, water level height and side friction resistance coefficient, and meanwhile, a breaking section is reserved at the top of the uplift pile 3 and is convenient to be connected with the anti-floating beam 2.
Step two: symmetrically dividing earth covering on the top of a subway tunnel earth reinforcement area into a first area and a second area; respectively dividing the first area and the second area into a plurality of same area segments;
referring to fig. 3, assuming that excavation is performed on the top of the subway tunnel along a direction perpendicular to the extending direction of the subway tunnel, the area on the top of the subway tunnel is divided into a left area and a right area, wherein the left area is divided into (i) -region ends, and the right area is divided into (i) -region sections, so that the left area and the right area can be simultaneously and sectionally excavated.
Step three: respectively and simultaneously excavating the first area and the second area towards the direction close to the symmetry line, and gradually exposing the breaking section at the top of the uplift pile in the soil body reinforcing area;
referring to fig. 3, in the third step, the left area and the right area are respectively excavated towards the middle area simultaneously, or are excavated along the direction of the symmetry line close to the left area and the right area, specifically, the first section in the left area and the right area is excavated downwards simultaneously, and then the second section, the third section and the fourth section are excavated sequentially.
In the third step, when the simultaneous downward excavation is carried out in the two side areas, the strict control of the soil unloading thickness of each layer is required.
In the third step, when the actual elevation distance of each area section excavation is 0.5m from the design elevation, the mechanical excavation is changed into manual excavation, the excavation is carried out until the design elevation is reached, excessive excavation is not required, and meanwhile, in the excavation process, broken sections at the tops of uplift piles in the first-fourth area sections in the left area and the right area need to be exposed.
Step four: when one area section is dug, breaking a broken section exposed out of the top of the uplift pile in the dug area section, connecting the broken section with the uplift beam, pouring a box culvert bottom plate in the area, realizing the fixed connection of the box culvert bottom plate, the uplift beam and the uplift pile, and finally sequentially digging the area sections in the first area and the second area to form an integral uplift system;
specifically, referring to fig. 3, in the fourth step, when the elevation of the box culvert bottom plate which can be poured is dug in the first area section of the left area and the right area, stopping, and then constructing a C15 plain concrete cushion layer with the thickness of 10cm at the bottom of the first area section to be used as a box culvert bottom mold; exposing the broken sections of the uplift piles in the first area sections in the left and right side areas, connecting the uplift piles with the horizontal uplift beams, and meanwhile, pouring longitudinal uplift beams at the top of each uplift pile in the first area to prepare for being connected with the uplift piles in the second area; after the tops of the uplift piles in the first area are connected through the anti-floating beams, the box culvert bottom plate is poured in situ, so that the box culvert bottom plate in the first area, the tops of the uplift piles in the first area and the anti-floating beams are poured into a whole, and a local anti-floating system is formed.
According to the operation flow, the anti-floating beams are excavated and poured in the areas II, III and IV in the left area and the right area respectively, box culvert bottom plates are poured in sections, and finally an integral anti-floating system is formed at the top of the subway tunnel, so that the conversion from a local anti-floating system to the integral anti-floating system is realized, and the operation flow is shown in figure 2.
In the fourth step, the anti-floating beam in the embodiment needs to be cast in place, and meanwhile, a post-cast strip needs to be reserved when the box culvert bottom plate is cast.
It should be noted that, in the fourth step, the concrete connection process of the anti-floating beam 2 and the anti-floating pile 3 is to chisel the broken section at the top of the anti-floating pile 3 in advance, so as to facilitate the leakage of the anti-floating pile steel bars in the anti-floating pile, meanwhile, some anti-floating beam steel bars are penetrated in the anti-floating beam 2, and the anti-floating pile steel bars and the anti-floating beam steel bars are welded and fixed or fixed together in other manners, so that the fixation of the anti-floating pile and the anti-floating beam is realized.
Therefore, the construction method adopting the anti-floating system provided by the embodiment can effectively solve the problem of insufficient anti-floating capacity during the top earthing and excavation of the existing subway structure; the soil body around the subway structure is reinforced, so that the force transmission efficiency and the stress uniformity of the anti-floating system are improved; the top soil of the subway tunnel is symmetrically excavated in blocks, and the box culvert bottom plate is built in blocks, so that the conversion from a local anti-floating system to an overall anti-floating system is realized, the risk resistance of the existing subway structure is enhanced, and the normal safe operation of the existing subway during the construction of a newly built box culvert is guaranteed.
Finally, the above embodiments are only intended to illustrate the technical solutions of the present invention and not to limit the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions, and all of them should be covered by the claims of the present invention.
Although the embodiments of the present invention have been described with reference to the accompanying drawings, it is not intended to limit the scope of the present invention, and it should be understood by those skilled in the art that various modifications and variations can be made without inventive efforts by those skilled in the art based on the technical solution of the present invention.
Claims (10)
1. The utility model provides an existing subway structure anti-floating system, its characterized in that, is including setting up the soil body reinforcing area in the subway tunnel wall outside be equipped with the vertical anti-floating pile that sets up of N in the soil body reinforcing area, wherein N is the integer, and N anti-floating pile is connected with anti-floating beam and forms the grid structure the top in soil body reinforcing area is equipped with the box culvert bottom plate, anti-floating beam is embedded in the box culvert bottom plate.
2. An existing subway structure anti-floating system as claimed in claim 1, wherein the box culvert bottom plate and the grid structure are an integral structure.
3. An existing subway structure anti-floating system as claimed in claim 1, wherein the reinforcing steel bars in the anti-floating beam and the reinforcing steel bars in the uplift pile are fixedly connected.
4. An existing metro structure anti-floating system as claimed in claim 1, wherein the soil consolidation area is formed by three-axis mixing piles.
5. An existing subway structure anti-floating system as claimed in claim 1, wherein said anti-floating piles are circular in cross section, and said anti-floating beams are rectangular in cross section.
6. The construction method of the existing subway structure anti-floating system based on any one of claims 1-5,
reinforcing soil outside the wall surface of the subway tunnel to form a soil reinforcing area; constructing uplift piles in the soil body reinforcing area;
symmetrically dividing earth covering on the top of a subway tunnel earth reinforcement area into a first area and a second area; then the first area and the second area are respectively divided into a plurality of same area segments,
respectively and simultaneously excavating the first area and the second area towards the direction close to the symmetry line, and gradually exposing the breaking section at the top of the uplift pile in the soil body reinforcing area;
and when one area section is dug, connecting the tops of the uplift piles in the dug area section together through the uplift beams, pouring a box culvert bottom plate in the dug area section to realize the fixed connection of the box culvert bottom plate, the uplift beams and the uplift piles, and finally sequentially digging the area sections in the first area and the second area to form an integral uplift system.
7. The method of claim 6, wherein the soil consolidation area is consolidated by a triaxial mixing pile.
8. The construction method according to claim 6, wherein a plain concrete cushion is applied to the bottom in advance before the box culvert bottom plate is poured.
9. The construction method according to claim 6, wherein the exposed broken section of the uplift pile is broken to expose the inner reinforcing steel bars of the uplift pile, and then the reinforcing steel bars of the uplift pile are welded or bound in the inner part of the anti-floating beam, so that the uplift pile and the anti-floating beam are fixedly connected to realize the connection of the uplift pile and the anti-floating beam.
10. The construction method according to claim 6, wherein after the construction of the box culvert main body structure is completed, the two sides of the box culvert are backfilled by adopting gravel soil through layered compaction.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110961766.6A CN113653105A (en) | 2021-08-20 | 2021-08-20 | Anti-floating system of existing subway structure and construction method thereof |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110961766.6A CN113653105A (en) | 2021-08-20 | 2021-08-20 | Anti-floating system of existing subway structure and construction method thereof |
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| CN113653105A true CN113653105A (en) | 2021-11-16 |
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| CN202110961766.6A Withdrawn CN113653105A (en) | 2021-08-20 | 2021-08-20 | Anti-floating system of existing subway structure and construction method thereof |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114086562A (en) * | 2021-11-27 | 2022-02-25 | 哈尔滨工业大学 | Foundation pit construction method for advanced reinforcement right above subway tunnel operated in high and cold region |
| CN114457850A (en) * | 2022-03-11 | 2022-05-10 | 浙江交工集团股份有限公司 | Construction method of anti-floating system for crossing existing subway intersection section on open trench tunnel |
| CN115126008A (en) * | 2022-06-17 | 2022-09-30 | 广州地铁设计研究院股份有限公司 | Anti-floating device for post-construction station and construction method thereof |
-
2021
- 2021-08-20 CN CN202110961766.6A patent/CN113653105A/en not_active Withdrawn
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114086562A (en) * | 2021-11-27 | 2022-02-25 | 哈尔滨工业大学 | Foundation pit construction method for advanced reinforcement right above subway tunnel operated in high and cold region |
| CN114457850A (en) * | 2022-03-11 | 2022-05-10 | 浙江交工集团股份有限公司 | Construction method of anti-floating system for crossing existing subway intersection section on open trench tunnel |
| CN115126008A (en) * | 2022-06-17 | 2022-09-30 | 广州地铁设计研究院股份有限公司 | Anti-floating device for post-construction station and construction method thereof |
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Application publication date: 20211116 |
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