A construction method for the main structure of an assembled subway station based on the cover-excavation reverse construction method

Abstract

The present invention discloses a method for constructing the main structure of an assembled subway station based on a cover-and-excavation reverse construction method, comprising: underground continuous wall construction, excavation of overburden and pile drilling, precast pile construction, hoisting of precast top beams, hoisting of precast top slabs, post-casting of top beam-slab-column joints, post-casting of top slab-side wall joints, backfilling of overburden, excavation of the first underground floor, hoisting of precast center beams, hoisting of precast center slabs, post-casting of center beam-slab-column joints, post-casting of center slab-side wall joints, excavation of the second underground floor, pouring of the bottom slab cushion layer, placing and suspending the precast bottom beam, tying of the bottom slab reinforcement, post-casting of the bottom slab, and post-casting of the bottom beam-column joints. The bottom slab of the present invention is cast in place, and the top beams, top slabs, longitudinal beams, and floor slabs are all precast. The underground continuous wall and precast piles serve as temporary enclosure members and also as permanent vertical support members. Only a simple formwork needs to be set up, and after the top slab is installed, the overburden is backfilled to restore the road surface, which greatly reduces the construction period and minimizes the impact of the construction on urban traffic and the environment.

Description

Technical Field

[0001] The present invention relates to the technical field of subway station construction, and in particular to a method for constructing the main structure of an assembled subway station based on a cover-and-cut reverse construction method. Background Art

[0002] With my country's rapid socioeconomic development and accelerating urbanization, urban underground rail transit has become the only solution to current traffic congestion. The cut-and-cover top-down construction technology for subway stations not only minimizes the impact on surface traffic but also significantly reduces the environmental impact of noise and dust. Furthermore, the overall structural system of these stations exhibits high lateral stiffness, effectively controlling foundation pit deformation and surrounding building and ground subsidence during excavation. Consequently, this technology has proven to be highly valuable and has been widely adopted.

[0003] Traditional cut-and-cover subway stations often use a traditional cast-in-place construction process. This process is prone to dust and noise pollution, formwork material consumption, large construction site staff, high labor intensity, and difficult project quality control. Therefore, a construction method for prefabricated subway stations based on the cut-and-cover method is clearly necessary and urgent for the safe and efficient development of urban underground space resources. Summary of the Invention

[0004] Aiming at the problems of long construction period, large consumption of moulds and high labor intensity of current subway stations constructed by cover-excavation-top-down construction method, the present invention proposes a construction method for the main structure of an assembled subway station based on cover-excavation-top-down construction method.

[0005] The present invention adopts the following technical solution: a method for constructing the main structure of an assembled subway station based on the cover-excavation reverse construction method, characterized by comprising the following steps:

[0006] S1. Conduct underground diaphragm wall construction: trench the underground diaphragm wall within the subway station construction area, tie the underground diaphragm wall reinforcement cage, embed several sealed rectangular steel pipes in the reinforcement cage from bottom to top, place the underground diaphragm wall reinforcement cage, and pour the underground diaphragm wall concrete;

[0007] S2. Excavate from the original ground level down to the lower surface of the top plate, level the site and locate the pile holes, drill holes to the lower surface of the bottom plate, and drive several intermediate pile foundations. Hang precast piles above each intermediate pile foundation to the specified elevation and hammer the piles.

[0008] S3. Hoist the top beam onto the steel bracket of the precast pile top beam, connect the lap steel bars at the end of the top beam to the reserved top beam tower steel bars of the precast pile, and weld the main bars;

[0009] S4. After the top beam is connected, remove the embedded sealed rectangular steel pipe cover, weld the top beam steel brackets, and hoist the top plate to the top beam and the upper surface of the top beam steel brackets. Overlap the top plate's extended steel bars with the reserved U-shaped bars in the underground continuous wall and the top beam's U-shaped lap bars. Set up a simple formwork, and then cast the top beam-slab-column joints and the top plate-side wall joints.

[0010] S5. Backfill the upper soil, reserve several top plate areas as excavation openings, excavate downward to the bottom of the subway station middle plate to a preset height, remove the pre-buried sealed rectangular steel pipe cover, and weld the middle beam steel brackets;

[0011] S6. Hoist the center beam onto the steel brackets of the precast pile center beam. Lap the lap steel bars at the ends of the center beam with the steel bars reserved for the center beam towers of the precast piles, and weld the main bars.

[0012] S7. Hoist the center plate to the upper surface of the center beam and the center beam steel corbels. Overlap the extended reinforcement of the center plate with the reserved U-shaped reinforcement of the underground continuous wall and the U-shaped lap reinforcement of the center beam. Set up a simple formwork, and post-cast the center beam-slab-column joints and the center plate-side wall joints. Reserve several areas of the center plate for excavation openings.

[0013] S8. Excavate downward to the bottom plate casting surface, make a bottom plate concrete cushion on the soil surface of the bottom plate casting surface, tie the bottom plate steel bars, remove the embedded sealed rectangular steel pipe cover, and install the bottom beam steel corbel;

[0014] S9. The bottom beam is in place and suspended. The lap reinforcement at the end of the bottom beam is overlapped with the reinforcement reserved for the bottom beam tower of the precast pile, and the main reinforcement is welded;

[0015] S10, pour the base plate in one go. No formwork is required for pouring the base plate to the designed elevation, and the base plate concrete is cured.

[0016] S11. Set up simple formwork, cast the core area of ​​the bottom plate beam-column joint, and complete the construction of the main structure of the station.

[0017] Preferably, three sealed rectangular steel pipes are arranged at intervals from bottom to top, and each sealed rectangular steel pipe includes: a steel pipe haunch, a sealing ring, and a U-shaped floor slab lap reinforcement; bolt holes are reserved at the steel pipe haunch for installing the corbel;

[0018] The sealed rectangular steel tube is sealed at both ends, and a reinforced steel plate is placed inside the tube cavity to connect it to the concrete. A sealing ring is placed on the reinforced steel plate to prevent grout leakage. The U-shaped slab lap reinforcement passes through the holes in the reinforced steel plate, pressing against the sealing ring before being welded to the back. A cover plate is placed on the side closest to the plate, and a sealing ring is placed on the side away from the plate to ensure that no soil or concrete enters the rectangular steel tube cavity.

[0019] Preferably, the prefabricated pile body is cylindrical and comprises, from bottom to top, pile tip, bottom beam tower connection steel bar, bottom beam steel bracket, middle beam steel bracket, middle beam tower connection steel bar, top beam steel bracket, and top beam tower connection steel bar;

[0020] The top beam steel corbel, middle beam steel corbel and bottom beam steel corbel are used to fix the top beam, middle beam and bottom beam respectively. The top beam tower joint steel bars, middle beam tower joint steel bars and bottom beam tower joint steel bars are used to overlap with the reserved steel bars of the top beam, middle beam and bottom beam respectively.

[0021] Preferably, a grouting sleeve is also embedded in the top of the prefabricated pile column for connection with the top beam.

[0022] Preferably, the bottom plate is cast in situ, and the top beam, top plate, middle beam and middle plate are all prefabricated.

[0023] Compared with the prior art, the present invention adopts the above technical solution and has the following technical effects:

[0024] The present invention discloses a method for constructing the main structure of an assembled subway station based on the cover-excavation top-down method, which can reduce defects such as dust and noise pollution caused by construction, consumption of formwork materials, large number of people on the construction site, high labor intensity, and difficulty in project quality control. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is the construction flow chart of the prefabricated subway station constructed by the cover-excavation reverse construction method of the present invention

[0026] Figure 2 This is the state of the main structure of the assembled subway station constructed by the cover-excavation reverse construction method of the present invention Figure 1 ;

[0027] Figure 3 This is the state of the main structure of the assembled subway station constructed by the cover-excavation reverse construction method of the present invention Figure 2 ;

[0028] Figure 4 This is the state of the main structure of the assembled subway station constructed by the cover-excavation reverse construction method of the present invention Figure 3 ;

[0029] Figure 5 This is the state of the main structure of the assembled subway station constructed by the cover-excavation reverse construction method of the present invention Figure 4 ;

[0030] Figure 6 This is the state of the main structure of the assembled subway station constructed by the cover-excavation reverse construction method of the present invention Figure 5 ;

[0031] Figure 7 This is the state of the main structure of the assembled subway station constructed by the cover-excavation reverse construction method of the present invention Figure 6 ;

[0032] Figure 8 This is a schematic diagram of the sealed rectangular steel pipe structure of the present invention;

[0033] Figure 9 Schematic diagram of the prefabricated pile structure of the present invention;

[0034] Explanation of the accompanying reference numerals: 1. underground continuous wall; 2. sealed rectangular steel pipe; 3. precast pile; 4. intermediate pile foundation; 5. top beam steel corbel; 6. top beam; 7. top plate; 8. overburden; 9. top beam-plate-column node; 10. top plate-side wall node; 11. middle beam steel corbel; 12. middle beam; 13. middle plate; 14. middle beam-plate-column node; 15. middle plate-side wall node; 16. bottom beam steel corbel; 17. bottom beam; 18. bottom plate. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions of the application are further elaborated in detail below with reference to the accompanying drawings. The described embodiments are only a part of the embodiments involved in the present invention. All non-innovative embodiments of other researchers in this field on this embodiment fall within the scope of protection of the present invention. At the same time, the step numbers in the embodiments of the present invention are only set for the convenience of explanation and description, and the order between the steps is not limited in any way. The execution order of each step in the embodiment can be adaptively adjusted according to the understanding of those skilled in the art.

[0036] In one embodiment of the present invention, a method for constructing the main structure of an assembled subway station based on the cover-excavation reverse construction method is provided. Figure 1 As shown, the following steps are included:

[0037] Step 1: Use the cover-excavation reverse construction method to construct the underground continuous wall 1. Carry out the underground continuous wall trenching in the subway station construction area, tie the underground continuous wall reinforcement cage, and embed three sealed rectangular steel pipes 2 in the reinforcement cage and seal the rectangular steel pipes. Place the underground continuous wall reinforcement cage and pour the underground continuous wall concrete. Figure 2 shown.

[0038] In this embodiment, the underground continuous wall is a side wall; the sealed rectangular steel pipe, such as Figure 8 As shown, there are three sealed rectangular steel pipes 2 spaced apart from each other from bottom to top, and each sealed rectangular steel pipe 2 includes: a steel pipe haunch, a sealing ring, and a U-shaped floor slab lap reinforcement; bolt holes are reserved at the steel pipe haunch for installing corbels.

[0039] Preferably, the sealed rectangular steel tube 2 is sealed at both ends, and a steel plate reinforced with steel bars is placed inside the rectangular steel tube cavity to connect it to the concrete. The steel plate reinforced with steel bars is sealed with a sealing ring to prevent leakage. The U-shaped floor slab lap reinforcement passes through the holes in the steel plate reinforced with steel bars, presses against the sealing ring, and is then welded to the back. A cover plate is provided on the side of the sealed rectangular steel tube 2 close to the plate, and a sealing ring is provided on the side away from the plate to ensure that no soil or concrete enters the inner cavity of the rectangular steel tube, which would affect the subsequent welding of the plate reinforcement and the reserved U-shaped reinforcement.

[0040] Step 2: Dig down from the original ground level to the lower surface of the top plate 7, level the site and locate the pile holes, drill holes to the lower surface of the bottom plate 18, drive the intermediate pile foundation 4 in the subway station construction area, hang the prefabricated piles 3 to the specified elevation, and hammer the piles. Figure 3 shown.

[0041] Preferably, in this embodiment, Figure 9 As shown, the main body of the precast pile is cylindrical and includes, from bottom to top: pile tip, bottom beam tower connection steel bar, bottom beam steel bracket, middle beam steel bracket, middle beam tower connection steel bar, top beam steel bracket, top beam tower connection steel bar;

[0042] The top beam steel corbel, middle beam steel corbel and bottom beam steel corbel are used to fix the top beam, middle beam and bottom beam respectively. The top beam tower joint steel bars, middle beam tower joint steel bars and bottom beam tower joint steel bars are used to overlap with the reserved steel bars of the top beam, middle beam and bottom beam respectively.

[0043] A grouting sleeve is also embedded in the top of the prefabricated pile column for connection with the top beam.

[0044] Step 3: After the prefabricated pile construction is completed, the prefabricated top beam 6 is hoisted onto the top beam steel bracket 5 of the prefabricated pile body. The top beam end lap steel bars are overlapped with the top beam tower steel bars reserved in the prefabricated pile body and the main bars are welded. The sealed rectangular steel pipe cover is removed and the top beam steel bracket 5 is welded. Figure 4 shown.

[0045] Step 4: Hoist the prefabricated top plate 7 to the upper surface of the top beam 6 and the top beam steel corbel 5, overlap the protruding steel bars of the top plate 7 with the reserved U-shaped bars of the underground continuous wall and the U-shaped lap bars of the top beam, set up a simple formwork, and then cast the top beam-slab-column node 9 and the top plate-side wall node 10.

[0046] Step 5: Backfill the upper covering soil 8, reserve some top plate areas as the excavation opening, and excavate the soil downward to the height of 1.6m below the bottom of the subway station middle plate 13; Figure 5 As shown; remove the embedded sealed rectangular steel pipe 2 cover and weld the middle beam steel corbel 11.

[0047] Step 6: Hang the center beam 12 onto the center beam steel bracket 11 of the precast pile 3, overlap the beam end lap steel bars with the center beam tower steel bars reserved on the precast pile body and weld the main bars.

[0048] Step 7: Hang the prefabricated middle plate 13 to the upper surface of the middle beam 12 and the middle beam steel corbel 11, overlap the extended steel bars of the middle plate 13 with the reserved U-shaped bars of the underground continuous wall and the U-shaped lap bars of the middle beam, set up a simple formwork, and cast the middle beam column node 14 and the middle plate-side wall node 15. Figure 6 shown.

[0049] Step 8: Excavate downwards to the bottom plate casting surface, construct the bottom plate concrete cushion layer on the soil surface of the bottom plate casting surface, tie the bottom plate steel bars, remove the pre-buried sealed rectangular steel pipe 2 cover plate, and install the bottom beam steel bracket 16.

[0050] Step 9: Hoist the prefabricated bottom beam 17, overlap the beam end lap steel bars with the bottom beam tower connection steel bars reserved for the prefabricated pile body, and weld the main bars.

[0051] Step 10: Cast the base plate 18 in one go. The base plate does not need to be cast in formwork. Cast the base plate to the designed elevation and perform base plate concrete curing. Figure 7 shown.

[0052] Step 11: Set up simple formwork, cast the core area of ​​the bottom plate 18 beam-column nodes, and complete the construction of the main structure of the station.

[0053] The present invention is based on the construction method of the main structure of an assembled subway station using the cover-and-cut top-down method, which effectively solves the problems of long construction period, large mold consumption, and high labor intensity of the current subway stations using the cover-and-cut top-down method. At the same time, by increasing the prefabrication rate, the design greatly reduces the construction period and minimizes the impact of construction on urban traffic and the environment.

[0054] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for constructing the main structure of an assembled subway station based on the cover-excavation reverse construction method, characterized in that: The steps include: S1, constructing an underground continuous wall (1), forming a trench for the underground continuous wall (1) in the subway station construction area, tying up the underground continuous wall reinforcement cage, and pre-embedding a plurality of sealed rectangular steel pipes (2) in the reinforcement cage from bottom to top, placing the underground continuous wall reinforcement cage and pouring the underground continuous wall concrete; S2, excavating downward from the original ground elevation to the lower surface of the top plate (7), leveling the site and positioning the pile holes, drilling holes to the lower surface of the bottom plate (18), and laying a number of intermediate pile foundations (4). Above each intermediate pile foundation (4), hanging prefabricated piles (3) to a specified elevation, and hammering the piles; S3, hoisting the top beam (6) onto the top beam steel bracket (5) of the precast pile (3), overlapping the top beam (6) end with the top beam tower steel bar reserved for the precast pile (3), and welding the main reinforcement; S4. After the top beam (6) is connected, the cover plate of the embedded sealed rectangular steel pipe (2) is removed, the top beam steel bracket (5) is welded, the top plate (7) is hoisted to the top beam (6) and the upper surface of the top beam steel bracket (5), the top plate (7) is extended and connected with the U-shaped reinforcement reserved in the underground continuous wall (1) and the U-shaped lap reinforcement of the top beam (6), a simple formwork is set up, and the top beam plate column node (9) and the top plate-side wall node (10) are cast later; S5, backfill the upper covering soil (8), reserve several top plate areas as the excavation port, excavate the soil downward to the bottom of the subway station middle plate (13) to a preset height, remove the pre-buried sealed rectangular steel pipe (2) cover plate, and weld the middle beam steel bracket (11); S6, hoisting the middle beam (12) onto the middle beam steel bracket (11) of the precast pile (3), overlapping the end lap steel bars of the middle beam (12) with the reserved middle beam tower steel bars of the precast pile (3), and welding the main bars; S7, hoisting the middle plate (13) to the upper surface of the middle beam (12) and the middle beam steel corbel (11), overlapping the extended steel bars of the middle plate (13) with the reserved U-shaped bars of the underground continuous wall (1) and the U-shaped lap bars of the middle beam (12), setting up a simple formwork, post-casting the middle beam-slab-column joint (14), and post-casting the middle plate-side wall joint (15), and reserving several middle plate areas as excavation openings; S8, excavate downward to the casting surface of the bottom plate (18), make a bottom plate concrete cushion on the soil surface of the bottom plate casting surface, tie the bottom plate steel bars, remove the embedded sealed rectangular steel pipe cover, and install the bottom beam steel bracket (16); S9, the bottom beam (17) is in place and suspended, the end lap steel bars of the bottom beam (17) are overlapped with the reserved bottom beam tower steel bars of the prefabricated pile (3), and the main bars are welded; S10, performing one-time bottom plate (18) pouring, the bottom plate pouring does not require supporting formwork, pouring to the design elevation, and performing bottom plate (18) concrete curing; S11. Set up simple formwork and cast the core area of ​​the base plate (18) beam-column joint to complete the construction of the main structure of the station.

2. The method for constructing the main structure of an assembled subway station based on the cover-excavation top-down method according to claim 1 is characterized in that: The three sealed rectangular steel pipes (2) are arranged at intervals from bottom to top, and each sealed rectangular steel pipe comprises: a steel pipe haunch, a sealing ring, and a U-shaped floor slab lap reinforcement; bolt holes are reserved at the steel pipe haunch for installing corbels; The sealed rectangular steel pipe is sealed at both ends, and a steel reinforcement plate is built into the cavity of the rectangular steel pipe to connect with the concrete; the steel reinforcement plate is prevented from leaking by providing a sealing ring; the U-shaped floor lap reinforcement passes through the holes of the steel reinforcement plate to press the sealing ring and then is welded and fixed on the back.

3. The method for constructing the main structure of an assembled subway station based on the cover-excavation reverse construction method according to claim 2 is characterized in that: The sealed rectangular steel pipe (2) is provided with a cover plate on the side close to the plate and a sealing ring on the side away from the plate, so as to ensure that no soil or concrete enters the inner cavity of the rectangular steel pipe.

4. The method for constructing the main structure of an assembled subway station based on the cover-excavation reverse construction method according to claim 1 is characterized in that: The prefabricated pile body is cylindrical and comprises, from bottom to top, a pile tip, a bottom beam tower connecting steel bar, a bottom beam steel bracket (16), a middle beam steel bracket (11), a middle beam tower connecting steel bar, a top beam steel bracket (5), and a top beam tower connecting steel bar; The top beam steel bracket (5), the middle beam steel bracket (11) and the bottom beam steel bracket (16) are respectively used to fix the top beam, the middle beam and the bottom beam, and the top beam tower connecting steel bars, the middle beam tower connecting steel bars and the bottom beam tower connecting steel bars are respectively used to overlap with the reserved steel bars of the top beam, the middle beam and the bottom beam.

5. The method for constructing the main structure of an assembled subway station based on the cover-excavation reverse construction method according to claim 4 is characterized in that: The prefabricated pile column top is pre-embedded with a grouting sleeve for connection with the top beam.

6. The method for constructing the main structure of an assembled subway station based on the cover-excavation top-down method according to claim 1 is characterized in that: The bottom plate (18) is cast in situ, and the top beam (6), top plate (7), middle beam (12), and middle plate (13) are all prefabricated.

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