Subway station structure based on large shield underneath passing existing line section and construction method

Abstract

The invention discloses a metro station structure based on a large shield underneath passing existing line section and a construction method, the metro station structure comprises a first underground station hall layer, a second underground equipment layer, a third underground platform layer, a first existing line, a second newly-built line and a third long-term planning transfer line, the second newly-built line underneath passing existing line, the second newly-built line is perpendicular to or obliquely crossed with the third long-term planned transfer line, and the first underground floor station hall layer, the second underground floor equipment layer and the third underground floor platform layer are vertically arranged; the construction method comprises the following steps that open excavation construction is conducted at the two ends of the station; the construction method comprises the steps of constructing a shield tunnel, excavating the shield tunnel, constructing an ascending line L2 of a second new line, constructing a descending line L2'of the second new line, constructing a platform plate in the tunnel, constructing a rail top air duct in the tunnel, excavating a pipe-jacking tunnel and connecting a station hall layer of a station.. The construction method has the advantages that the influence on the existing line is small, the construction is fast, the investment is saved, and the adaptability of rail traffic construction is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of rail transit construction, and in particular relates to a subway station structure and a construction method based on a large shield machine passing through an existing line section. Background Art

[0002] With the rapid expansion and interweaving of the domestic rail transit network, the construction of new lines faces unprecedented challenges: the design complexity has increased sharply, and the construction risks have risen sharply. Especially in the context of accelerated urbanization, the uneven urban development and the high cost of reserving space make it difficult for existing lines to effectively foresee and reserve conditions for future expansion. In order to pursue efficient transfers, new line stations often need to be laid out across existing operating intervals. This layout strategy puts forward dual requirements for ensuring the stability of the new line structure and the safety of existing line operations.

[0003] At present, although mining methods, shield methods and other technologies have been applied in the construction of new sections under existing stations, there is still a lack of construction methods for new stations to directly pass under existing lines. In view of the variability of geological conditions, considerations of tunnel bearing capacity and strict requirements for vibration control, this type of construction is very likely to disturb the stability of the existing line structure, especially in geologically complex areas, where its risks, difficulties and costs have increased significantly. Although the shield method has become the first choice due to its technical advantages, it faces spatial limitations in station construction - the size of the shield makes it difficult to arrange passenger service facilities (such as escalators) and equipment rooms, and the shield segment opening technology is difficult and risky. It seems that relying solely on the shield method to implement the underpass construction is beyond one's ability.

[0004] Therefore, it is particularly important to develop an innovative construction method that aims to safely and efficiently pass through and construct subway stations under existing operating line sections where no station crossing conditions are reserved using large shield technology. Summary of the invention

[0005] The present invention is proposed to solve the problems existing in the prior art, and its purpose is to provide a subway station structure and a construction method based on a large shield machine passing through an existing line section.

[0006] The technical solution of the present invention is: a subway station structure based on a large shield tunneling under an existing line section, including an underground first floor station hall layer, an underground second floor equipment layer, an underground third floor platform layer, an existing line one, a newly built line two, and a long-term planned transfer line three, the newly built line two passes under the existing line one, the newly built line two is perpendicular or obliquely intersected with the long-term planned transfer line three, and the underground first floor station hall layer, the underground second floor equipment layer, and the underground third floor platform layer are arranged vertically.

[0007] Furthermore, the underground first floor station hall layer includes a station hall public area and equipment management room areas at both ends of the underground first floor. The station hall public area includes a left station hall space and a right station hall space. A top pipe tunnel is formed between the left station hall space and the right station hall space to connect the two.

[0008] Furthermore, the pipe-jacking tunnel crosses over the existing line 1, and the left station hall space is larger than the right station hall space.

[0009] Furthermore, a transfer hall node is set at the intersection of the right-side station hall space and the long-term planned transfer line three.

[0010] Furthermore, the second underground equipment layer includes a second underground equipment management room area, and the second underground equipment management room area includes a left equipment space and a right equipment space, and the left equipment space and the right equipment space are separated by an existing line.

[0011] Furthermore, the underground third-level platform layer includes a middle public area and equipment management room areas at both ends of the underground third level. The shield tunnel of the underground third-level platform layer passes under the existing line 1, and the underground third-level platform layer includes a left platform space and a right platform space.

[0012] Furthermore, the shield tunnel strives for shorter transfer distances and should be within the safety distance range on both sides of the existing line. The safety distance range refers to the working point distance between the two sets of escalators on the platform level of the station being less than 100 meters. This can avoid the risk of breaking the shield segments due to adding evacuation facilities in the shield tunnel.

[0013] The construction method of a subway station structure based on a large shield tunnel passing through an existing line section includes the following steps:

[0014] A. Open-cut construction is carried out at both ends of the station to build the main structure of the station;

[0015] B. Excavation of shield tunnels, construction of the new second up line and the new second down line;

[0016] C. Platform slab in the construction tunnel;

[0017] D. Rail top air duct in the construction tunnel;

[0018] E. Excavate a pipe-jacking tunnel to connect the station concourse level.

[0019] Furthermore, step A carries out open excavation construction at both ends of the station to construct the main structure of the station. The specific process is as follows:

[0020] First, in the open-cut section of the subway station, the foundation pit is excavated using the open-cut method. The retaining structure is constructed first, and then the multi-layer support structure is set up in sequence as the excavation progresses.

[0021] Then, the main structure of the station is constructed, including the pouring of the station floor, station side walls, station middle plate, and station roof;

[0022] After that, the support structures are dismantled in turn.

[0023] Finally, backfill the soil.

[0024] Furthermore, in step B, the construction of the new line 2 up line is as follows:

[0025] First, construct the starting shaft of the up line L2, the receiving shaft of the up line L2, the starting shaft of the down line L2', and the receiving shaft of the down line L2' at both ends of the shield section of the subway station;

[0026] Then, the shield segments with steel plates or shield segments with embedded reinforcement are constructed;

[0027] Finally, the large shield is hoisted in from the starting well of the upline L2, the shield is advanced and the shield segments are assembled; after the construction is completed, it is hoisted out from the receiving well of the upline L2.

[0028] Furthermore, in step B, the second down line of the new line is constructed, and the specific process is as follows:

[0029] First, the large shield machine was transferred to the starting shaft of the downline L2' and hoisted in;

[0030] Then, the shield segments with steel plates or shield segments with embedded reinforcement are constructed;

[0031] Finally, the shield machine is advanced and the shield segments are assembled. After the construction is completed, it is hoisted out from the receiving shaft of the downline L2' to complete the excavation of the shield tunnel.

[0032] The beneficial effects of the present invention are as follows:

[0033] The present invention minimizes the impact on existing lines, ensures the continuous and stable operation of existing lines, significantly improves the construction speed, and effectively shortens the project period. In addition, the present invention greatly reduces the distance between the new station and the existing line section structure, and reduces the structural burial depth of the station that does not pass under the existing line, which not only reduces the project risk, but also achieves significant savings in investment costs.

[0034] The present invention overcomes the space limitations of newly built stations and optimizes the passenger flow design. It can not only solve the problem of platforms crossing existing line sections, but also achieve efficient and comfortable use of most of the space in newly built stations. It can also avoid damage to shield segments to reduce engineering risks, and provide a broader range of ideas and options for the design of subway stations for newly built urban rail transit lines.

[0035] The present invention integrates the essence of various technologies such as open-cut method, pipe jacking method, shield method, etc. to form a comprehensive solution, which provides strong technical support for the construction of new stations crossing existing line sections in the future, greatly enhances the flexibility and adaptability of rail transit construction, and lays a solid foundation for the sustainable development of urban rail transit. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is the plan layout of the underground floor of the station in the present invention;

[0037] Figure 2 It is the plan layout of the second underground floor of the station in the present invention;

[0038] Figure 3 The plan layout of the three underground floors of the station in the present invention;

[0039] Figure 4 It is a longitudinal section diagram of the station in the present invention;

[0040] Figure 5 It is a cross-sectional view of the station in the present invention;

[0041] Figure 6 This is a plan view of the shield tunnel under the existing line section of the present invention;

[0042] Figure 7 This is a cross-sectional view of the shield tunnel of the present invention;

[0043] Figure 8 This is a circumferential arrangement diagram of the embedded steel plate and anchor bars of the present invention;

[0044] Fig. 9 This is a schematic diagram of the pre-embedded steel plate and anchor bars of the pipe segment of the present invention;

[0045] in:

[0046] L1 existing line - up line section L1' existing line down line section

[0047] L2 New Line 2 Up Line L2' New Line 2 Down Line

[0048] L3 long-term planning transfer line three up line

[0049] L3' long-term planning transfer line three down line

[0050] 4 Pipe-jacking tunnel 5 Shield tunnel

[0051] 6 Transfer Hall Node 7 New Station Main Body on the Left

[0052] 8 Newly built station on the right 9 Station hall space on the left

[0053] 10Right side hall space 11Left side equipment space

[0054] 12 Equipment space on the right 13 Platform space on the left

[0055] 14 Right platform space 15 Up line L2 starting shaft

[0056] 16 Up line L2 receiving well 17 Down line L2' starting well

[0057] 18 Downline L2' receiving shaft 19 rail top air duct

[0058] 20 platform plate 21 track layer

[0059] 22 Driving profile 23 Embedded steel plate at rail top air duct

[0060] 24 Anchor reinforcement at the track top air duct 25 Embedded steel plate at the platform plate

[0061] 26 anchor bars at platform slab, 27 shield segments. DETAILED DESCRIPTION

[0062] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings and embodiments:

[0063] like Figures 1 to 9 As shown, the structure of the subway station based on the large shield passing under the existing line section includes the first underground station hall layer, the second underground equipment layer, the third underground platform layer, the existing line one, the new line two, and the long-term planned transfer line three. The new line two passes under the existing line one, and the new line two is perpendicular or oblique to the long-term planned transfer line three. The new line two subway station structure includes the left station body 7 and the right station body 8 of the existing line one. The first underground station hall layer, the second underground equipment layer, and the third underground platform layer are arranged vertically.

[0064] The underground first floor station hall layer includes a station hall public area and equipment management room areas at both ends of the underground first floor. The station hall public area includes a left station hall space 9 and a right station hall space 10. A pipe jacking tunnel 4 is formed between the left station hall space 9 and the right station hall space 10 to connect the two.

[0065] The pipe-jacking tunnel 4 crosses over the existing line 1, and the left station hall space 9 is larger than the right station hall space 10.

[0066] A transfer hall node 6 is arranged at the intersection of the right side hall space 10 and the long-term planned transfer line three.

[0067] The second underground equipment layer includes a second underground equipment management room area, and the second underground equipment management room area includes a left equipment space 11 and a right equipment space 12. The left equipment space 11 and the right equipment space 12 are separated by an existing line.

[0068] The underground third-level platform layer includes a middle public area and equipment management room areas at both ends of the underground third level. The shield tunnel 5 in the underground third-level platform layer passes under the existing line 1, and the underground third-level platform layer includes a left platform space 13 and a right platform space 14.

[0069] Specifically, the existing line 1 includes an existing line 1 up line section L1 and an existing line 1 down line section L1', and the existing line 1 up line section L1 and the existing line 1 down line section L1' are arranged in an existing underground section tunnel. A top pipe tunnel 4 is arranged above the existing underground section tunnel, and a shield tunnel 5 is arranged below the existing underground section tunnel.

[0070] Specifically, when the underground concourse layer is connected, the jacking method is used to cross the existing line section, and the concourses on both sides are connected through a rectangular jacking tunnel. The jacking method affects the architectural layout of the station concourse. When the underground concourse layer is connected by a jacking pipe, the escalator layout needs to comprehensively consider the passenger flow organization of the entire concourse to meet the functional requirements of entering and exiting the station. When the concourse layer is not connected by a jacking pipe, the concourse layer will be divided into two independent parts.

[0071] Specifically, the underground second-floor equipment layer is set up as an independent layer below the underground first-floor station hall layer in consideration of saving the scale of the main body of the new station. Due to the existence of the existing line section, the equipment layer is divided into two independent parts.

[0072] Specifically, the underground three-story platform layer is connected to the main station structure on both sides through a shield shaft. The shield diameter size needs to meet the needs of the internal facilities and equipment of the shield section platform under the limitation of vertical height, including the space required for the side platform, track area and top plate equipment pipelines. According to the fire protection regulations, the length of the shield section cannot cause the evacuation distance between the two sets of escalator working points on the station platform layer to exceed 100m.

[0073] Specifically, the newly built line 2 includes a newly built line 2 up line L2 and a newly built line 2 down line L2', and the long-term planned transfer line 3 includes a long-term planned transfer line 3 up line L3 and a long-term planned transfer line 3 down line L3'.

[0074] Specifically, the middle part of the underground first-floor station hall layer spans a section area of ​​the existing line, and two 8.1m wide top pipe tunnels 4 are used to connect the left station hall space 9 and the right station hall space 10. Three sets of escalators are evenly arranged in the left station hall space 9, and one set of double escalators is arranged in the right station hall space 10 to meet the short-term entry and exit and long-term transfer function requirements.

[0075] Specifically, the equipment floor of the second underground floor is the equipment management room area. Due to the existence of the existing line 1, the station equipment management room area is divided into two independent spaces, namely the left equipment space 11 and the right equipment space 12. The right equipment space 12 is reserved for the planned line 3 interval crossing area. An independent safety entrance and exit to the ground is set near the left end of the shield shaft in the left equipment space 11 area.

[0076] Specifically, the 8.8m diameter shield tunnel is used for the platform under the existing line 1 area in the underground three-story platform layer, and the width of the shield tunnel section connecting the underground three-story platform is 3m. There are four escalator groups leading to the station hall from the effective platform. Three sets of double escalators are set on the left side of the existing line 1 section, and one set of double escalators is set on the left side of the existing line 1 section to serve the passenger flow entering and leaving the station on the north side, as well as the passenger flow of the transfer line 3 in the long term and the long-term planning transfer line.

[0077] There is a vertical elevator leading to the hall level near the end wall of the shield section and the open-cut section. This allows the station of the new Line 2 to be built quickly without affecting the operation of the existing Line 1, and also reserves flexible implementation conditions for the long-term planning of the transfer Line 3, further improving the efficiency and safety of the project and reducing the cost and environmental impact of the project.

[0078] The construction method of the subway station structure based on a large shield tunnel passing through an existing line section includes the following steps:

[0079] A. Open-cut construction is carried out at both ends of the station to build the main structure of the station;

[0080] B. Excavation of shield tunnels, construction of the new line 2 up line L2 and the new line 2 down line L2';

[0081] C. Platform plate 20 in the construction tunnel;

[0082] D. Rail top air duct 19 in the construction tunnel;

[0083] E. Excavate the jacking tunnel 4 to connect the station concourse level.

[0084] Step A involves open excavation at both ends of the station to construct the main structure of the station. The specific process is as follows:

[0085] First, in the open-cut section of the subway station, the foundation pit is excavated using the open-cut method. The retaining structure is constructed first, and then the multi-layer support structure is set up in sequence as the excavation progresses.

[0086] Then, the main structure of the station is constructed, including the pouring of the station floor, station side walls, station middle plate, and station roof;

[0087] After that, the support structures are dismantled in turn.

[0088] Finally, backfill the soil.

[0089] Step B constructs the new line 2 up line L2, the specific process is as follows:

[0090] First, construct the starting shaft 15 of the up line L2, the receiving shaft 16 of the up line L2, the starting shaft 17 of the down line L2', and the receiving shaft 18 of the down line L2' at both ends of the shield tunnel section of the subway station;

[0091] Then, the pre-buried steel plate of the platform plate is manufactured and installed, and the pre-buried steel plate 25 of the platform plate with a thickness of 16 mm is processed to adapt to the shape and structure of the shield segment 27;

[0092] Then, the φ12 anchor bars 26 at the platform plate are welded to the embedded steel plate 25 at the platform plate. The anchor bars 26 at the platform plate are spaced 80 mm apart, with three bars in each row. The width of the embedded steel plate 25 at the platform plate is consistent with that of the platform plate 20. The embedded steel plate 25 at the platform plate is embedded in the shield segment 27.

[0093] Then, the embedded steel plate of the rail top air duct is manufactured and installed, and the embedded steel plate 23 of the rail top air duct with a thickness of 16 mm is processed to adapt to the shape and structure of the shield segment 27;

[0094] Then, the φ12 rail top air duct anchor bars 24 are welded to the rail top air duct embedded steel plate 23, the rail top air duct anchor bars 24 are spaced 80 mm apart, three in each row, the width of the rail top air duct embedded steel plate 23 is consistent with the width of the rail top air duct 19, and the rail top air duct embedded steel plate 23 is embedded in the shield segment 27;

[0095] Finally, the shield machine is advanced and the shield segments 27 are assembled. After the construction is completed, they are hoisted out from the receiving shaft 16 of the upward line L2.

[0096] In step B, the construction of the new line 2 down line L2' is as follows:

[0097] First, the large shield machine was transferred to the starting shaft 17 of the down line L2' and hoisted in;

[0098] Then, the pre-buried steel plate of the platform plate is manufactured and installed, and the pre-buried steel plate 25 of the platform plate with a thickness of 16 mm is processed to adapt to the shape and structure of the shield segment 27;

[0099] Then, the φ12 anchor bars 26 at the platform plate are welded to the embedded steel plate 25 at the platform plate. The anchor bars 26 at the platform plate are spaced 80 mm apart, with three bars in each row. The width of the embedded steel plate 25 at the platform plate is consistent with that of the platform plate 20. The embedded steel plate 25 at the platform plate is embedded in the shield segment 27.

[0100] Then, the embedded steel plate of the rail top air duct is manufactured and installed, and the embedded steel plate 23 of the rail top air duct with a thickness of 16 mm is processed to adapt to the shape and structure of the shield segment 27;

[0101] Then, the φ12 rail top air duct anchor bars 24 are welded to the rail top air duct embedded steel plate 23, the rail top air duct anchor bars 24 are spaced 80 mm apart, three in each row, the width of the rail top air duct embedded steel plate 23 is consistent with the width of the rail top air duct 19, and the rail top air duct embedded steel plate 23 is embedded in the shield segment 27;

[0102] Finally, the shield machine is advanced and the shield segments 27 are assembled. After the construction is completed, they are hoisted out from the receiving shaft 18 of the down line L2 ′, and the excavation of the shield tunnel 5 is completed.

[0103] Specifically, a station structure is set up in the shield tunnel 5 along the direction of the existing line section, and the station structure is connected to the shield tunnel to form a subway station perpendicular to the existing line section; transfer passages are set up at both ends of the station structure, and the transfer passages are connected to the platform of the existing line section to realize the transfer function.

[0104] Specifically, step C is to construct the platform slab in the tunnel, and the specific process is as follows:

[0105] First, the lower surface of the platform plate 20 is cleaned, and the steel bars in the platform plate 20 are welded to the steel plate 25 of the pipe segment;

[0106] Then, the platform slab formwork is installed and concrete is poured to complete the construction of the platform slab 20;

[0107] Finally, the track layer 21 is backfilled and the driving track is installed.

[0108] Specifically, step D is to construct the rail top air duct in the tunnel, and the specific process is as follows:

[0109] First, the rail top air duct 19 bracket is erected, and the steel bars in the rail top air duct are welded to the embedded steel plate 23 at the rail top air duct;

[0110] Then, install the duct bottom plate formwork and pour the bottom plate concrete;

[0111] Then, install the suspended wall formwork and pour the suspended wall concrete;

[0112] Finally, the construction of the rail top air duct 19 is completed.

[0113] Specifically, step E excavates a pipe-jacking tunnel to connect the station hall level. The specific process is as follows:

[0114] First, the jacking method is used to construct the jacking tunnel 4 at the station hall level. When constructing the jacking tunnel 4, a construction well is dug at a predetermined station hall level position as the starting point and end point of the jacking machine;

[0115] Then, the pipe jacking machine is installed in the construction pit, and it needs to be precisely aligned to ensure that the jacking path meets the design requirements. The prefabricated pipe segments or frame structures are started to be jacked, assembled section by section, to form the main body of the tunnel;

[0116] Then, during the jacking process, the precise docking of each section and the stability of the structure must be ensured, and the concourse-level tunnel connecting the two ends of the station is gradually formed by jacking the pipe segments;

[0117] Finally, after reaching the intended end point, the pipe jacking construction is completed to ensure that the tunnel structure is stable and perfectly connected to the rest of the station.

[0118] Yet another embodiment

[0119] The construction method of a subway station structure based on a large shield tunnel passing through an existing line section includes the following steps:

[0120] A. Open-cut construction is carried out at both ends of the station to build the main structure of the station;

[0121] B. Excavation of shield tunnels, construction of the new line 2 up line L2 and the new line 2 down line L2';

[0122] C. Platform plate 20 in the construction tunnel;

[0123] D. Rail top air duct in the construction tunnel 19;

[0124] E. Excavate the jacking tunnel 4 to connect the station concourse level.

[0125] Step A involves open excavation at both ends of the station to construct the main structure of the station. The specific process is as follows:

[0126] First, in the open-cut section of the subway station, the foundation pit is excavated using the open-cut method. The retaining structure is constructed first, and then the multi-layer support structure is set up in sequence as the excavation progresses.

[0127] Then, the main structure of the station is constructed, including the pouring of the station floor, station side walls, station middle plate, and station roof;

[0128] After that, the support structures are dismantled in turn.

[0129] Finally, backfill the soil.

[0130] In step B, the new line 2 up line L2 is constructed, and the specific process is as follows:

[0131] First, construct the starting shaft 15 of the up line L2, the receiving shaft 16 of the up line L2, the starting shaft 17 of the down line L2', and the receiving shaft 18 of the down line L2' at both ends of the shield tunnel section of the subway station;

[0132] Then, holes are drilled in the shield segment 27 . After the drilling is completed, the holes are cleaned, steel bars are inserted into the holes for construction, and reinforcing bar embedding glue is injected and reinforcing bars are embedded to complete the embedding of reinforcing bars on the shield segment 27 .

[0133] Afterwards, the shield machine is advanced and the shield segments 27 are assembled. After the construction is completed, they are hoisted out from the receiving shaft 16 of the upward line L2.

[0134] In step B, the construction of the new line 2 down line L2' is as follows:

[0135] First, the large shield machine was transferred to the starting shaft 17 of the down line L2' and hoisted in;

[0136] Then, holes are drilled in the shield segment 27, and after the drilling is completed, the holes are cleaned, and steel bars are inserted into the holes for construction, and the steel bar embedding glue is injected and the steel bars are embedded, so that the steel bars are embedded on the shield segment 27;

[0137] Afterwards, the shield machine is advanced and the shield segments 27 are assembled. After the construction is completed, they are hoisted out from the receiving shaft 18 of the down line L2 ′, and the excavation of the shield tunnel 5 is completed.

[0138] Specifically, step C is to construct the platform slab in the tunnel, and the specific process is as follows:

[0139] First, the base surface under the platform slab 20 is cleaned, the platform slab reinforcement is manufactured and installed, the reinforcement in the platform slab is welded or mechanically connected to the embedded reinforcement, the platform slab formwork is installed, and concrete is poured to complete the construction of the platform slab 20;

[0140] Then, the track layer 21 is backfilled and the driving track is installed.

[0141] Specifically, step D is to construct the rail top air duct in the tunnel, and the specific process is as follows:

[0142] First, the rail top air duct 19 bracket is erected, the rail top air duct steel bars are manufactured and installed, the steel bars are welded or mechanically connected to the embedded steel bars, and the air duct bottom plate template is installed;

[0143] Then, pour the bottom plate concrete, install the hanging wall formwork, pour the hanging wall concrete, and complete the construction of the rail top air duct 19.

[0144] Specifically, step E excavates a pipe-jacking tunnel to connect the station hall level. The specific process is as follows:

[0145] First, the jacking method is used to construct the jacking tunnel 4 at the station hall level. During the construction of the jacking tunnel 4, a construction well is dug at a predetermined station hall level position as the starting point and end point of the jacking machine;

[0146] Then, the pipe jacking machine is installed in the construction pit, and it needs to be precisely aligned to ensure that the jacking path meets the design requirements. The prefabricated pipe segments or frame structures are started to be jacked, assembled section by section, to form the main body of the tunnel;

[0147] Then, during the jacking process, the precise docking of each section and the stability of the structure must be ensured, and the concourse-level tunnel connecting the two ends of the station is gradually formed by jacking the pipe segments;

[0148] Finally, after reaching the intended end point, the pipe jacking construction is completed to ensure that the tunnel structure is stable and perfectly connected to the rest of the station.

[0149] In the present invention, the platform of the newly built station is located below the existing line. The open-cut station has the characteristics of wide and comfortable space inside the station, but it is obviously not usable on the platform of the section under the operating line. The dark excavation method has a greater risk. In order to maintain the net distance with the existing line, the track burial depth will be increased, which will increase the investment budget. The shield method under the operating section can reduce the disturbance to the surrounding soil layer, but the construction of the platform is limited by the size. The space is cramped, and the risk of opening holes in the shield segment is high, and the project is more restricted. In this case, the present invention makes full use of the advantages of the two construction methods of open-cut construction of the station and shield construction of the platform, and innovates the method of building an island station, which can not only solve the problem of the platform crossing the operating section, but also realize the efficient and comfortable use of most of the station space, and can also avoid the damage of the shield segment to reduce the project risk. The present invention can greatly improve the utilization of space, is conducive to the realization of mechanized prefabricated construction, can speed up the excavation speed, and does not need to lower the groundwater level during the construction process, has little disturbance to the surrounding environment and the existing line, and has a low cost.

Claims

1. The subway station structure based on a large shield tunnel passing through the existing line section includes a first underground station hall layer, a second underground equipment layer, a third underground platform layer, an existing line 1, a new line 2, and a long-term planned transfer line 3, which is characterized by: The newly built Line 2 passes under the existing Line 1, and the newly built Line 2 is perpendicular or obliquely intersected with the long-term planned transfer Line 3. The underground first floor station hall layer, the underground second floor equipment layer, and the underground third floor platform layer are arranged vertically.

2. The subway station structure based on a large shield tunneling under an existing line section according to claim 1 is characterized by: The underground first floor station hall layer includes a station hall public area and equipment management room areas at both ends of the underground first floor. The station hall public area includes a left station hall space (9) and a right station hall space (10). A top pipe tunnel (4) is formed between the left station hall space (9) and the right station hall space (10) to connect the two.

3. The subway station structure based on a large shield tunneling under an existing line section according to claim 2 is characterized by: The pipe-jacking tunnel (4) crosses over the existing line 1, and the left station hall space (9) is larger than the right station hall space (10).

4. The subway station structure based on a large shield tunneling under an existing line section according to claim 2 is characterized by: A transfer hall node (6) is provided at the intersection of the right side station hall space (10) and the long-term planned transfer line three.

5. The subway station structure based on a large shield tunneling under an existing line section according to claim 1 is characterized by: The second underground equipment layer includes a second underground equipment management room area, and the second underground equipment management room area includes a left equipment space (11) and a right equipment space (12), and the left equipment space (11) and the right equipment space (12) are separated by an existing line.

6. The subway station structure based on a large shield tunneling under an existing line section according to claim 1 is characterized by: The underground three-story platform layer includes a middle public area and equipment management room areas at both ends of the underground three-story platform layer. The shield tunnel (5) of the underground three-story platform layer passes under the existing line 1. The underground three-story platform layer includes a left platform space (13) and a right platform space (14).

7. A construction method for a subway station structure based on a large shield tunneling under an existing line section, characterized in that: The following steps are involved: A. Open-cut construction is carried out at both ends of the station to build the main structure of the station; B. Excavation of shield tunnels, construction of the new line 2 up line L2 and the new line 2 down line L2'; C. Platform plate (20) in the construction tunnel; D. Rail top air duct in the construction tunnel (19); E. Excavate a pipe-jacking tunnel (4) to connect the station concourse level.

8. The construction method of a subway station structure based on a large shield tunneling under an existing line section according to claim 1 is characterized in that: Step A involves open excavation at both ends of the station to construct the main structure of the station. The specific process is as follows: First, in the open-cut section of the subway station, the foundation pit is excavated using the open-cut method. The retaining structure is constructed first, and then the multi-layer support structure is set up in sequence as the excavation progresses. Then, the main structure of the station is constructed, including the pouring of the station floor, station side walls, station middle plate, and station roof; After that, the support structures are dismantled in turn. Finally, backfill the soil.

9. The construction method of a subway station structure based on a large shield tunneling under an existing line section according to claim 1, characterized in that: In step B, the new line 2 up line L2 is constructed, and the specific process is as follows: First, the starting shaft (15) of the up line L2, the receiving shaft (16) of the up line L2, the starting shaft (17) of the down line L2', and the receiving shaft (18) of the down line L2' are constructed at both ends of the shield tunnel section of the subway station. Then, a shield segment (27) with a steel plate or a shield segment (27) with embedded reinforcement is constructed; Finally, the large shield is hoisted in from the starting shaft (15) of the upward line L2, the shield is advanced and the shield segments (27) are assembled; after the construction is completed, it is hoisted out from the receiving shaft (16) of the upward line L2.

10. The construction method of a subway station structure based on a large shield tunneling under an existing line section according to claim 9, characterized in that: In step B, the construction of the new line 2 down line L2' is as follows: First, the large shield machine is transferred to the starting shaft (17) of the downlink line L2' and hoisted in; Then, a shield segment (27) with a steel plate or a shield segment (27) with embedded reinforcement is constructed; Finally, the shield machine is advanced and the shield segments (27) are assembled. After the construction is completed, they are hoisted out from the receiving shaft (18) of the down line L2', completing the excavation of the shield tunnel (5).

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