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

Abstract

The utility model discloses a subway station structure based on a large shield underneath passing existing line section, which 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 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. According to the utility model, the minimum influence on the existing line is realized, the continuous and stable operation of the existing line is ensured, the construction speed is obviously improved, and the engineering period is effectively shortened. In addition, the distance between the newly-built station and the existing line interval structure is greatly reduced, the structural burial depth of the portion, not underneath passing through the existing line, of the station is reduced, engineering risks are reduced, and investment cost is remarkably saved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of rail transit construction, and particularly relates to a subway station structure based on large shield underpassing existing line section. BACKGROUND

[0002] With the rapid expansion and interlacing of domestic rail transit network, the construction of new lines is facing unprecedented challenges: the design complexity is increasing sharply, the construction risk is rising sharply, especially under the background of accelerating urbanization, the unbalanced urban development and the high cost of reserved space make it difficult to effectively predict and reserve the future expansion conditions of the existing lines. In order to pursue efficient transfer, the new line station often needs to cross the existing operation section layout, which puts forward double requirements for ensuring the stability of the new line structure and the safety of the existing line operation.

[0003] At present, although the mine method and the shield method are applied in the construction of new section under the existing station, the construction method for directly underpassing the existing line section of the new station is still scarce. In view of the variability of geological conditions, the consideration of tunnel bearing capacity and the strict requirement of vibration control, such construction is easy to disturb the stability of the existing line structure, especially in the complex geological area, the risk, difficulty and cost are significantly increased. Although the shield method is the preferred method due to its technical advantages, it is limited in station construction - the size of the shield limits the arrangement of passenger service facilities (such as building escalators), equipment rooms and other facilities, and the shield segment opening technology is difficult and high-risk, and simply relying on the shield method to implement underpassing construction is not enough.

[0004] Therefore, it is particularly important to develop an innovative construction method to safely and efficiently underpass and construct a subway station under the existing operation line section without reserved station crossing conditions. SUMMARY

[0005] The utility model discloses a subway station structure based on large shield underpassing existing line section, which is proposed to solve the problems in the prior art.

[0006] The technical scheme of the utility model is: a subway station structure based on large shield underpassing existing line section, which comprises 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 planning transfer line three, the newly-built line two underpasses the existing line one, the newly-built line two is perpendicular or oblique to the long-term planning 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 vertically arranged.

[0007] Further, the underground first floor station hall layer comprises a station hall public area and underground first floor two-end equipment management house area, the station hall public area comprises a left station hall space and a right station hall space, and a top pipe tunnel connecting the left station hall space and the right station hall space is formed.

[0008] Further, the top pipe tunnel is above the existing line one, and the left station hall space is larger than the right station hall space.

[0009] Further, the right station hall space is provided with a transfer station hall node at the intersection with the long-term planning transfer line three.

[0010] Further, the underground second floor equipment layer comprises an underground second floor equipment management house area, and the underground second floor equipment management house area comprises a left equipment space and a right equipment space, and the left equipment space and the right equipment space are separated by the existing line one.

[0011] Further, the underground third floor station layer comprises an intermediate public area and underground third floor two-end equipment management house area, the shield tunnel of the underground third floor station layer is under the existing line one, and the underground third floor station layer comprises a left station space and a right station space.

[0012] Further, the shield tunnel strives for shorter distance transfer, and should be within a safety distance range on both sides of the existing line one, the safety distance range refers to that the working point distance between the two groups of building escalators on the station platform layer is less than 100 meters, so that the risk of breaking the shield segment due to the increase of evacuation facilities in the shield tunnel can be avoided.

[0013] The utility model has the advantages of the following:

[0014] The utility model realizes the minimum influence on the existing line, ensures the continuous and stable operation of the existing line, significantly improves the construction speed, effectively shortens the engineering period, and further, the utility model greatly reduces the distance between the newly-built station and the existing line interval structure, and reduces the structure burial depth of the part of the station not passing under the existing line, not only reduces the engineering risk, but also realizes the significant saving of investment cost.

[0015] The utility model overcomes the space limitation of the newly-built station, optimizes the passenger flow line design, can not only solve the problem that the platform passes through the existing line interval, but also realize efficient and comfortable use of most of the space of the newly-built station, and further, can avoid the shield segment damage to reduce the engineering risk, and provides a wider thinking and selection space for the design of the newly-built station of the urban rail transit line.

[0016] The utility model integrates the quintessence of many kinds of craft of open cut method, pipe jacking method, shield method etc, forms a set of comprehensive solution, provides strong technical support for future new station crossing existing line section, greatly enhances the flexibility and adaptability of track traffic construction, lays a solid foundation for the sustainable development of urban track traffic. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is the station underground one layer plane arrangement drawing in the utility model;

[0018] Figure 2 It is the station underground two layer plane arrangement drawing in the utility model;

[0019] Figure 3 It is the station underground three layer plane arrangement drawing in the utility model;

[0020] Figure 4 It is the station longitudinal section view in the utility model;

[0021] Figure 5 It is the station transverse section view in the utility model;

[0022] Figure 6 It is the shield tunnel plane view of underpassing existing line section in the utility model;

[0023] Figure 7 It is the shield tunnel cross section view in the utility model;

[0024] Figure 8 It is the preburied steel plate and anchor reinforcement annular arrangement drawing in the utility model;

[0025] Figure 9 It is the segment preburied steel plate and anchor reinforcement schematic view in the utility model;

[0026] Among them:

[0027] L1 existing line one up line section L1' existing line one down line section

[0028] L2 new line two up line L2' new line two down line

[0029] L3 long-term planning transfer line three up line

[0030] L3' long-term planning transfer line three down line

[0031] 4 pipe jacking tunnel 5 shield tunnel

[0032] 6 transfer station hall node 7 left new station main body

[0033] 8 right new station main body 9 left station hall space

[0034] 10 Right-side station hall space; 11 Left-side equipment space

[0035] 12 Right-side equipment space 13 Left-side platform space

[0036] 14 Right-side platform space 15 Upbound Line L2 Starting Shaft

[0037] 16 Uplink L2 receiving well; 17 Downlink L2' launching well

[0038] 18 Downlink L2' Receiving Shaft 19 Rail Top Ventilation Duct

[0039] 20 Platform slabs, 21 Track levels

[0040] 22. Outline of the train; 23. Embedded steel plate at the top of the rail ventilation duct.

[0041] 24 Anchor bars at the top ventilation duct of the rail; 25 Embedded steel plates at the platform slab.

[0042] 26 Anchor bars at the platform slab; 27 Shield tunnel segments. Detailed Implementation

[0043] The present invention will now be described in detail with reference to the accompanying drawings and embodiments:

[0044] like Figures 1 to 9 As shown, the subway station structure based on the large shield tunnel passing under the existing line section includes an underground concourse level, an underground equipment level, an underground platform level, an existing line 1, a newly built line 2, and a planned transfer line 3 in the future. The newly built line 2 passes under the existing line 1, and the newly built line 2 is perpendicular or oblique to the planned transfer line 3 in the future. The subway station structure of the newly built line 2 includes the main station body 7 on the left side and the main station body 8 on the right side of the existing line 1. The underground concourse level, the underground equipment level, and the underground platform level are arranged vertically.

[0045] The underground station hall includes a public area and equipment management rooms at both ends of the underground level. The public area includes a left station hall space 9 and a right station hall space 10. A pipe jacking tunnel 4 connects the left station hall space 9 and the right station hall space 10.

[0046] The pipe jacking tunnel 4 crosses over the existing railway line 1, and the left-side station hall space 9 is larger than the right-side station hall space 10.

[0047] A transfer station hall node 6 is set at the intersection of the right-side station hall space 10 and the planned transfer line 3 in the future.

[0048] The underground two-layer equipment layer includes an underground two-layer equipment management room area, and the underground two-layer equipment management room area includes a left equipment space 11 and a right equipment space 12, which are separated by the existing line one.

[0049] The underground three-layer platform layer includes a middle public area and underground three-layer equipment management room areas at both ends of the platform layer, and the underground three-layer platform layer passes through the existing line one below the shield tunnel 5, and includes a left platform space 13 and a right platform space 14.

[0050] Specifically, the existing line one includes an existing line one up-line section L1 and an existing line one down-line section L1', and the existing line one up-line section L1 and the existing line one down-line section L1' are arranged in the existing underground section tunnel. The pipe jacking tunnel 4 is arranged above the existing underground section tunnel, and the shield tunnel 5 is arranged below the existing underground section tunnel.

[0051] Specifically, the underground one-layer station hall layer is connected by the pipe jacking method to cross the existing line section, and the rectangular pipe jacking tunnel connects the station halls on both sides, and the pipe jacking method affects the station hall building arrangement of the station. When the underground one-layer station hall layer is connected by the pipe jacking, the floor escalator arrangement needs to comprehensively consider the passenger flow organization of the entire station hall to meet the function requirements of entering and exiting the station. When the station hall layer is not connected by the pipe jacking, the station hall layer will be divided into two independent parts.

[0052] Specifically, the underground two-layer equipment layer is arranged below the underground one-layer station hall layer under the premise of saving the scale of the newly-built station main body, and the equipment layer is divided into two independent parts due to the existing line section.

[0053] Specifically, the underground three-layer platform layer connects the main structures of the stations on both sides through the shield shaft. The diameter size of the shield needs to meet the requirements of the internal facilities and equipment of the shield section platform under the limitation of the vertical height, including the side platform, the track area and the space required by the roof equipment pipeline. According to the fireproofing specification requirements, the length of the shield section cannot cause the evacuation distance between the working points of the two groups of floor escalators on the platform layer of the station to exceed 100 m.

[0054] Specifically, the newly-built line two includes a newly-built line two up-line L2 and a newly-built line two down-line L2', and the long-term planning transfer line three includes a long-term planning transfer line three up-line L3 and a long-term planning transfer line three down-line L3'.

[0055] Specifically, the underground one-layer station hall layer includes an interval area of the existing line one in the middle part, and two 8.1m-wide pipe jacking tunnels 4 are arranged to connect a left station hall space 9 and a right station hall space 10. The left station hall space 9 is uniformly provided with three groups of floor escalators, and the right station hall space 10 is provided with one group of double escalators, which meet the function requirements of the recent entering and exiting the station and the long-term transfer.

[0056] Specifically, the underground two-layer equipment layer is a device management housing area. The station device management housing area is divided into two independent spaces, i.e., a left equipment space 11 and a right equipment space 12, due to the existence of the existing line one. The right equipment space 12 reserves a section of the line three interval crossing area. A safe exit is provided near the shield well at the left end of the left equipment space 11 area.

[0057] Specifically, in the underground three-layer platform layer, a shield with a diameter of 8.8 m is used to pass through the existing line one area below the platform. The shield section connecting the underground three-layer platform has a side platform width of 3 m. Four groups of building escalator groups are provided for the effective platform to access the station hall. Three groups of double escalators are provided on the left side of the existing line one interval. One group of double escalators serves the north side of the boarding and alighting passenger flow and the passenger flow of the long-term planned interchange line three.

[0058] There is a vertical elevator near the end wall of the shield section and the open excavation section to access the hall layer. In this way, the station of the newly built line two can be quickly built without affecting the operation of the existing line one. In addition, flexible implementation conditions are reserved for the long-term planning interchange line three, further improving the engineering efficiency and safety, reducing the engineering cost and environmental impact.

[0059] The construction method of the subway station structure based on the large shield underpassing the existing line interval includes the following steps:

[0060] A. Open excavation construction is performed at both ends of the station to build the main structure of the station;

[0061] B. Shield tunnel excavation is performed to construct the newly built line two up line L2 and the newly built line two down line L2';

[0062] C. Construction of the platform slab 20 in the tunnel;

[0063] D. Construction of the track top air duct 19 in the tunnel;

[0064] E. Excavation of the pipe roof tunnel 4 to connect the station hall layer of the station.

[0065] Step A performs open excavation construction at both ends of the station to build the main structure of the station, and the specific process is as follows:

[0066] First, in the open excavation interval of the subway station, the open excavation method is used to excavate the foundation pit. The enclosure structure is constructed first, and the multi-layer support structure is set up in sequence as the excavation progresses;

[0067] Then, the main structure of the station is built, including the pouring of the station floor, the station side wall, the station middle plate, and the station roof;

[0068] Then, the removal of each support structure is performed in sequence;

[0069] Finally, the backfilling is carried out.

[0070] In step B, the newly-built line two up line L2 is constructed, and the specific process is as follows:

[0071] Firstly, the up line L2 starting shaft 15, the up line L2 receiving shaft 16, the down line L2' starting shaft 17 and the down line L2' receiving shaft 18 are respectively constructed at both ends of the shield interval of the subway station;

[0072] Then, the station platform plate embedded steel plate is manufactured and installed, and the station platform plate embedded steel plate 25 with a thickness of 16 mm is processed to adapt to the shape and structure of the shield segment 27;

[0073] Then, the station platform plate anchor reinforcement 26 with a diameter of φ12 is welded to the station platform plate embedded steel plate 25, the station platform plate anchor reinforcement 26 is spaced 80 mm apart, three in each row, the width of the station platform plate embedded steel plate 25 is consistent with the width of the station platform plate 20, and the station platform plate embedded steel plate 25 is embedded into the shield segment 27;

[0074] Then, the rail top air duct embedded steel plate is manufactured and installed, and the rail top air duct embedded steel plate 23 with a thickness of 16 mm is processed to adapt to the shape and structure of the shield segment 27;

[0075] Then, the rail top air duct anchor reinforcement 24 with a diameter of φ12 is welded to the rail top air duct embedded steel plate 23, the rail top air duct anchor reinforcement 24 is 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 into the shield segment 27;

[0076] Finally, the shield is pushed forward and the shield segment 27 is assembled, and after the construction is completed, the shield segment 27 is hoisted out from the up line L2 receiving shaft 16.

[0077] In step B, the newly-built line two down line L2' is constructed, and the specific process is as follows:

[0078] Firstly, the large shield is transferred to the down line L2' starting shaft 17 and hoisted in;

[0079] Then, the station platform plate embedded steel plate is manufactured and installed, and the station platform plate embedded steel plate 25 with a thickness of 16 mm is processed to adapt to the shape and structure of the shield segment 27;

[0080] Then, the station platform plate anchor reinforcement 26 with a diameter of φ12 is welded to the station platform plate embedded steel plate 25, the station platform plate anchor reinforcement 26 is spaced 80 mm apart, three in each row, the width of the station platform plate embedded steel plate 25 is consistent with the width of the station platform plate 20, and the station platform plate embedded steel plate 25 is embedded into the shield segment 27;

[0081] Then, the rail top air duct pre-embedded steel plate is made and installed, the 16mm thick rail top air duct pre-embedded steel plate 23 is processed to adapt to the shape and structure of the shield segment 27;

[0082] Then, the rail top air duct anchor 24 of φ12 is welded to the rail top air duct pre-embedded steel plate 23, the rail top air duct anchor 24 is spaced 80mm apart, three in each row, the width of the rail top air duct pre-embedded steel plate 23 is consistent with the width of the rail top air duct 19, and the rail top air duct pre-embedded steel plate 23 is embedded into the shield segment 27;

[0083] Finally, the shield is advanced and the shield segment 27 is assembled, and after the construction is completed, it is hoisted out of the descending line L2' receiving well 18, and the excavation of the shield tunnel 5 is completed.

[0084] Specifically, the station structure is arranged in the direction of the existing line section in the shield tunnel 5, the station structure is connected with the shield tunnel to form a subway station perpendicular to the existing line section, and the transfer channels are arranged at both ends of the station structure and connected with the platforms of the existing line section to realize the transfer function.

[0085] Specifically, the step C constructs the platform plate in the tunnel, and the specific process is as follows:

[0086] First, the lower base 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 segment;

[0087] Then, the platform plate formwork is installed, and the concrete is poured to complete the construction of the platform plate 20;

[0088] Finally, the track layer 21 is backfilled, and the running track is installed.

[0089] Specifically, the step D constructs the rail top air duct in the tunnel, and the specific process is as follows:

[0090] First, the rail top air duct 19 support is erected, and the steel bars in the rail top air duct are welded to the rail top air duct pre-embedded steel plate 23;

[0091] Then, the air duct bottom plate formwork is installed, and the bottom plate concrete is poured;

[0092] Then, the hanging wall formwork is installed, and the hanging wall concrete is poured;

[0093] Finally, the construction of the rail top air duct 19 is completed.

[0094] Specifically, the step E excavates the top pipe tunnel to connect the station hall layer, and the specific process is as follows:

[0095] First, the station hall layer top pipe tunnel 4 is constructed by using the pipe jacking method, and a construction well is excavated at the predetermined station hall layer position as the starting point and the end point of the pipe jacking machine during the construction of the top pipe tunnel 4;

[0096] Then, install the pipe jacking machine in the construction well, which needs to be accurately aligned to ensure that the jacking path meets the design requirements. Start jacking the prefabricated segments or frame structures, assemble them section by section to form the main body of the tunnel;

[0097] Then, during the jacking process, it is necessary to ensure the accurate docking of each segment and the stability of the structure, and gradually form the station hall layer tunnel connecting the two ends of the station by jacking the segments;

[0098] Finally, after reaching the predetermined end point, the pipe jacking construction is completed, ensuring that the tunnel structure is stable and perfectly connected with other parts of the station. Embodiment

[0099] The construction method of the subway station structure based on the large shield underpassing the existing line section includes the following steps:

[0100] A. Open excavation construction is carried out at both ends of the station to build the main structure of the station;

[0101] B. Shield tunnel excavation, construction of the newly built line two up line L2, the newly built line two down line L2';

[0102] C. Construction of the platform slab 20 in the tunnel;

[0103] D. Construction of the track top air duct 19 in the tunnel;

[0104] E. Excavate the pipe jacking tunnel 4 to connect the station hall layer.

[0105] Step A carries out open excavation construction at both ends of the station to build the main structure of the station, the specific process is as follows:

[0106] First, in the open excavation section of the subway station, the foundation pit is excavated by using the open excavation method, and the enclosure structure construction is carried out first, and then the multi-layer support structure is set up in sequence with the excavation;

[0107] Then, the construction of the main structure of the station is carried out, including the pouring of the station floor, the station side wall, the station middle plate and the station roof;

[0108] Then, the removal work of each support structure is carried out in sequence;

[0109] Finally, the earth covering backfilling is carried out.

[0110] The specific process of constructing the newly built line two up line L2 in step B is as follows:

[0111] First, the up line L2 starting well 15, the up line L2 receiving well 16, the down line L2' starting well 17 and the down line L2' receiving well 18 are constructed at both ends of the subway station shield section respectively;

[0112] Then, holes are drilled in the shield segment 27, the holes are cleaned after the drilling is completed, steel bars are inserted into the holes for construction, anchoring glue is injected and the steel bars are anchored, and the anchoring of the steel bars on the shield segment 27 is completed.

[0113] Then, the shield is advanced and the shield segment 27 is assembled, and after the construction is completed, the shield is hoisted out by the up-line L2 receiving shaft 16.

[0114] In step B, the newly-built down-line L2' is constructed, and the specific process is as follows:

[0115] First, the large shield is transferred to the down-line L2' starting shaft 17 and is hoisted in;

[0116] Then, holes are drilled in the shield segment 27, the holes are cleaned after the drilling is completed, steel bars are inserted into the holes for construction, anchoring glue is injected and the steel bars are anchored, and the anchoring of the steel bars on the shield segment 27 is completed.

[0117] Then, the shield is advanced and the shield segment 27 is assembled, and after the construction is completed, the shield is hoisted out by the down-line L2' receiving shaft 18, and the excavation of the shield tunnel 5 is completed.

[0118] Specifically, in step C, the platform plate in the tunnel is constructed, and the specific process is as follows:

[0119] First, the platform plate 20 lower surface is cleaned, the platform plate steel bars are made and installed, the platform plate steel bars are welded or mechanically connected with the anchored steel bars, the platform plate formwork is installed, and the concrete is poured to complete the construction of the platform plate 20.

[0120] Then, the track layer 21 is backfilled, and the running track is installed.

[0121] Specifically, in step D, the track top air duct in the tunnel is constructed, and the specific process is as follows:

[0122] First, the track top air duct 19 support is erected, the track top air duct steel bars are made and installed, the steel bars are welded or mechanically connected with the anchored steel bars, and the air duct bottom plate formwork is installed.

[0123] Then, the bottom plate concrete is poured, the hanging wall formwork is installed, the hanging wall concrete is poured, and the construction of the track top air duct 19 is completed.

[0124] Specifically, in step E, the top pipe tunnel is excavated to connect the station hall layer, and the specific process is as follows:

[0125] First, the station hall layer top pipe tunnel 4 is constructed by using the pipe jacking method, and a construction shaft is excavated at a predetermined station hall layer position as the starting point and the ending point of the pipe jacking machine during the construction of the top pipe tunnel 4.

[0126] Then, install the pipe jacking machine in the construction well, which needs to be accurately aligned to ensure that the jacking path meets the design requirements. Start jacking the prefabricated segments or frame structures, assemble them section by section to form the main body of the tunnel;

[0127] Then, during the jacking process, it is necessary to ensure the accurate docking of each segment and the stability of the structure, and gradually form the station hall layer tunnel connecting the two ends of the station by jacking the segments;

[0128] Finally, after reaching the predetermined end point, the pipe jacking construction is completed, ensuring that the tunnel structure is stable and perfectly connected with other parts of the station.

[0129] In the utility model, the newly built station platform is located below the existing line, and the open cut method station has the characteristics of spacious and comfortable station space, but it is obviously not suitable for use on the platform under the operating line interval. The risk of the underground excavation method is larger, and in order to maintain the clear distance from the existing line, the track buried depth is also increased, and the investment budget is increased. The shield method under the operating interval can reduce the disturbance to the surrounding soil layer, but the space is limited due to the size limitation of the station platform, and the shield segment opening risk is high, and the engineering is limited. Under this condition, the utility model makes full use of the advantages of the open cut method station construction and the shield method station platform construction, innovates the method of building island type station, which can not only solve the problem of platform crossing the operating interval, but also realize the efficient and comfortable use of most of the station space, and avoid the damage of shield segment to reduce the engineering risk. The utility model can greatly improve the space utilization, is conducive to realizing the mechanized assembly type construction, can speed up the tunneling speed, and does not need to lower the underground water level in the construction process, has small disturbance to the surrounding environment and the existing line, and has low cost.

Claims

1. A subway station structure based on a large shield underpassing an existing line section, comprising 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 planning transfer line three, characterized in that: The new line two underpasses the existing line one, the new line two is perpendicular or oblique to the long-term planning transfer line three, the underground first floor station hall layer, the underground second floor equipment layer and the underground third floor platform layer are vertically arranged.

2. The subway station structure based on a large shield underpassing an existing line section according to claim 1, characterized in that: The underground first floor station hall layer comprises a station hall public area and an underground first floor equipment management house area at both ends, the station hall public area comprises a left station hall space (9) and a right station hall space (10), and 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 spaces.

3. The subway station structure based on a large shield underpassing an existing line section according to claim 2, characterized in that: The pipe jacking tunnel (4) overlies the existing line one, 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 underpassing an existing line section according to claim 2, characterized in that: A transfer station hall node (6) is arranged at the intersection of the right station hall space (10) and the long-term planning transfer line three.

5. The subway station structure based on a large shield underpassing an existing line section according to claim 1, characterized in that: The underground second floor equipment layer comprises an underground second floor equipment management house area, and the underground second floor equipment management house area comprises a left equipment space (11) and a right equipment space (12), which are separated by the existing line one.

6. The subway station structure based on a large shield underpassing an existing line section according to claim 1, characterized in that: The underground third floor platform layer comprises a middle public area and an underground third floor equipment management house area at both ends, a shield tunnel (5) of the underground third floor platform layer underpasses the existing line one, and the underground third floor platform layer comprises a left platform space (13) and a right platform space (14).

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