A construction method for a subway separated island-type underground excavation station

Abstract

The present invention discloses a method for constructing a subway separated island-type underground station, comprising the following steps: excavating a vertical shaft and a construction transverse passage connecting to a pilot tunnel; constructing and supporting the pilot tunnel; constructing a retaining structure, a water-stop curtain, and a cap beam on the piles; implementing advance support and initial support, excavating the large arch section; pouring the arch section secondary lining structure; pouring the side walls and center plate; constructing the structural floor and side walls; constructing a connecting passage; and constructing the platform slab and track-top air duct. This method has the advantages of a safe and reliable construction process, low economic cost, and minimal environmental impact. It also offers advantages such as good passenger usability, high underground space utilization, and convenient connection to surrounding transportation and urban space, and has broad prospects for promotion.

Description

Technical Field

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

[0002] To meet citizens' needs for convenient transportation, subway stations are often located in busy urban areas, often needing to be built beneath existing elevated roads. However, due to the limited width of existing roads, the main structure of the subway station must inevitably be located under existing bridges. Due to clearance restrictions under bridges, open-cut construction often requires the demolition of existing bridges. Excavating the entire station structure using the standard PBA method would also conflict with existing bridge piles. Therefore, it is crucial to find a construction method that fully utilizes the narrow space on both sides of the pile foundation under the road while protecting the bridge piles. Summary of the Invention

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

[0004] A method for constructing a subway separated island type underground excavation station comprises the following steps:

[0005] Step S1: excavating a vertical shaft and a construction cross passage connecting the pilot tunnel;

[0006] Avoid existing bridge pile foundations, excavate and support vertical shafts, and excavate and construct cross passages on both sides of the bridge pile foundations;

[0007] Step S2: constructing a pilot tunnel and providing support;

[0008] Construct the advanced support structure of the arch of pilot tunnel 5, reinforce the stratum with grouting, excavate the earthwork in the pilot tunnel using the step method, and provide support;

[0009] Step S3: construct bored cast-in-place piles, water-stop curtains, and crown beams on the piles;

[0010] 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;

[0011] Step S4: Perform main body advance support and main body initial support, and excavate the earthwork of the large arch;

[0012] Construct a large pipe shed for the large arch, pre-reinforce the ground at the large arch by grouting, excavate the earth at the large arch, implement initial support for the main structure, and strengthen monitoring and measurement;

[0013] Step S5: pouring the secondary lining structure of the large arch;

[0014] After the space under the arch is penetrated, the secondary lining structure is constructed, the pilot 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;

[0015] Step S6: pouring side walls and middle plates;

[0016] Continue excavating downwards, apply sprayed concrete and waterproof panels between the retaining piles, use the soil at the bottom of the pit to erect formwork supports, and cast the side walls and middle slabs;

[0017] Step S7: constructing the structural base plate and side walls;

[0018] 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;

[0019] Step S8: constructing a communication channel;

[0020] Excavate a connecting passage between the two separate station halls and platforms between the bridge pile foundations and construct the lining structure;

[0021] Step S9: constructing the platform plate and the rail top air duct;

[0022] The platform slab, supporting walls and track-top air ducts are constructed to complete the main construction.

[0023] Preferably, in step S1, the transverse passage is constructed by opening a horse head door in the vertical shaft, and the pilot tunnel is constructed by opening a horse head door in the transverse passage.

[0024] Preferably, in step S2, the initial support of the pilot tunnel adopts grid support, and a grid node plate of the large arch portion is reserved on the grid.

[0025] Further preferably, in step S4, the main body initial support adopts a large arch primary 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.

[0026] 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.

[0027] Preferably, in step S3, the water-stop curtain is an ultra-high pressure jet mixing pile.

[0028] Preferably, in step S4, the main body advance support adopts a large pipe shed and deep hole grouting support for the large arch part.

[0029] Preferably, in step S5, the secondary lining structure is constructed from the middle position of the two transverse passages backward in the direction of the transverse passages, and the guide tunnel support is dismantled in sections along the longitudinal direction of the station.

[0030] Preferably, in step S6, the side walls 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.

[0031] Preferably, in step S8, a communication channel connecting the station hall layer and the platform layer is set between the separated station hall and the platform, and the communication channel is constructed by the CRD method.

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

[0033] (1) By dividing the main body of the station into two and setting it up close to the existing road bridge piles, the utilization rate of underground space is fully improved, the impact on surrounding plots is reduced, and the overall development benefits of the node city are significant; the split station is constructed by adopting the dark excavation method, 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, small environmental impact and obvious social benefits.

[0034] (2) The platform level and the concourse level of the split station are quickly connected through a connecting passage that avoids the 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 for management, and it is convenient for passengers to turn back on the way. Passengers on 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.

[0035] (3) There are no columns in the middle of the left and right line separated stations. It is a single-span column-free large space structure, which provides a good visual effect for passengers. The arched space on the station hall 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.

[0036] (4) The structure and construction method described in the present invention have the advantages of safe and reliable construction technology, 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 promotion prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The technical solutions of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. However, it should be understood that these drawings are designed for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, unless otherwise specified, these drawings are intended only to conceptually illustrate the structures described herein and are not necessarily drawn to scale.

[0038] Figure 1 This is a schematic diagram of the station and bridge pile locations;

[0039] Figure 2It is the structure of part of the construction sequence Figure 1 ;

[0040] Figure 3 It is the structure of part of the construction sequence Figure 2 ;

[0041] Figure 4 It is the structure of part of the construction sequence Figure 3 ;

[0042] Figure 5 It is a cross-sectional view of the main body;

[0043] Figure 6 It is a plan view of the platform level;

[0044] Figure 7 This is a schematic diagram of the station hall level;

[0045] Figure 8 It is a flow chart of the construction method of the present invention.

[0046] In the picture:

[0047] 1-Station; 2-Crown beam; 3-Bridge pile foundation; 4-Bridge; 5-Pilot tunnel; 6-Retaining pile foundation; 7-Platform; 8- Earthwork a; 9-Earthwork b; 10-Large arch; 11-Middle plate; 12-Structural bottom plate; 13-Ultra-high pressure jet mixing piles; 14-Track surface; 15-Platform level; 16-Platform slab; 17-Concourse level; 18-Entrance and exit; 19-Connecting passage; 20-Track top air duct; 21-Side wall; 22-Secondary lining structure. DETAILED DESCRIPTION

[0048] First, it should be noted that the specific structure, features, and advantages of the present invention will be described in detail below by way of example. However, all descriptions are for illustrative purposes only and should not be understood as limiting the present invention in any way. In addition, any single technical feature described or implied in the embodiments mentioned herein, or any single technical feature shown or implied in the drawings, can still be combined or deleted in any way between these technical features (or their equivalents), thereby obtaining more other embodiments of the present invention that may not be directly mentioned herein. In addition, for the sake of simplifying the drawings, the same or similar technical features may be marked in only one place in the same drawing.

[0049] In the present invention, unless otherwise clearly stipulated and limited, the terms "install", "set", "connect", "fix", "screw" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; 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.

[0050] The following is combined with Figure 1 -Attached Figure 8 The present invention will be described in detail. Example 1

[0051] A method for constructing a subway separated island type underground excavation station comprises the following steps:

[0052] Step S1: excavating a vertical shaft and a construction cross passage connecting the pilot tunnel;

[0053] Avoid the existing bridge pile foundation 3, excavate the vertical shaft and support it, and excavate the construction cross passage on both sides of the bridge pile foundation 3;

[0054] Step S2: constructing a pilot tunnel 5 and providing support;

[0055] Construct the advanced support structure of the arch of pilot tunnel 5, reinforce the stratum with grouting, excavate the earthwork inside pilot tunnel 5 using the step method, and provide support;

[0056] Step S3: construct bored cast-in-place piles, water-stop curtains, and crown beams 2 on the piles;

[0057] 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;

[0058] Step S4: Perform main body advance support and main body initial support, and excavate the earthwork of the large arch;

[0059] Construct a large pipe shed for the large arch, pre-reinforce the ground at the large arch by grouting, excavate the earth at the large arch, implement initial support for the main structure, and strengthen monitoring and measurement;

[0060] Step S5: Casting the secondary lining structure 22 of the large arch portion 10;

[0061] 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. During the construction process, monitoring and measurement are strengthened;

[0062] Step S6: pouring the side walls 21 and the middle plate 11;

[0063] Continue excavating downwards, construct six retaining pile foundations with sprayed concrete and waterproof panels, use the soil at the bottom of the pit to erect formwork, and cast the side walls 21 and the middle plate 11;

[0064] Step S7: constructing the structural base plate 12 and the side walls 21;

[0065] After excavating to the bottom of the pit, quickly construct the bottom cushion of the structure, lay the waterproof layer, and construct the structural bottom plate 12 and side walls 21;

[0066] Step S8: constructing the communication channel 19;

[0067] A connecting passage 19 connecting the two separate station halls and platforms is excavated between the bridge pile foundations 3 and a lining structure is constructed;

[0068] Step S9: constructing the platform plate 16 and the rail top air duct 20;

[0069] The platform slab 16, supporting wall and track top air duct 20 are constructed to complete the main construction.

[0070] Working principle:

[0071] The present invention is based on the traditional underground 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 set close to the bridge pile foundation 3, and connects them through a communication channel 19 to form a whole.

[0072] The construction steps are as follows: construct vertical shafts, horizontal passages and guide tunnels 5; construct initial support for the large arch 10; cast the secondary lining structure 22 of the large arch 10; cast the side walls 21 and the middle plate 11; cast the side walls 21, construct the structural bottom plate 12 and the side walls 21; construct connecting passages; construct the platform plate 16, support walls and track top air duct 20 to complete the main construction.

[0073] Compared with the traditional open-cut method, this method can excavate the station 1 under the low-headroom bridge and on both sides of the bridge pile foundation 3, which is generally difficult to excavate;

[0074] Compared with traditional underground excavation island stations, this construction method can be used to construct column-free separated island stations with larger single arch spans.

[0075] Compared with the side-type station, this construction method cleverly connects the separate 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.

[0076] Furthermore, in the embodiment, it can also be considered 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.

[0077] In this embodiment, the bridge pile foundation 3 does not need to be removed when the vertical shaft is excavated, and the pilot tunnel 5 is arranged close to the existing bridge pile foundation 3, and the pilot tunnel 5 is two meters away from the bridge pile foundation 3.

[0078] Furthermore, in the embodiment, it can also be considered that in the step S2, the initial support of the pilot tunnel 5 adopts grid support, and a grid node plate of the large arch portion 10 is reserved on the grid.

[0079] Furthermore, in the embodiment, it can also be considered that in 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.

[0080] 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 on the outer side of the pilot tunnel grid.

[0081] 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 large arch primary support grids.

[0082] 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.

[0083] Furthermore, in the embodiment, it can also be considered that in the step S4, the main body advance support adopts the large pipe roof and deep hole grouting support of the large arch part 10.

[0084] The large arch portion 10 needs to be constructed with a large pipe shed and grouting pre-reinforced to protect the existing bridge 4. The advantage of the large pipe shed for the large arch portion as the main advance support is that it can be built quickly and provides temporary support and protection functions.

[0085] Large pipe roofs are usually used as the main advance support system in underground projects. Their structure is stable and is used to protect the safety of underground construction areas.

[0086] 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 is large. When excavating the large arch 10, the excavation is carried out in a sequential step method. Figure 2 The a and b sequential step methods shown (the standard section uses the full section method) are used to excavate a soil 8 and b soil 9.

[0087] Furthermore, in the embodiment, it can also be considered 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.

[0088] The secondary lining structure 22 is constructed from the middle position between the two transverse passages backward toward the transverse passage. The initial support of the pilot tunnel should be removed in sections along the longitudinal direction of station 1. The length of the initial support of the pilot tunnel removed at one time shall not exceed 6m.

[0089] When pouring the secondary lining structure 22, be sure to reserve the steel bar connectors for the side wall 21;

[0090] 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 for the rail top air duct 20 are reserved on the middle plate 11.

[0091] The side walls 21 and the middle plate 11 need to be cast at one time. The concrete support is constructed after the side walls 21 reach the designed strength. The middle plate 11 should reserve steel bars for the rail top air duct 20, and waterproof boards and steel bar connectors should be reserved under the side walls.

[0092] Furthermore, in the embodiment, it is also conceivable that in step S8, a connecting passage 19 is provided between the separate concourse and platform to connect the concourse level 17 and the platform level 15, and the connecting passage 19 is constructed by the CRD method, which is the cross-wall method.

[0093] The length of the communication channel 19 is generally 10m. The communication channel 19 is set according to the function of the building. There are generally three communication channels in the public area. There is one entrance and exit 18 each on the platform level 15 and the station hall level 17, and one paid area in the center of the public area.

[0094] The distance between adjacent connecting channels 19 is about 50~70m. The equipment area is set up according to equipment requirements. The distance between connecting channels 19 on the platform level 15 is generally 50~70m, and the distance between adjacent connecting channels 19 on the concourse level 17 is about 20~30m.

[0095] Connecting channel 19 improves transfer efficiency and the efficiency of traffic connection between the ground and underground spaces on both sides of the road.

[0096] The above embodiments describe the present invention in detail, but the contents described are only preferred embodiments of the present invention and should not 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 patent coverage 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 cross passage connecting the pilot tunnel; Avoid the existing bridge pile foundation (3), excavate the vertical shaft and support it, 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 the arch advance support structure of the pilot tunnel (5), and reinforcing the stratum by grouting, excavating the soil inside the pilot tunnel (5) by using the step method, and providing support; Step S3: construct bored cast-in-place piles, water-stop curtains, and crown 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: Perform main body advance support and main body initial support, and excavate the earthwork of the large arch part (10); Construct a large pipe shed for the large arch (10), pre-reinforce the ground of the large arch (10) by grouting, excavate the earthwork of the large arch (10), construct the main body initial support, 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 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 walls (21) and the middle plate (11); Continue to excavate 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 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 structural bottom plate (12) and side walls (21); Step S8: constructing a communication channel (19); A connecting passage (19) is excavated between the bridge pile foundations (3) to connect the two separate station halls and platforms 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 pilot 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 pilot 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 hole (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 primary 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-mixed 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 dismantled 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 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) is provided between the separated station hall and the platform, connecting the station hall layer (17) and the platform layer (15), and the communication passage (19) is constructed by the CRD method.

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