A construction method and structure of a stacked tunnel communication channel

Abstract

The present invention provides a construction method and structure of a communication channel of a stacked tunnel, which is characterized by: first setting up an open-cut shaft structure, and combining the internal structure arrangement of the shaft, forming a reinforced concrete structure closed space around the intended crossing range of the up and down shield tunnels; backfilling water and sand in the shaft and outside the reinforced concrete structure closed space, and before and after the shield tunnel is excavated to the shaft, the down and up shield tunnels are successively excavated through the backfill body of the shaft; after the up tunnel passes through the shaft, the backfill water and sand in the shaft are pumped out, and a transverse channel is secretly excavated in the backfill body of the shaft, and finally the remaining auxiliary structures are completed in the shaft. The present invention is suitable for tunnels between up and down sections with large elevation differences, and the shield tunnel is secretly received and started by backfilling in the shaft, and a communication channel is secretly excavated in the backfill body, which shortens the construction period, reduces the project investment, and reduces the construction risk.

Description

Technical Field

[0001] The invention relates to the field of subway engineering, and in particular to a construction method and structure of a stacked-line tunnel communication channel. Background Art

[0002] A connecting passage is a passage or doorway connecting two upstream and downstream tunnels on the same line. It is used for passengers to safely evacuate from the accident tunnel to the non-accident tunnel when the train is suspended due to a fire or other disaster or accident in the section.

[0003] According to the "Metro Design Code" (GB50157-2013), two single-track section tunnels should have a connecting channel, and the distance between two adjacent connecting channels should not be greater than 600m; when conditions permit, the section drainage pump station should be built together with the section connecting channel or the intermediate ventilation shaft.

[0004] With the rapid development of urban subway construction, there are more and more underground hub stations and lines of rail transit. Newly built lines are increasingly restricted by the surrounding environment, and more and more up and down tunnels with overlapping lines or large elevation differences are appearing.

[0005] like Figure 2a to 2c As shown, a transverse passage is set between the uplink and downlink overlapping tunnels. Usually, an open-cut shaft structure is set up first. When the shield tunnel is excavated to the shaft, the downlink shield tunnel reaches the shaft first and then starts from the shaft. The process of the uplink tunnel entering the shaft is similar. After the uplink and downlink tunnels pass through the shaft, the connecting passage and other ancillary structures are completed in the shaft.

[0006] Before the up and down shield tunnels reach and start the vertical shaft, the strata around the shield need to be reinforced (the longitudinal length is generally 9m) to ensure the stability of the external soil and no groundwater leakage during the opening of the shield portal (a circle with a diameter of 6700mm).

[0007] When the upper tunnel passes through the vertical shaft, the shield machine has a large body weight (generally 150-250t), and temporary supports need to be erected on the running board structure at the bottom of the tunnel to ensure the safety of the running board structure. After the shield machine passes through the vertical shaft, the temporary supports are removed.

[0008] After the up and down tunnels of the shield machine pass through the vertical shaft, an external tunnel door is set at the connection between the shield tunnel and the vertical shaft structure to ensure that water and soil outside the shield tunnel do not enter the vertical shaft.

[0009] When this method is used for construction, a single tunnel reaches the shaft, undergoes mechanical maintenance, and starts in sequence, with a construction period of 3 months and high construction risks. Summary of the invention

[0010] In view of the above problems, the present invention provides a construction method and structure of a connecting channel in a stacked tunnel, which is suitable for use between up and down tunnels with a large height difference. The method realizes the hidden reception and hidden starting of the shield tunnel by backfilling in the vertical shaft, and the connecting channel is secretly excavated in the backfill body, thereby shortening the construction period, reducing project investment, and lowering construction risks.

[0011] The first object of the present invention is to provide a method for constructing a connecting channel of a stacked tunnel, comprising the following steps:

[0012] The first step is to excavate the open-cut shaft structure and cast each support in batches. When constructing the support, it is necessary to simultaneously construct the up and down tunnel portal ring beams and cast the structural bottom plate to complete the main load-bearing structure inside the open-cut shaft. Cast the driving plate structure, floor structure, and side wall structure from bottom to top;

[0013] Combined with the internal structure layout of the shaft, a reinforced concrete structure enclosed space is formed around the planned crossing range of the up and down shield tunnels, the support and enclosure structures within the tunnel opening range are dismantled layer by layer, and plastic concrete is backfilled in time to complete the shaft structure;

[0014] The second step is to backfill water and sand inside the shaft and outside the plastic concrete after the backfill plastic concrete reaches the designed strength;

[0015] First, the downgoing shield tunnel is pushed directly through the shaft, and then the upgoing shield tunnel is pushed directly through the shaft;

[0016] After the up and down shield tunnels pass through the shaft, secondary grouting is carried out in time to ensure that the gaps between the shield segments and the backfill are densely filled;

[0017] The third step is to drain the backfill water and sand, dig a horizontal passage in the plastic concrete, cast the supporting structure in time after the digging is completed, and finally complete the internal evacuation stairs. The digging horizontal passage and the evacuation stairs form a connecting channel between the upward and downward tunnels.

[0018] Furthermore, the transverse channel adopts a rectangular frame structure.

[0019] The second object of the present invention is to provide a construction structure for a stacked tunnel communication channel, including an open-cut vertical shaft and an up-and-down tunnel portal ring beam, characterized in that a reinforced concrete structure is arranged in the vertical shaft within the range where the shield tunnel is to pass, and water and sand are backfilled in the vertical shaft and outside the reinforced concrete structure.

[0020] The beneficial effects of the present invention are:

[0021] 1. The present invention is suitable for solving the problem of building communication channels between up and down tunnels with large height differences when the ground site is small, the construction safety requirements are high, and the investment costs are strict. It can also be used for the construction of communication channels with high risks for receiving and starting construction of parallel shield tunnels.

[0022] 2. The present invention adopts backfill plastic concrete in the vertical shaft to realize the hidden reception and hidden starting of the shield tunnel, and then constructs the horizontal passage inside the backfill body. Compared with the traditional construction technology, it greatly reduces the construction risk, shortens the construction period by 2 months, and reduces the project investment by 6 million yuan.

[0023] 3. There is a shield tunnel of a certain length between the cross section of the underground excavated cross channel and the surrounding soil. Through the synchronous grouting and secondary grouting of the shield tunnel, a water-blocking channel is formed. When the underground excavated cross channel is constructed in the backfill body, the risk of underground excavation of the cross channel is greatly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the plan structure of the stacked tunnel and vertical shaft.

[0025] Figure 2a This is a schematic diagram of the construction process of the existing overlapping tunnel connecting channel.

[0026] Figure 2b This is a schematic diagram of the second construction process of the existing overlapping tunnel connecting channel.

[0027] Figure 2c This is a schematic diagram of the third construction process of the existing overlapping tunnel connecting channel.

[0028] Figure 3a It is a schematic diagram of the construction process of the stacked tunnel communication channel of the present invention.

[0029] Figure 3b It is a schematic diagram of the second construction process of the stacked tunnel communication channel of the present invention.

[0030] Figure 3c It is a schematic diagram of the third construction process of the stacked tunnel communication channel of the present invention.

[0031] In the figure: 0-vertical shaft, 1-enclosing structure, 2-side wall structure, 3-driving plate structure, 4-floor structure, 5-structural bottom plate, 6-portal ring beam, 7-shield tunnel, 8-evacuation stairs, 9-steel frame support, 10-plastic concrete, 11-cross passage, 12-pump room, 13-water and sand, 14-support structure. DETAILED DESCRIPTION

[0032] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0033] like Figure 3a to 3c As shown, a construction method for a stacked tunnel communication channel includes the following steps:

[0034] The first step is to excavate the open-cut shaft structure 0, cast each support in batches, and simultaneously construct the up and down tunnel portal ring beams 6 and cast the structural bottom plate 5 when constructing the support, so as to complete the main load-bearing structure inside the open-cut shaft. Cast the driving plate structure 3, floor structure 4, and side wall structure 2 from bottom to top; combined with the internal structure layout of the shaft, form a reinforced concrete structure enclosed space around the planned crossing range of the up and down shield tunnels, dismantle the support and enclosure structures within the tunnel opening range in layers, and backfill the plastic concrete 10 in time to complete the shaft structure.

[0035] The second step is to backfill water and sand 13 inside the shaft and outside the plastic concrete 10 after the backfill plastic concrete 10 reaches the design strength; first push the down shield tunnel 7 directly through the shaft, and then push the up shield tunnel 7 directly through the shaft; after the up and down shield tunnels 7 pass through the shaft, carry out secondary grouting in time to ensure that the gaps between the shield segments and the backfill body are backfilled densely.

[0036] The third step is to drain the backfill water and sand 13, dig a transverse passage 11 in the plastic concrete 10, cast the supporting structure 14 in time after the digging is completed, and finally complete the internal evacuation staircase 8. The digging transverse passage and the evacuation staircase 8 form a communication passage between the up and down tunnels.

[0037] Since the tunnel gate is broken down while plastic concrete is backfilled, the possibility of water and sand gushing during construction is small, and the construction safety is greater.

[0038] When the up tunnel passes through the shaft, the shield machine has a large body weight (generally 150-250t), and the safety of the running board structure at the bottom of the tunnel needs to be given special consideration. By backfilling water and sand in the shaft 13, the water and soil pressure around the shield machine is relatively balanced, and the safety of its running board structure is greatly enhanced. After the shield machine passes through the shaft, the backfill water and sand can be pumped out.

[0039] After the up and down tunnels of the shield machine pass through the vertical shaft, there is only a transverse passage 11 at the connection between the shield tunnel and the vertical shaft structure, and there is no need to set up an external tunnel door. Moreover, the transverse passage 11 is excavated in the plastic concrete 10. The plastic concrete has good strength and water-stopping properties, and the construction risk is low. Water and soil outside the shield tunnel are not easy to enter the vertical shaft.

[0040] In order to facilitate the construction of the underground excavation of the cross passage in the backfill body, the cross passage adopts a rectangular frame structure with a clearance of 1000×2100mm in the frame to facilitate the installation of fire doors and personnel evacuation.

[0041] If a drainage pump room is required, it is only necessary to drill a hole inside the shaft through the side wall of the shaft structure and the backfill body to reach the vicinity of the tunnel structure floor.

[0042] By adopting the construction method of the present invention, the construction process is simple. A single tunnel only needs to be directly excavated through the vertical shaft and the horizontal passage is secretly excavated. The construction period is 1 month, the project investment is small, and the construction risk is low.

[0043] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

Claims

1. A construction method for a stacked tunnel communication channel, characterized in that: The steps include: The first step is to excavate the open-cut shaft (0) structure, cast each support in stages, and simultaneously construct the up and down tunnel portal ring beams (6) and cast the structural bottom plate (5) to complete the main load-bearing structure inside the open-cut shaft; cast the driving plate structure (3), floor structure (4), and side wall structure (2) from bottom to top; In combination with the internal structural arrangement of the shaft, a reinforced concrete structure enclosed space is formed around the intended traversing range of the up and down shield tunnels (7), the supporting and surrounding structures within the opening range of the up and down shield tunnels (7) are dismantled in layers, and plastic concrete (10) is backfilled in time to complete the shaft structure; The second step is to backfill water and sand (13) inside the shaft and outside the plastic concrete (10) after the backfilled plastic concrete (10) reaches the designed strength; First, the downgoing shield tunnel is pushed directly through the shaft, and then the upgoing shield tunnel is pushed directly through the shaft; After the up and down shield tunnels (7) pass through the shaft, secondary grouting is promptly performed to ensure that the gaps between the shield segments and the backfill body are densely backfilled; The third step is to drain the backfilled water and sand (13), and then to dig a transverse passage (11) in the plastic concrete (10). After the digging is completed, the supporting structure (14) is cast in time, and finally the internal evacuation staircase (8) is completed. The digging transverse passage and the evacuation staircase (8) form a communication passage between the up and down shield tunnels (7); It is used to solve the problem of building a communication channel between up and down shield tunnels (7) with a large height difference, and is also used for the construction of a communication channel with high risks for receiving and starting construction of parallel shield tunnels.

2. A method for constructing a connecting channel of a stacked tunnel according to claim 1, characterized in that: The transverse channel (11) adopts a rectangular frame structure.

3. A construction structure using the construction method of a stacked tunnel communication channel as claimed in claim 1, comprising an open-cut shaft (0), an up-and-down tunnel portal ring beam (6), characterized in that: It also includes a reinforced concrete structure arranged in the vertical shaft within the range where the up-and-down shield tunnel (7) is to pass, and water and sand (13) backfilled in the vertical shaft and outside the reinforced concrete structure.

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