Subway separation island type underground excavation station construction method

Abstract

The invention discloses a subway separation island type underground excavation station construction method. The method comprises the following steps that a vertical shaft is excavated, and a construction transverse channel connected with a pilot tunnel is excavated; pilot tunnels are constructed and supported; constructing an enclosure structure and a waterproof curtain, and constructing a top beam on the pile; an advance support and a primary support are constructed, and large arch earthwork is excavated; pouring an arch secondary lining structure; pouring the side wall and the middle plate; constructing a structural bottom plate and side walls; constructing a contact channel; and a platform plate and a rail top air duct are constructed. The method has the advantages of being safe and reliable in construction process, low in economic cost, small in environmental influence, good in passenger use attribute, high in underground space utilization rate, convenient to connect with surrounding traffic and urban space and the like, and has wide popularization prospects.

Description

Technical Field

[0001] The invention belongs to the technical field of station dark excavation construction, in particular to a subway separated island type dark excavation station construction method. Background Art

[0002] In order to meet the needs of citizens for convenient travel, subway stations are often set up in urban areas with heavy traffic, and often need to be built under existing elevated roads. However, due to the limitation of the width of the existing road, it is inevitable to set up the main body of the subway station under the existing bridge. Due to the clearance limit under the bridge, the existing bridge needs to be demolished when using the open-cut method. The overall station main structure excavated by the standard PBA method will also conflict with the existing bridge piles. Therefore, it is particularly necessary to seek a construction method that can fully utilize the narrow space on both sides of the pile foundation under the road and protect the bridge piles. Summary of the invention

[0003] In view of the above-mentioned problems, the present invention proposes a construction method for a subway separated island type dark excavation station.

[0004] A method for constructing a subway separated island type dark excavation station comprises the following steps: Step S1: excavating a vertical shaft and a construction transverse passage connecting the pilot tunnel; Avoid the existing bridge pile foundation, dig the vertical shaft and support it, and dig the cross passage on both sides of the bridge pile foundation; Step S2: constructing a pilot tunnel and providing support; Construct the advance support structure of the arch of pilot tunnel 5, reinforce the stratum by grouting, excavate the earthwork in the pilot tunnel by the step method, and provide support; Step S3: construct bored cast-in-place piles, water-stop curtains, and cap beams on the piles; Construct bored cast-in-place piles and water-stop curtains in the pilot tunnel, remove the pile heads and construct cap beams on the piles; Step S4: performing main body advance support and main body initial support, and excavating earthwork of the large arch; Construct a large pipe shed for the large arch, inject grouting to pre-reinforce the stratum of the large arch, excavate the earthwork of the large arch, construct the initial support of the main body, and strengthen monitoring and measurement; Step S5: pouring the secondary lining structure of the large arch; After the space under the arch is connected, the secondary lining structure is constructed, the guide tunnel support is removed, the waterproof board of the arch is laid, and the secondary lining structure of the arch is poured. During the construction process, monitoring and measurement are strengthened; Step S6: pouring side walls and middle plates; Continue to dig downwards, apply sprayed concrete and waterproof panels between the retaining piles, use the soil at the bottom of the pit to set up formwork supports, and cast the side walls and middle plates; Step S7: constructing the structural base plate and side walls; After excavating to the bottom of the pit, quickly construct the bottom cushion of the structure, lay the waterproof layer, and construct the bottom plate and side walls of the structure; Step S8: constructing a communication channel; A communication passage connecting the two separate station halls and platforms is excavated between the bridge pile foundations and the lining structure is constructed; Step S9: constructing the platform plate and the rail top air duct; The platform slab, supporting walls and track-top air ducts are constructed to complete the main construction.

[0005] Preferably, in step S1, the transverse passage is constructed by opening a horse head door in the vertical shaft, and the guide tunnel is constructed by opening a horse head door in the transverse passage.

[0006] Preferably, in step S2, the initial support of the guide tunnel adopts grid support, and a grid node plate of the large arch portion is reserved on the grid.

[0007] Further preferably, in step S4, the main body initial support adopts a large arch initial support grid, the foot of the grid is connected to the embedded steel bars on the crown beam, and the upper part of the grid is connected to the grid node plate reserved in the guide tunnel.

[0008] Further preferably, when the large arch portion is excavated, the excavation step distance is equal to the spacing of the initial support grids of the large arch.

[0009] Preferably, in step S3, the water-stop curtain is an ultra-high pressure jet mixing pile.

[0010] Preferably, in step S4, the main body advance support adopts a large pipe rack and deep hole grouting support for the large arch.

[0011] Preferably, in step S5, the secondary lining structure is constructed from the middle position of the two transverse passages backwards in the direction of the transverse passages, and the guide tunnel support is dismantled in sections along the longitudinal direction of the station.

[0012] Preferably, in step S6, the side wall and the middle plate are cast at one time, and steel bars for the rail top air duct are reserved on the middle plate 11.

[0013] Preferably, in step S8, a communication passage connecting the hall layer and the platform layer is set between the separated hall and the platform, and the communication passage is constructed by the CRD method.

[0014] The beneficial effects of the present invention are: (1) By dividing the main body of the station into two parts and setting it up close to the existing road bridge piles, the utilization rate of the underground space is fully improved, the impact on the surrounding plots is reduced, and the overall development benefits of the node city are significant; the split station adopts the dark excavation method for construction, which not only effectively protects the safety of side bridge piles, underground pipelines and other structures, but also does not affect ground traffic. The project has high safety, low environmental impact, and obvious social benefits.

[0015] (2) The platform level and the concourse level of the split station are quickly connected through connecting passages that avoid bridge piles. The platform level connects the separated platforms through multiple connecting passages to form an integrated island platform. The platform has a large overall space, can accommodate a large number of passengers, has a high utilization rate, and has a good effect in dispersing the flow of people. It is relatively centralized and convenient to manage, and it is convenient for passengers to turn back during the journey. Passengers at the concourse level can quickly enter the concourse above the left and right lines through the middle connecting passage, and then quickly pass through all entrances and exits and property development entrances to quickly enter the ground and underground spaces on both sides of the road. The overall functionality of the station is strong, which is convenient for the connection between the subway and surrounding transportation and is conducive to the development of urban TOD.

[0016] (3) There are no columns in the middle of the left-right line split station. It is a single-span column-free large space structure, which provides a good visual effect for passengers. The arched space on the concourse floor is high and has a large span, providing a wide space for decoration creativity and a large space for urban culture to be displayed.

[0017] (4) The structure and construction method described in the present invention have the advantages of safe and reliable construction process, low economic cost, small environmental impact, good passenger usability, high underground space utilization rate, and convenient connection with surrounding transportation and urban space, and have broad prospects for promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The technical solution of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments, but it should be understood that these drawings are designed only for explanation purposes and are not intended to limit the scope of the present invention. In addition, unless otherwise specified, these drawings are intended only to conceptually illustrate the structural configurations described herein and are not necessarily drawn to scale.

[0019] Figure 1 This is a schematic diagram of the station and bridge pile locations; Figure 2 It is the structure of some construction steps Figure 1 ; Figure 3 It is the structure of some construction steps Figure 2 ; Figure 4 It is the structure of some construction steps Figure 3 ; Figure 5 It is a cross-sectional view of the subject; Figure 6 It is a plan view of the platform level; Figure 7 This is a schematic diagram of the station hall level; Figure 8 It is a flow chart of the construction method of the present invention.

[0020] In the figure: 1-station; 2-cap beam; 3-bridge pile foundation; 4-bridge; 5-pilot tunnel; 6-retaining pile foundation; 7-platform; 8-a earthwork; 9-b earthwork; 10-large arch; 11-middle plate; 12-structural bottom plate; 13-ultra-high pressure jet mixing piles; 14-track surface; 15-platform layer; 16-platform plate; 17-station hall layer; 18-entrance and exit; 19-communication passage; 20-track top air duct; 21-side wall; 22-secondary lining structure. DETAILED DESCRIPTION

[0021] First of all, it should be noted that the specific structure, features and advantages of the present invention will be specifically described below by way of example, but all descriptions are only for illustration and should not be understood as limiting the present invention. In addition, any single technical feature described or implied in the embodiments mentioned herein, or any single technical feature displayed or implied in the drawings, can still be combined or deleted between these technical features (or their equivalents) to obtain more other embodiments of the present invention that may not be directly mentioned in this document. In addition, in order to simplify the drawings, the same or similar technical features may be marked only in one place in the same drawing.

[0022] In the present invention, unless otherwise clearly stipulated and limited, the terms such as "installation", "setting", "connection", "fixation" and "screw-on" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, ordinary technicians in this field can understand the specific meanings of the above terms in the present invention according to the specific circumstances.

[0023] The following is combined with Figure 1 -Attached Figure 8 The present invention will be described in detail. Example 1

[0024] A method for constructing a subway separated island type dark excavation station comprises the following steps: Step S1: excavating a vertical shaft and a construction transverse passage connecting the pilot tunnel; Avoid the existing bridge pile foundation 3, dig a vertical shaft and support it, and dig a cross passage on both sides of the bridge pile foundation 3; Step S2: constructing a pilot tunnel 5 and providing support; Construct the advance support structure of the arch of the pilot tunnel 5, and reinforce the stratum by grouting. Use the step method to excavate the earthwork in the pilot tunnel 5 and provide support. Step S3: construct bored cast-in-place piles, water-stop curtains, and cap beams 2 on the piles; Construct bored cast-in-place piles and water-stop curtains in the pilot tunnel 5, remove the pile heads and construct cap beams 2 on the piles; Step S4: performing main body advance support and main body initial support, and excavating earthwork of the large arch; Construct a large pipe shed for the large arch, inject grouting to pre-reinforce the stratum of the large arch, excavate the earthwork of the large arch, construct the initial support of the main body, and strengthen monitoring and measurement; Step S5: Casting the secondary lining structure 22 of the large arch portion 10; After the space below the large arch 10 is connected, the secondary lining structure 22 is constructed, the guide hole 5 support is removed, the waterproof board of the large arch 10 is laid, and the secondary lining structure 22 of the large arch 10 is cast. During the construction process, monitoring and measurement are strengthened; Step S6: pouring the side wall 21 and the middle plate 11; Continue to dig downwards, construct 6 retaining pile foundations with sprayed concrete and waterproof panels, use the soil at the bottom of the pit to set up formwork supports, and cast the side walls 21 and the middle plate 11; Step S7: constructing the structural base plate 12 and the side wall 21; After excavating to the bottom of the pit, quickly construct the bottom cushion of the structure, lay the waterproof layer, and construct the bottom plate 12 and side wall 21 of the structure; Step S8: constructing the communication channel 19; A communication passage 19 connecting the two separate station halls and platforms is excavated between the bridge pile foundations 3 and a lining structure is constructed; Step S9: constructing the platform plate 16 and the rail top air duct 20; The platform slab 16, supporting wall and track top air duct 20 are constructed to complete the main construction.

[0025] Working principle: The present invention is based on the traditional dark excavation method, avoids the existing bridge pile foundation 3, separates the left and right lines of the station body into separate station halls and platforms arranged adjacent to the bridge pile foundation 3, and connects them through a communication channel 19 to form a whole.

[0026] The construction steps are as follows: construct the vertical shaft, the horizontal passage and the guide tunnel 5; construct the initial support of the large arch 10; cast the secondary lining structure 22 of the large arch 10; cast the side wall 21 and the middle plate 11; cast the side wall 21, construct the structural bottom plate 12 and the side wall 21; construct the communication passage; construct the platform plate 16, the supporting wall and the track top air duct 20, and complete the main construction.

[0027] Compared with the traditional open-cut construction method, this construction method can excavate the station 1 which is generally difficult to excavate under the low-clearance bridge and close to both sides of the bridge pile foundation 3; Compared with the traditional dark-excavated island station, this construction method can be used to construct a column-free separated island station with a larger single arch span; Compared with the side-type station, this method cleverly connects the separated platforms into an integrated island platform 7 through multiple connecting passages. The platform utilization rate is high, the effect of dispersing the flow of people is good, the management is relatively centralized and convenient, and it is convenient for passengers to turn back during the journey.

[0028] Furthermore, it can also be considered in the embodiment that in the step S1, the transverse passage is constructed by opening a horse head door in the vertical shaft, and the guide tunnel 5 is constructed by opening a horse head door in the transverse passage.

[0029] In this embodiment, the bridge pile foundation 3 does not need to be removed when the shaft is excavated, and the guide tunnel 5 is arranged close to the existing bridge pile foundation 3 , and the guide tunnel 5 is two meters away from the bridge pile foundation 3 .

[0030] Furthermore, in the embodiment, it can also be considered that in the step S2, the initial support of the guide tunnel 5 adopts grid support, and a grid node plate of the large arch portion 10 is reserved on the grid.

[0031] Furthermore, it can also be considered in the embodiment that in the step S4, the initial support of the main body adopts a large arch initial support grid, the foot of the grid is connected to the embedded steel bars on the crown beam 2, and the upper part of the grid is connected to the grid node plate reserved in the guide tunnel 5.

[0032] The primary support grid of the large arch in the middle section of the large arch portion 10 is connected to the reserved node plate outside the guide tunnel grid.

[0033] Furthermore, in the embodiment, it can also be considered that when the large arch portion 10 is excavated, the excavation step distance is equal to the spacing of the initial support grids of the large arch.

[0034] Furthermore, in the embodiment, it can also be considered that in the step S3, the water-stop curtain is an ultra-high pressure jet mixing pile 13 .

[0035] Furthermore, it can also be considered in the embodiment that in the step S4, the main body advance support adopts the large pipe rack and deep hole grouting support of the large arch part 10.

[0036] The large arch 10 needs to be constructed with a large pipe shed and grouting pre-reinforcement is required to protect the existing bridge 4. The advantage of the large arch large pipe shed as the main advance support is that it can be built quickly and provides temporary support and protection functions.

[0037] Large pipe sheds are usually used as the main advance support system in underground projects. They have a stable structure and are used to protect the safety of underground construction areas.

[0038] The span of the large arch 10 is larger than that of an ordinary island station. In this embodiment, the span of the large arch 10 is 11.6 meters, and the internal space of the station 1 structure is large. When excavating the large arch 10, the excavation is carried out according to the sequential step method. Figure 2 The a and b sequential step methods shown (the standard section adopts the full section method) excavate a earthwork 8 and b earthwork 9.

[0039] Furthermore, it can also be considered in the embodiment that in the step S5, the secondary lining structure 22 is constructed from the middle position of the two transverse passages backward in the direction of the transverse passages, and the guide tunnel 5 support is dismantled in sections along the longitudinal direction of the station 1.

[0040] The secondary lining structure 22 is constructed from the middle position of the two transverse passages backwards towards the transverse passages. The initial support of the guide tunnel should be removed in sections along the longitudinal direction of the station 1. The initial support length of the guide tunnel removed at one time should not exceed 6m.

[0041] When pouring the secondary lining structure 22, pay attention to reserving the steel bar connectors of the side wall 21; Furthermore, in the embodiment, it can also be considered that in the step S6, the side wall 21 and the middle plate 11 are cast at one time, and steel bars of the rail top air duct 20 are reserved on the middle plate 11.

[0042] The side wall 21 and the middle plate 11 need to be cast at one time. The concrete support is constructed after the side wall 21 reaches the designed strength. The middle plate 11 should reserve steel bars for the rail top air duct 20, and waterproof plates and steel bar connectors should be reserved under the side walls.

[0043] Furthermore, in the embodiment, it can be considered that in the step S8, a communication passage 19 connecting the concourse layer 17 and the platform layer 15 is set between the separate concourse and the platform, and the communication passage 19 is constructed by the CRD method, which is the cross-wall method.

[0044] The length of the communication channel 19 is generally 10m. The communication channel 19 is set according to the function of the building. Generally, there are three entrances and exits 18 in the public area. One entrance and exit 18 is set at the platform level 15 and the station hall level 17, and one entrance is set in the central paid area of ​​the public area.

[0045] The distance between adjacent communication channels 19 is about 50~70m. The equipment area is set up according to equipment requirements. The distance between communication channels 19 on the platform level 15 is generally 50~70m, and the distance between adjacent communication channels 19 on the concourse level 17 is about 20~30m.

[0046] The connecting channel 19 improves the transfer efficiency and the efficiency of traffic connection between the ground and underground spaces on both sides of the road.

[0047] The above embodiments describe the present invention in detail, but the contents are only preferred embodiments of the present invention and cannot be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. A method for constructing a subway separated island type underground excavation station, characterized in that: The following steps are involved: Step S1: excavating a vertical shaft and a construction transverse passage connecting the pilot tunnel; Avoid the existing bridge pile foundation (3), excavate the vertical shaft and provide support, and excavate the construction cross passage on both sides of the bridge pile foundation (3); Step S2: constructing a pilot tunnel (5) and providing support; Constructing an advance support structure for the arch of the pilot tunnel (5), and reinforcing the stratum by grouting, excavating the earthwork inside the pilot tunnel (5) by using a step method, and providing support; Step S3: construct bored cast-in-place piles, water-stop curtains, and cap beams (2) on the piles; Constructing bored cast-in-place piles and water-stop curtains in the pilot tunnel (5), chiseling away the pile heads and constructing cap beams (2) on the piles; Step S4: performing main body advance support and main body initial support, and excavating earthwork of the large arch part (10); Constructing a large pipe shed for the large arch (10), grouting to pre-reinforce the stratum of the large arch (10), excavating the earth of the large arch (10), constructing the main body initial support, and strengthening monitoring and measurement; Step S5: casting the secondary lining structure (22) of the large arch portion (10); After the space below the large arch (10) is connected, the secondary lining structure (22) is constructed, the support of the pilot hole (5) is removed, the waterproof board of the large arch (10) is laid, and the secondary lining structure (22) of the large arch (10) is poured, and monitoring and measurement are strengthened during the construction process; Step S6: pouring the side wall (21) and the middle plate (11); Continue to dig downwards, apply sprayed concrete and waterproofing boards between the retaining pile foundations (6), use the soil at the bottom of the pit to set up formwork supports, and cast the side walls (21) and the middle plate (11); Step S7: constructing the structural base plate (12) and the side walls (21); After excavating to the bottom of the pit, quickly construct the bottom cushion of the structure, lay the waterproof layer, and construct the bottom plate (12) and side wall (21); Step S8: constructing a communication channel (19); A communication passage (19) connecting the two separate station halls and platforms is excavated between the bridge pile foundations (3) and a lining structure is constructed; Step S9: constructing the platform plate (16) and the rail top air duct (20); The platform plate (16), supporting wall and track top air duct (20) are constructed to complete the main construction.

2. The method for constructing a subway separated island type underground excavation station according to claim 1, characterized in that: In the step S1, the transverse passage is constructed by opening a horse head door in the vertical shaft, and the guide tunnel (5) is constructed by opening a horse head door in the transverse passage.

3. The method for constructing a subway separated island type underground excavation station according to claim 1, characterized in that: In the step S2, the initial support of the guide tunnel (5) adopts grid support, and a grid node plate of the large arch portion (10) is reserved on the grid.

4. The method for constructing a subway separated island type underground excavation station according to claim 3, characterized in that: In step S4, the main body initial support adopts a large arch initial support grid, the foot of the grid is connected to the embedded steel bars on the crown beam (2), and the upper part of the grid is connected to the grid node plate reserved in the guide tunnel (5).

5. The method for constructing a subway separated island type underground excavation station according to claim 4, characterized in that: When the large arch portion (10) is excavated, the excavation step distance is equal to the spacing of the initial support grids of the large arch.

6. The method for constructing a subway separated island type underground excavation station according to claim 1, characterized in that: In step S3, the water-stop curtain is an ultra-high pressure jet mixing pile (13).

7. The method for constructing a subway separated island type underground excavation station according to claim 1, characterized in that: In step S4, the main body advance support adopts a large pipe shed and deep hole grouting support of the large arch part (10).

8. The method for constructing a subway separated island type underground excavation station according to claim 1, characterized in that: In step S5, the secondary lining structure (22) is constructed from the middle position of the two transverse passages backward in the direction of the transverse passages, and the guide tunnel (5) support is removed in sections along the longitudinal direction of the station (1).

9. The method for constructing a subway separated island type underground excavation station according to claim 1, characterized in that: In the step S6, the side wall (21) and the middle plate (11) are cast at one time, and steel bars for the rail top air duct (20) are reserved on the middle plate (11).

10. The method for constructing a subway separated island type underground excavation station according to claim 1, characterized in that: In the step S8, a communication passage (19) connecting the station hall layer (17) and the platform layer (15) is set between the separated station hall and the platform, and the communication passage (19) is constructed by the CRD method.

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