Construction method of a prefabricated subway station with a combination of permanent and temporary structures

Abstract

The application discloses a construction method of a combined permanent and temporary assembly type subway station of a surrounding structure and a main body, which comprises the following steps: first, constructing a prefabricated diaphragm wall, and not arranging a crown beam on the top of adjacent prefabricated diaphragm walls; second, excavating a foundation pit between the adjacent prefabricated diaphragm walls to the top plate structure, and hoisting prefabricated top plate cross box girders as a first support at intervals, and the prefabricated top plate cross box girders are used as a part of the top plate structure in the later period; and third, continuously excavating the foundation pit to the middle plate structure, hoisting two layers of whole prefabricated middle plates as a second support at intervals, connecting the two layers of whole prefabricated middle plates through bolts to form a stress component, and tightly pressing the two ends of the upper whole prefabricated middle plate against the prefabricated diaphragm wall through a jack and a short support. The construction precision is improved by prefabricating each component, the number of joints is small, the stress of a cast-in-place connecting mode is easy to meet, the surrounding structure, the supporting structure and the main body structure are combined, the removal of temporary support is avoided, the production cost is reduced, and the construction period is shortened.

Description

Technical Field

[0001] This invention belongs to the field of underground structural engineering, and in particular relates to a construction method for a prefabricated subway station that combines permanent and temporary enclosure with the main structure. Background Technology

[0002] With national policy support and guidance, the prefabricated construction technology for high-rise buildings has developed rapidly. Whether it's the theory, methods, and technology of prefabricated structures, construction standards, construction equipment, or even the entire prefabricated industry chain, there has been rapid development and it has become relatively mature. In underground engineering, shield tunneling technology, as a mainstream construction method, has a wide range of applications and development fields due to its advantages of safety, speed, and integrated excavation and support structure assembly. However, underground stations are still mainly constructed using cast-in-place reinforced concrete methods. The increasing labor costs and changing skills and physical characteristics of migrant workers pose challenges to the current state of underground structural construction. To meet the needs of high-quality development and innovation-driven development of rail transit, prefabricated construction technology for subway stations will usher in unprecedented development.

[0003] According to incomplete statistics, there are currently 36 prefabricated subway stations completed or under construction in China, including 30 arched stations. Changchun, Shenzhen, and Qingdao have adopted large-span arched fully prefabricated subway station structures, using diaphragm walls for the enclosure structure and backfilling trenches between the main structure's side walls and the diaphragm walls, resulting in higher overall project costs. The roof slabs of Beijing Metro Line 6's Jinanqiao Station, Shanghai Metro's Wuzhong Road Station, and Jinan Metro's Yanmaqiao Station use composite structures. Guangzhou Metro's Shangyong Park Station uses a composite beam + composite slab structure for its middle and roof slabs. These pilot projects use composite slabs instead of traditional cast-in-place formwork, resulting in low assembly rates and low construction efficiency.

[0004] Therefore, we need to design a construction method for prefabricated subway stations that combines the enclosure with the permanent main structure to solve these problems. Summary of the Invention

[0005] The problem this invention aims to solve is to provide a construction method for prefabricated subway stations that combines temporary and permanent structures with enclosures, thereby solving the problem of dismantling temporary supports in traditional construction, achieving a combination of temporary and permanent structures, saving construction costs and reducing expenses.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] A construction method for a prefabricated subway station that combines permanent and temporary enclosure with the main structure includes the following steps:

[0008] The first step is to construct precast diaphragm walls, without installing capping beams on top of adjacent precast diaphragm walls;

[0009] Secondly, excavate the foundation pit to the roof structure between the adjacent precast contiguous walls, and hoist the precast roof transverse box girder as the first support, and the precast roof transverse box girder is used as part of the roof structure later;

[0010] Thirdly, continue to excavate the foundation pit to the middle plate structure, hoist two layers of precast middle plates as the second support, connect the two layers of precast middle plates through bolts to form a force-bearing component, and use the jacks and short supports to tighten the upper layer of precast middle plates at both ends to the precast contiguous walls;

[0011] Fourthly, complete the excavation of the remaining part of the foundation pit, and construct the cast-in-place bottom plate and bottom longitudinal beam at the bottom of the pit;

[0012] Fifthly, hoist the precast middle vertical column on the bottom longitudinal beam, and then hoist the precast middle longitudinal beam between the adjacent two precast middle vertical columns;

[0013] Sixthly, hoist the half-width precast middle plate on both sides of the precast middle vertical column and the remaining whole-width precast middle plate, remove the upper layer of precast middle plate of the second support, and hoist it to the adjacent installation position for installation;

[0014] Seventhly, install the precast roof composite plate between the precast roof transverse box girders, and then construct the cast-in-place top longitudinal beam and the roof waterproofing;

[0015] Eighthly, remove the precast contiguous wall segments above the roof structure, and backfill the overburden.

[0016] Preferably, in the second step, the precast roof transverse box girder is supported on the vertical joints of the adjacent precast contiguous walls, and the support interval of the adjacent precast roof transverse box girders matches the width of the precast contiguous walls.

[0017] In this way, each precast roof transverse box girder can be in contact with the two precast contiguous walls on both sides of the joint, effectively transmitting the force.

[0018] Preferably, the roof bracket structure and the middle plate bracket structure are arranged on the precast contiguous walls, the roof structure is fixedly connected to the precast contiguous walls through the roof bracket structure, the middle plate structure is fixedly connected to the precast contiguous walls through the middle plate bracket structure, and the joints between the roof structure and the roof bracket structure and between the middle plate structure and the middle plate bracket structure are filled and compacted with UHPC concrete.

[0019] In this way, the connection strength of the roof structure, the middle plate structure, and the precast contiguous walls can be ensured.

[0020] Preferably, in the fourth step, before construction, the steel bars in the cast-in-place bottom plate are inserted into the steel bar connectors arranged on the precast contiguous walls, and then the cast-in-place bottom plate is poured with concrete.

[0021] In this way, the connection strength of the cast-in-place bottom plate and the prefabricated ground wall can be ensured.

[0022] Preferably, in the fifth step, the prefabricated middle longitudinal beam is hoisted onto a small trolley on the cast-in-place bottom plate through the interval of the first support and the interval of the second support, the prefabricated middle longitudinal beam is moved to between two adjacent prefabricated middle columns by the trolley, the prefabricated middle longitudinal beam is fixedly installed through the middle column bracket structure on the prefabricated middle column, and the gap between the prefabricated middle longitudinal beam and the prefabricated middle column is filled with UHPC concrete.

[0023] In this way, the prefabricated middle longitudinal beam can support the middle plate structure, so that the middle plate structure is not damaged due to excessive stress.

[0024] Preferably, in the sixth step, when the second support upper layer of the entire prefabricated middle plate is removed, it is not convenient to hoist and construct externally due to the obstruction of the prefabricated top plate transverse box girder, so a hoisting tool is installed at the bottom of the prefabricated top plate transverse box girder to longitudinally move the second support upper layer of the entire prefabricated middle plate and hoist it to the adjacent installation position for installation.

[0025] In this way, the construction efficiency is improved, and the construction progress is accelerated.

[0026] Preferably, in the seventh step, the prefabricated top plate composite slab is installed between adjacent prefabricated top plate transverse box girders, connected through the matching lap bracket on the prefabricated top plate transverse box girder, and connected as a whole through the pouring of filling concrete, the connecting steel bars and truss bars.

[0027] In this way, the strength of the prefabricated top plate composite slab can be improved, and the connection between the prefabricated top plate composite slab and the prefabricated top plate transverse box girder is more firm.

[0028] Preferably, after the entire prefabricated middle plate between the adjacent prefabricated middle columns is laid, the entire prefabricated middle plate is connected and fixed with the prefabricated middle longitudinal beam through connecting bolts.

[0029] In this way, the connection between the middle plate structure and the prefabricated middle longitudinal beam is more firm.

[0030] Preferably, the cast-in-place top longitudinal beam includes an upper cast-in-place top longitudinal beam and a lower cast-in-place top longitudinal beam, the lower cast-in-place top longitudinal beam is located below the prefabricated top plate transverse box girder and fixedly connected with the top of the prefabricated middle column, and the upper cast-in-place top longitudinal beam is located above the prefabricated top plate transverse box girder and fixedly connected with the filling concrete of the prefabricated top plate composite slab.

[0031] In this way, the lower cast-in-place top longitudinal beam can better support the top plate structure, and the upper cast-in-place top longitudinal beam connects the filling concrete with each other, thereby improving the overall strength of the top plate structure.

[0032] The present application has the advantages and positive effects that:

[0033] 1、The present application makes the quality of each component controllable and uniform by prefabricating each component, shortens the construction period, and improves the construction precision.

[0034] 2、The present application combines the foundation pit enclosure, support structure and the side wall of the main structure, realizes permanent and temporary combination, avoids the removal of temporary support, saves the cost, and reduces the production cost.

[0035] 3、The present application reduces the number of joints by connecting standard components, and the joints are mostly cast-in-place joints, which are easy to meet the stress performance and reduce the requirement for assembly precision. BRIEF DESCRIPTION OF DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0037] Figure 1 is a schematic diagram of the overall cross section of the subway station of the present application;

[0038] Figure 2 is a schematic diagram of the cross section along the I-I plane in Figure 1 ;

[0039] Figure 3 is a schematic diagram of the cross section along the II-II plane in Figure 1 ;

[0040] Figure 4 is a schematic diagram of the longitudinal section along the III-III plane in Figure 1 ;

[0041] Figure 5 is a schematic diagram of the longitudinal section along the IV-IV plane in Figure 1 ;

[0042] Figure 6 is a schematic diagram of the connection structure between the roof structure and the prefabricated middle column of the present application;

[0043] Figure 7 is a schematic diagram of the cross section of the prefabricated roof slab of the present application;

[0044] Figure 8 is a schematic diagram of the cross section of the prefabricated pad plate of the present application;

[0045] Figure 9It is the roof bracket structure of the application and the roof structure connection structure schematic diagram;

[0046] Figure 10 It is the middle plate structure connecting seam structure schematic diagram of the application;

[0047] Figure 11 It is the middle plate bracket structure and the middle plate structure connection structure schematic diagram of the application;

[0048] Figure 12 It is the cast-in-place bottom plate and the prefabricated ground wall connection structure schematic diagram of the application;

[0049] Figure 13 It is the first step in the construction method of the application, and the cross section schematic diagram;

[0050] Figure 14 It is the second step in the construction method of the application, and the cross section schematic diagram of the foundation pit excavation;

[0051] Figure 15 It is the second step in the construction method of the application, and the cross section schematic diagram of the first support erection;

[0052] Figure 16 It is the third step in the construction method of the application, and the cross section schematic diagram of the second support erection;

[0053] Figure 17 It is the third step in the construction method of the application, and the cross section schematic diagram of the second support reinforcement;

[0054] Figure 18 It is the fourth step in the construction method of the application, and the cross section schematic diagram of the cast-in-place bottom plate construction;

[0055] Figure 19 It is the fifth step in the construction method of the application, and the cross section schematic diagram of the prefabricated column hoisting construction;

[0056] Figure 20 It is the fifth step in the construction method of the application, and the horizontal cross section schematic diagram of the prefabricated middle longitudinal beam hoisting construction;

[0057] Figure 21 It is the fifth step in the construction method of the application, and the cross section schematic diagram of the prefabricated middle longitudinal beam hoisting construction;

[0058] Figure 22 It is the fifth step in the construction method of the application, and the total cross section schematic diagram of the prefabricated middle longitudinal beam hoisting construction;

[0059] Figure 23 It is the fifth step in the construction method of the application, and the longitudinal cross section schematic diagram after the prefabricated middle longitudinal beam installation is completed;

[0060] Figure 24is a horizontal section schematic diagram of the prefabricated middle beam after the installation is completed in the fifth step of the construction method of the present application;

[0061] Figure 25 is a horizontal section schematic diagram of the remaining middle plate structure hoisting construction in the sixth step of the construction method of the present application;

[0062] Figure 26 is a horizontal section schematic diagram of the remaining middle plate structure hoisting construction in the sixth step of the construction method of the present application;

[0063] Figure 27 is a horizontal section schematic diagram of the remaining middle plate structure hoisting construction in the sixth step of the construction method of the present application;

[0064] Figure 28 is a horizontal section schematic diagram of the remaining middle plate structure hoisting construction in the sixth step of the construction method of the present application.

[0065] The reference signs are explained as follows:

[0066] 1, prefabricated diaphragm wall; 2, cast-in-place bottom plate; 3, bottom longitudinal beam; 4, whole-width prefabricated middle plate; 5, prefabricated top plate cross box beam; 6, prefabricated top plate composite plate; 7, upper cast-in-place top longitudinal beam; 8, prefabricated middle column; 9, prefabricated middle longitudinal beam; 10, top plate cast-in-place layer; 11, top plate bracket structure; 12, middle plate bracket structure; 13, middle column bracket structure; 14, steel bar adapter; 15, connecting bolt; 16, earth covering; 17, foundation pit; 18, UHPC concrete; 19, lap bracket; 20, half-width prefabricated middle plate; 21, jack; 22, filling concrete; 23, rough surface; 24, caulking sealant; 25, connecting steel bar; 26, truss bar; 27, lower cast-in-place top longitudinal beam. DETAILED DESCRIPTION

[0067] In the description of the present application, it needs to be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second" and the like are only for description purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" and the like can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise stated, the meaning of "a plurality of" is two or more.

[0068] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0069] All standard parts used in this invention can be purchased from the market, and irregular parts can be customized according to the description and drawings. The specific connection methods of each part adopt conventional methods such as bolts, rivets, and welding that are mature in the prior art. The machinery, parts and equipment adopt conventional models in the prior art, and the circuit connection adopts conventional connection methods in the prior art, which will not be described in detail here.

[0070] The present invention will be further described below with reference to the accompanying drawings:

[0071] Example 1

[0072] like Figures 1-28 As shown, a construction method for a prefabricated subway station that combines enclosure and main structure includes several prefabricated diaphragm walls 1 arranged opposite each other. Between two sets of prefabricated diaphragm walls 1, a cast-in-place base slab 2, a middle slab structure, and a top slab structure are fixedly installed from bottom to top. Several prefabricated central columns 8 are installed on the cast-in-place base slab 2. The tops of the prefabricated central columns 8 pass through the middle slab structure and are fixedly connected to the top slab structure. A prefabricated longitudinal beam 9 is also fixedly installed between two adjacent prefabricated central columns 8. The prefabricated longitudinal beam 9 is fixedly connected to the middle slab structure, and its two ends are fixedly connected to the adjacent prefabricated central columns 8 respectively.

[0073] Specifically, a middle slab corbel structure 12 and a top slab corbel structure 11 are provided on the precast diaphragm wall 1. The top slab structure is fixedly connected to the precast diaphragm wall 1 through the top slab corbel structure 11, and the middle slab structure is fixedly connected to the precast diaphragm wall 1 through the middle slab corbel structure 12. The joints between the top slab structure and the top slab corbel structure 11 and the middle slab structure and the middle slab corbel structure 12 are filled with UHPC concrete 18 to ensure the connection strength between the components.

[0074] Specifically, a steel bar connector 14 is installed on the precast diaphragm wall 1. Before construction, the two ends of the steel bar are inserted into the steel bar connector 14 and fixedly connected to the precast diaphragm wall 1. Then, the cast-in-place base slab 2 is poured with concrete, and a bottom longitudinal beam 3 is fixedly installed on the cast-in-place base slab 2.

[0075] Specifically, the middle plate structure includes a half-width precast middle plate 20 and a full-width precast middle plate 4. The full-width precast middle plate 4 is located between two adjacent precast middle columns 8 and is fixedly connected to the precast middle longitudinal beam 9 by connecting bolts 15. The half-width precast middle plate 20 is located on both sides of the precast middle column 8, with one end fixedly connected to the precast diaphragm wall 1 and the other end fixedly connected to the precast middle column 8. UHPC concrete 18 is used to fill the joints.

[0076] Specifically, the top slab structure includes alternating precast top slab horizontal box beams 5 and precast top slab composite slabs 6. Matching lapped corbels 19 are provided at the connection between the precast top slab horizontal box beams 5 and the precast top slab composite slab 6. The precast top slab composite slab 6 is connected to the precast top slab horizontal box beams 5 through the lapped corbels 19. Connecting steel bars 25 are provided on the precast top slab horizontal box beams 5. Truss bars 26 are provided on the top of the precast top slab composite slab 6. The connecting steel bars 25 and the truss bars 26 are cast and fixed together by filling concrete 22. This arrangement has lower requirements for assembly accuracy, while ensuring construction progress and enhancing the strength of the precast top slab composite slab 6.

[0077] In this embodiment, the bottom of the precast intermediate column 8 is fixedly connected to the bottom longitudinal beam 3, and a cast-in-place top longitudinal beam 7 is also provided on the top of the precast intermediate column 8. The cast-in-place top longitudinal beam 7 includes an upper cast-in-place top longitudinal beam 7 and a lower cast-in-place top longitudinal beam 27. The upper cast-in-place top longitudinal beam 7 is located above the precast top slab transverse box beam 5, and the lower cast-in-place top longitudinal beam 27 is located below the precast top slab transverse box beam 5 and is fixedly connected to the top of the precast intermediate column 8.

[0078] The construction process in this embodiment:

[0079] First step, such as Figure 13 As shown, the precast diaphragm wall 1 is assembled using a mud slurry wall forming method. After the precast diaphragm wall 1 is assembled, no capping beam is installed on the top of the connected precast diaphragm walls 1.

[0080] The second step, as Figure 14 As shown, after the precast diaphragm wall 1 is constructed, the foundation pit 17 is excavated between two adjacent precast diaphragm walls 1. Excavation stops after the foundation pit 17 reaches the depth of the first support. Figure 15 As shown, the first support is erected between the precast diaphragm walls 1. Before erecting the first support, the top slab corbel structure 11 is first installed on the precast diaphragm walls 1. Then, the precast top slab transverse box beams 5 are fixed to the top slab corbel structure 11 at intervals. UHPC concrete 18 is used to fill the gap between the precast top slab transverse box beams 5 and the precast diaphragm walls 1; and as shown... Figure 3As shown, both ends of each precast top slab horizontal box girder 5 are supported on the vertical connection joint of the precast diaphragm wall 1, so that each supported precast top slab horizontal box girder 5 can contact the two precast diaphragm walls 1 on both sides of the joint, effectively transferring the force. At the same time, the distance between adjacent precast top slab horizontal box girders 5 matches the width of the precast diaphragm wall 1, and the precast top slab horizontal box girder 5 will be used as part of the top slab structure of the ground station in the later stage.

[0081] The third step, as Figure 16 As shown, after the first support is erected, the excavation of the foundation pit 17 continues downward. Excavation stops again after reaching the depth of the second support, and the second support is erected. A mid-slab corbel structure 12 is installed on the diaphragm wall where the second support is to be erected. The second support also uses an intermittent method, first installing a layer of precast mid-slab 4 on the mid-slab corbel structure 12. The joint between the precast mid-slab 4 and the precast diaphragm wall 1 is filled with UHPC concrete 18. The precast mid-slab 4 will later be used as part of the mid-slab structure of the subway station, such as... Figure 17 As shown, another layer of precast slab 4 is superimposed on the already installed precast slab 4, and the upper and lower precast slabs 4 are fixedly connected by connecting bolts 15 to form a load-bearing component. Simultaneously, jacks 21 and short braces are used at both ends of the upper precast slab 4 to press the precast diaphragm wall 1 and the precast slab 4 together to form a load-bearing system, thus supporting the precast diaphragm wall 1. Meanwhile, as... Figure 20 As shown, the precast middle slab 4, which serves as the second support, and the precast top slab transverse box beam 5, which serves as the first support, both rest on the vertical connection joint of the precast diaphragm wall 1.

[0082] Step four, as Figure 18 As shown, the remaining part of the foundation pit 17 is then excavated. After the foundation pit 17 is excavated, a cushion layer is laid at the bottom of the foundation pit 17, and then the reinforcing steel of the cast-in-place base slab 2 is arranged, as shown. Figure 12 As shown, the two ends of the reinforcing bars of the cast-in-place base slab 2 need to be connected to the precast diaphragm wall 1 through the precast reinforcing bar connectors 14 reserved on the precast diaphragm wall 1 to ensure that the cast-in-place base slab 2 is firmly connected to the precast diaphragm wall 1. Then, the casting of the cast-in-place base slab 2 is completed, and the bottom longitudinal beam 3 is constructed on the cast-in-place base slab 2.

[0083] Step 5, as Figure 19 As shown, after the bottom longitudinal beam 3 is constructed, several precast intermediate columns 8 are hoisted from the intervals of the first support and the second support into the foundation pit 17 using a crane. The bottom of the precast intermediate columns 8 and the reserved connection nodes of the bottom longitudinal beam 3 are then installed and fixed. Then, as shown... Figure 21 As shown, the prefabricated longitudinal beam 9 is then hoisted, as follows: Figure 22 , Figure 23 , Figure 24As shown, the prefabricated middle longitudinal beam 9 needs to be first lifted from the first support interval and the second support to the foundation pit 17, then rotated by ninety degrees and placed on the small trolley on the cast-in-place floor 2, and then moved to the position between the adjacent prefabricated middle columns 8 by moving the small trolley, and finally connected to the middle column bracket structure 13 on the prefabricated middle column 8.

[0084] The sixth step is to install the remaining part of the middle plate structure after the installation of the prefabricated middle longitudinal beam 9. The crane needs to lift the remaining whole prefabricated middle plate 4 and half prefabricated middle plate 20 into the foundation pit 17, install the whole prefabricated middle plate 4 between the adjacent prefabricated middle columns 8, and install the half prefabricated middle plate 20 on both sides of the prefabricated middle column 8. Since the prefabricated roof transverse box beam 5 blocks the way, the whole prefabricated middle plate 4 as the second support force component cannot be easily disassembled, so as shown, a lifting tool needs to be installed at the bottom of the prefabricated roof transverse box beam 5, and after the connecting bolt 15 is removed, the upper whole prefabricated middle plate 4 is lifted to the adjacent middle plate structure installation position for installation. Figure 25 As shown, the two sides of the whole prefabricated middle plate 4 and the half prefabricated middle plate 20 are rough surfaces 23, and the UHPC concrete 18 is filled between the two rough surfaces 23, and the caulking sealant 24 is arranged at the joint of the plate surface for waterproof sealing. Figure 2 、 Figure 26 As shown, after the installation of the whole prefabricated middle plate 4 and the half prefabricated middle plate 20 is completed, the whole prefabricated middle plate 4 is connected to the prefabricated middle longitudinal beam 9 through the connecting bolt 15. As shown, the two sides of the whole prefabricated middle plate 4 and the half prefabricated middle plate 20 are rough surfaces 23, and the UHPC concrete 18 is filled between the two rough surfaces 23, and the caulking sealant 24 is arranged at the joint of the plate surface for waterproof sealing. Figure 10

[0085] As shown, after the installation of the middle plate structure is completed, the prefabricated roof composite plate 6 is lifted by the crane between the adjacent prefabricated roof transverse box beams 5, assembled and connected through the matching lap bracket 19 on the prefabricated roof transverse box beam 5, and then the prefabricated roof composite plate 6 is filled with concrete 22 above the prefabricated roof composite plate 6. After the filling concrete 22 is solidified, the prefabricated roof transverse box beam 5 and the prefabricated roof composite plate 6 are connected as a whole through the connecting steel bars 25 and the truss bars 26, and then the lower cast-in-place top longitudinal beam 27 is poured on the top of the prefabricated middle column 8, the upper cast-in-place top longitudinal beam 7 is poured above the prefabricated roof transverse box beam 5, and the upper cast-in-place top longitudinal beam 7 is connected to the filling concrete 22 on the prefabricated roof composite plate 6. Figure 27 、 Figure 3 As shown, after the installation of the middle plate structure is completed, the prefabricated roof composite plate 6 is lifted by the crane between the adjacent prefabricated roof transverse box beams 5, assembled and connected through the matching lap bracket 19 on the prefabricated roof transverse box beam 5, and then the prefabricated roof composite plate 6 is filled with concrete 22 above the prefabricated roof composite plate 6. After the filling concrete 22 is solidified, the prefabricated roof transverse box beam 5 and the prefabricated roof composite plate 6 are connected as a whole through the connecting steel bars 25 and the truss bars 26, and then the lower cast-in-place top longitudinal beam 27 is poured on the top of the prefabricated middle column 8, the upper cast-in-place top longitudinal beam 7 is poured above the prefabricated roof transverse box beam 5, and the upper cast-in-place top longitudinal beam 7 is connected to the filling concrete 22 on the prefabricated roof composite plate 6.

[0086] As shown, after the installation of the middle plate structure is completed, the prefabricated roof composite plate 6 is lifted by the crane between the adjacent prefabricated roof transverse box beams 5, assembled and connected through the matching lap bracket 19 on the prefabricated roof transverse box beam 5, and then the prefabricated roof composite plate 6 is filled with concrete 22 above the prefabricated roof composite plate 6. After the filling concrete 22 is solidified, the prefabricated roof transverse box beam 5 and the prefabricated roof composite plate 6 are connected as a whole through the connecting steel bars 25 and the truss bars 26, and then the lower cast-in-place top longitudinal beam 27 is poured on the top of the prefabricated middle column 8, the upper cast-in-place top longitudinal beam 7 is poured above the prefabricated roof transverse box beam 5, and the upper cast-in-place top longitudinal beam 7 is connected to the filling concrete 22 on the prefabricated roof composite plate 6. Figure 28 ​As shown, after the completion of the top plate structure construction, the top plate structure needs to be waterproofed, then the basin method is used to backfill the earth covering 16 on the top plate structure, at the same time, the prefabricated ground wall 1 segment above the top plate structure is removed, and the waterproof treatment after removal is completed, finally, the remaining earth covering 16 is backfilled, and the road surface is restored.

[0087] The above has described one embodiment of the present application in detail, but the content described is only the preferred embodiment of the present application, and cannot be considered as used for limiting the implementation range of the present application. Any equivalent changes and improvements made according to the application scope of the present application should still belong to the patent coverage range of the present application.

Claims

1. A construction method for a prefabricated subway station that combines permanent and temporary enclosure with the main structure, characterized in that, Includes the following steps: The first step is to construct precast diaphragm walls, without installing capping beams on top of adjacent precast diaphragm walls; The second step is to excavate a foundation pit between adjacent precast diaphragm walls down to the top slab structure, and then hoist precast top slab horizontal box beams at intervals as the first support. These precast top slab horizontal box beams will later be used as part of the top slab structure. The third step is to continue excavating the foundation pit to the middle slab structure, and hoist two layers of whole precast middle slabs at intervals as the second support. The two layers of whole precast middle slabs are connected by bolts to form a load-bearing component, and the two ends of the upper whole precast middle slab are tightened to the precast ground wall by jacks and short braces. The fourth step is to complete the excavation of the remaining part of the foundation pit and construct the cast-in-place bottom slab and bottom longitudinal beams at the bottom of the pit. The fifth step is to hoist the precast central column onto the bottom longitudinal beam, and then place the precast central longitudinal beam between two adjacent precast central columns. The sixth step is to hoist the half-width precast slabs on both sides of the precast central column and the remaining full-width precast slabs, while simultaneously removing the upper full-width precast slabs of the second support and hoisting them to the nearest installation position for installation. Step 7: Install precast roof slab composite slabs between the precast roof slab transverse box beams, and then carry out the construction of cast-in-place roof longitudinal beams and roof slabs; Step 8: Remove the precast diaphragm wall segment above the roof slab structure, carry out waterproofing construction on the roof slab, and backfill with soil; The precast diaphragm wall is equipped with a top slab corbel structure and a middle slab corbel structure. The top slab structure is fixedly connected to the precast diaphragm wall through the top slab corbel structure, and the middle slab structure is fixedly connected to the precast diaphragm wall through the middle slab corbel structure. The joints between the top slab structure and the top slab corbel structure and between the middle slab structure and the middle slab corbel structure are all filled with UHPC concrete to make them dense. In the fourth step, before construction, the two ends of the steel bars in the cast-in-place base slab are inserted into the steel bar connectors set on the precast ground diaphragm wall, and then the cast-in-place base slab is poured with concrete. In step seven, the precast roof slab composite slab is installed between adjacent precast roof slab transverse box beams and connected by lap brackets that match the precast roof slab transverse box beams. The precast roof slab transverse box beams and precast roof slab composite slabs are connected as a whole by pouring infill concrete in conjunction with connecting steel bars and truss bars.

2. The construction method of a prefabricated subway station combining permanent and temporary enclosure with main structure according to claim 1, characterized in that: In the second step, the precast top slab horizontal box girder is supported on the vertical connection joint of the adjacent precast diaphragm wall, and the support interval of the adjacent precast top slab horizontal box girder matches the width of the precast diaphragm wall.

3. The construction method for a prefabricated subway station combining permanent and temporary enclosure with the main structure as described in claim 1, characterized in that: In the fifth step, the precast longitudinal beams are hoisted onto a small trolley on the cast-in-place base slab through the intervals of the first and second supports. The trolleys are then used to move the precast longitudinal beams between two adjacent precast columns. The precast longitudinal beams are then fixed in place by the corbel structure on the precast columns, and the gaps between the precast longitudinal beams and the precast columns are filled with UHPC concrete.

4. The construction method of a prefabricated subway station combining permanent and temporary enclosure with main structure according to claim 1, characterized in that: In the sixth step, when dismantling the upper layer of the precast middle slab of the second support, the obstruction of the precast top slab transverse box girder makes external hoisting construction inconvenient. Therefore, it is necessary to install hoisting tools at the bottom of the precast top slab transverse box girder to move the upper layer of the precast middle slab of the second support longitudinally and hoist it to a nearby installation position for installation.

5. A construction method for a prefabricated subway station combining permanent and temporary enclosure with the main structure as described in claim 4, characterized in that: After the entire precast slab between adjacent precast columns is laid, the entire precast slab is connected and fixed to the precast longitudinal beam using connecting bolts.

6. The construction method of a prefabricated subway station combining permanent and temporary enclosure with main structure according to claim 1, characterized in that: The cast-in-place top longitudinal beam includes an upper cast-in-place top longitudinal beam and a lower cast-in-place top longitudinal beam. The lower cast-in-place top longitudinal beam is located below the precast top slab transverse box beam and is fixedly connected to the top of the precast intermediate column. The upper cast-in-place top longitudinal beam is located above the precast top slab transverse box beam and is fixedly connected to the concrete filled on the precast top slab composite plate.

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