Fabricated subway station main body structure construction method based on cover-excavation top-down construction method

Abstract

The invention discloses an assembly type subway station main body structure construction method based on a cover-excavation top-down construction method. Comprising the steps of underground diaphragm wall construction, upper covering soil excavation and pile position drilling, prefabricated pile construction, prefabricated top beam lifting and placing, prefabricated top plate lifting and placing, top beam plate-column joint post-pouring, top plate-side wall joint post-pouring, upper covering soil backfilling, negative first layer earthwork excavation, prefabricated middle beam lifting and placing, prefabricated middle plate lifting and placing, middle beam plate-column joint post-pouring and middle plate-side wall joint post-pouring. Excavating a negative second layer earthwork, pouring a bottom plate cushion layer, prefabricating a bottom beam in place and suspending, binding bottom plate steel bars, post-pouring a bottom plate, and post-pouring a bottom beam column node. A bottom plate is cast in place, a top beam, a top plate, a longitudinal beam and a floor slab are fully prefabricated, and an underground continuous wall and a prefabricated pile serve as temporary enclosure components and also serve as permanent vertical supporting components; and only a simple template needs to be erected, and after the top plate is mounted, the covering soil is backfilled to restore the road surface, so that the construction period is greatly shortened, and the influence of construction on urban traffic and environment is reduced to the minimum.

Description

Technical Field

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

[0002] With the rapid development of my country's social economy and the continuous acceleration of urbanization, urban underground rail transit has become the only choice to solve the current traffic congestion problem. The construction technology of the subway station with cover and excavation reverse construction not only has little impact on ground traffic, but also can greatly reduce the impact of noise and dust on the surrounding environment. In addition, the overall structural system of the cover and excavation reverse construction station has high lateral stiffness, which can better control the deformation of the foundation pit and the settlement of surrounding buildings and the ground during the excavation process. Therefore, it has good application value and has been widely promoted.

[0003] Traditional cover-excavation-reverse construction subway stations often use traditional full cast-in-place construction technology, which is prone to dust and noise pollution, formwork material consumption, large number of people on the construction site, high labor intensity, and difficult engineering quality control. Therefore, a construction method for prefabricated subway stations based on cover-excavation-reverse construction is obviously 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 subway stations currently constructed by cover-excavation-reverse construction method, the present invention proposes a construction method for the main structure of an assembled subway station based on the cover-excavation-reverse 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 in that it comprises the following steps:

[0006] S1. Conduct underground continuous wall construction, form trenches for the underground continuous wall in the subway station construction area, tie up the underground continuous wall reinforcement cage, and embed a number of sealed rectangular steel pipes from bottom to top in the reinforcement cage, place the underground continuous wall reinforcement cage, and pour the underground continuous wall concrete;

[0007] S2, dig downward from the original ground elevation 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, drive several intermediate pile foundations, hang prefabricated 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, overlap the top beam end reinforcement with the precast pile reserved top beam tower reinforcement, and weld the main reinforcement;

[0009] S4. After the top beam is connected, remove the embedded sealed rectangular steel pipe cover, weld the top beam steel bracket, hang the top plate to the top beam and the upper surface of the top beam steel bracket, overlap the top plate extended steel bars with the reserved U-shaped bars of the underground continuous wall and the top beam U-shaped lap bars, support the simple formwork, and cast the top beam slab-column nodes and the top plate-side wall nodes;

[0010] S5. Backfill the upper covering soil, reserve several top plate areas as the excavation opening, excavate the soil downward to the bottom of the subway station middle plate to the preset height, remove the embedded sealed rectangular steel pipe cover plate, and weld the middle beam steel bracket;

[0011] S6. Hoist the center beam onto the steel bracket of the center beam of the precast pile, overlap the lap steel bars at the end of the center beam with the steel bars reserved for the center beam tower of the precast pile, and weld the main reinforcement;

[0012] S7. Lift the middle plate to the upper surface of the middle beam and the middle beam steel corbel, overlap the middle plate protruding steel bars 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, post-cast the middle beam slab-column nodes, post-cast the middle plate-side wall nodes, and reserve several middle plate areas as the excavation openings;

[0013] S8, dig down 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 bracket;

[0014] S9. The bottom beam is in place and suspended, the lap steel bars at the end of the bottom beam are overlapped with the reserved bottom beam tower connection steel bars of the precast piles, and the main bars are welded;

[0015] S10, perform one-time bottom plate pouring, which does not require the setting up of formwork, pours to the designed elevation, and performs bottom plate concrete curing;

[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 comprises: a steel pipe haunch, a sealing ring, and a U-shaped floor slab lap rib; bolt holes are reserved at the steel pipe haunch for installing the corbel;

[0018] The sealed rectangular steel pipe is sealed at both ends, and the inner cavity of the rectangular steel pipe is connected to the concrete with a steel reinforcement plate; the steel reinforcement plate is provided with a sealing ring to prevent leakage; the U-shaped floor lap rib passes through the holes of the steel reinforcement plate to press the sealing ring and then is welded and fixed on the back. The sealed rectangular steel pipe is provided with a cover plate close to the plate side and a sealing ring away from the plate side to ensure that no soil and concrete enter the inner cavity of the rectangular steel pipe.

[0019] Preferably, the prefabricated pile body 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;

[0020] The top beam steel corbels, middle beam steel corbels and bottom beam steel corbels 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 pre-buried at 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 invention discloses a method for constructing the main structure of an assembled subway station based on the cover-excavation reverse construction method, which can reduce the defects such as dust and noise pollution, template material consumption, large number of people on the construction site, high labor intensity, and difficult engineering quality control caused by the construction. 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] Fig. 9 It is a 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. overlying soil; 9. top beam-slab-column node; 10. top plate-side wall node; 11. middle beam steel corbel; 12. middle beam; 13. middle plate; 14. middle beam-slab-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 solution and advantages of the present invention clearer, the technical solution of the application is further elaborated in detail below in conjunction with 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 the field on this embodiment belong to the protection scope of the present invention. At the same time, for the step numbering in the embodiment of the present invention, it is only set for the convenience of explanation, 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, make trenches for the underground continuous wall in the subway station construction area, tie up the underground continuous wall steel cage, and embed three sealed rectangular steel pipes 2 in the steel cage and seal the rectangular steel pipes, place the underground continuous wall steel cage and pour the underground continuous wall concrete, such as 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, three sealed rectangular steel pipes 2 are arranged from bottom to top at intervals, and each sealed rectangular steel pipe 2 includes: a steel pipe haunch, a sealing ring, and a U-shaped floor slab lap rib; bolt holes are reserved at the steel pipe haunch for installing the corbel.

[0039] Preferably, the sealed rectangular steel tube 2 is sealed at both ends, and a steel bar reinforced steel plate is placed inside the cavity of the rectangular steel tube to connect with the concrete; the steel bar reinforced steel plate is provided with a sealing ring to prevent leakage; the U-shaped floor slab lap ribs pass through the holes of the steel bar reinforced steel plate to press the sealing ring and then are welded and fixed on the back. The sealed rectangular steel tube 2 is provided with a cover plate close to the plate side and a sealing ring away from the plate side to ensure that no soil and concrete enter the inner cavity of the rectangular steel tube to affect the subsequent welding of the plate reinforcement and the reserved U-shaped reinforcement.

[0040] Step 2: Dig down from the original ground elevation 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, Fig. 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 corbels, middle beam steel corbels and bottom beam steel corbels 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 for 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 post-cast the top beam-slab-column nodes 9 and the top plate-side wall nodes 10.

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

[0047] Step 6: Hang the middle beam 12 onto the middle beam steel bracket 11 of the precast pile 3, overlap the beam end lap steel bars with the middle beam tower steel bars reserved for 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 slab-column node 14 and the middle plate-side wall node 15. Figure 6 shown.

[0049] Step 8: Dig down 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 embedded sealed rectangular steel pipe 2 cover plate, and install the bottom beam steel bracket 16.

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

[0051] Step 10: Cast the base plate 18 at one time. The base plate does not need to be cast in formwork. The base plate is cast to the designed elevation and the base plate concrete is cured. 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 main structure construction of the station.

[0053] The invention discloses a method for constructing the main structure of an assembled subway station based on the cover-excavation and top-down construction method, which effectively solves the problems of long construction period, large mold consumption, high labor intensity, etc. of the current subway station using the cover-excavation and top-down construction method. At the same time, the construction period is greatly reduced by increasing the prefabrication rate, thereby minimizing the impact of the 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 principle 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 construction area of ​​the subway station, 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 locating the pile holes, drilling holes to the lower surface of the bottom plate (18), laying a number of intermediate pile foundations (4), hanging and placing prefabricated piles (3) above each intermediate pile foundation (4) to a specified elevation, and hammering and sinking the piles; S3, hoisting the top beam (6) onto the top beam steel bracket (5) of the precast pile (3), overlapping the lap steel bars at the end of the top beam (6) with the top beam tower connection steel bars 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 suspended to the top beam (6) and the upper surface of the top beam steel bracket (5), the top plate (7) is overlapped with the U-shaped reinforcement reserved in the underground continuous wall (1) and the U-shaped overlap reinforcement of the top beam (6), a simple formwork is set up, and the top beam slab-column node (9) and the top plate-side wall node (10) are cast later; S5, backfill the upper covering soil (8), reserve a number of top plate areas as the excavation opening, excavate the soil downward to the bottom of the subway station middle plate (13) to a preset height, remove the cover plate of the embedded sealed rectangular steel pipe (2), 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 steel bars at the end of the middle beam (12) with the steel bars reserved for the middle beam tower 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 overlapping bars of the middle beam (12), setting up a simple formwork, post-casting the middle beam-slab-column node (14) and the post-casting middle plate-side wall node (15), and reserving several middle plate areas as excavation openings; S8, digging downward to the casting surface of the bottom plate (18), making a bottom plate concrete cushion layer on the soil surface of the bottom plate casting surface, tying the bottom plate steel bars, removing the embedded sealed rectangular steel pipe cover plate, and installing the bottom beam steel bracket (16); S9, the bottom beam (17) is in place and suspended, the lap steel bars at the end of the bottom beam (17) are overlapped with the reserved bottom beam tower connection steel bars of the prefabricated pile (3), and the main bars are welded; S10, performing one-time casting of the base plate (18), wherein the base plate casting does not require the setting of a formwork, the base plate is cast to a designed elevation, and the base plate (18) concrete is cured; S11. Set up simple formwork and cast the core area of ​​the beam-column joint of the base plate (18) 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 reverse construction 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 rib; bolt holes are reserved at the steel pipe haunch for installing the corbel; The sealed rectangular steel pipe is sealed at both ends, and a steel bar reinforced steel plate is built into the cavity of the rectangular steel pipe to be connected with concrete; the steel bar reinforced steel plate is provided with a sealing ring to prevent leakage; the U-shaped floor lap ribs pass through the holes of the steel bar reinforced steel plate to press the sealing ring and then are 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 connection steel bar, a bottom beam steel bracket (16), a middle beam steel bracket (11), a middle beam tower connection steel bar, a top beam steel bracket (5), and a top beam tower connection steel bar; The top beam steel bracket (5), the middle beam steel bracket (11) and the bottom beam steel bracket (16) are used to fix the top beam, the middle beam and the bottom beam respectively, and the top beam tower connecting steel bars, the middle beam tower connecting steel bars and the bottom beam tower connecting steel bars are used to overlap with the reserved steel bars of the top beam, the middle beam and the bottom beam respectively.

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 reverse construction 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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