Mining method horseshoe-shaped tunnel supporting structure

Abstract

The utility model provides a mining method horseshoe-shaped tunnel supporting structure, and belongs to the technical field of underground engineering tunnel building structures. The structure comprises a tunnel primary supporting structure and a secondary lining structure arranged in the tunnel primary supporting structure, a supporting beam is arranged on the lower portion, located on one side of a soft layer, of the tunnel primary supporting structure, a pile foundation is arranged below the supporting beam, the upper end of the pile foundation is fixedly connected with the supporting beam, and a rigid pull anchor is anchored in a stable rock-soil body located on the lower portion of the other side of the tunnel primary supporting structure. And one end of the rigid pull anchor is fixedly connected with the joist. The method can be suitable for special unfavorable geological sections such as tunnel crossing fault tectonic zones and irregular karst development, and the problem of uneven structure settlement caused by uneven distribution of soft layers at the tunnel bottom can be solved.

Description

Technical Field

[0001] The utility model belongs to the technical field of underground engineering tunnel building structures and relates to a horseshoe-shaped tunnel supporting structure using a mining method. Background Art

[0002] The tunnel mainly passes through rock strata, and the tunnel bottom is on a stable foundation. However, due to the line direction, surrounding environment and geological conditions, the base of some sections in the tunnel is located in soft strata, and the bearing capacity of the tunnel base is low. In order to avoid water leakage, secondary lining cracking, uneven structural settlement and other diseases in the later stage of the tunnel, the weak layer at the tunnel bottom needs to be reinforced.

[0003] The weak layer at the bottom of the tunnel is usually a soft soil layer, a fault fracture zone, and a karst dissolution zone. According to the characteristics and thickness of different weak layers, tunnel bottom reinforcement measures such as concrete replacement, jet grouting piles, CFG piles, steel pipe grouting, and pile foundation beams are generally adopted. Considering the controllable risks and technical and economic rationality, concrete replacement is suitable for areas with shallow weak layers, and the composite foundation reinforcement of jet grouting piles, CFG piles, and steel pipe grouting is suitable for areas with deep weak layers and lax settlement control. The rigid foundation reinforcement of pile foundation beams is suitable for areas with deep weak layers and strict settlement control, such as railways with ballastless tracks, subway tunnels, and high-grade municipal and highway tunnels.

[0004] The mining tunnel generally adopts a horseshoe-shaped lining structure, which has a relatively uniform overall force and a large space utilization rate. When setting the pile foundation beam, a rectangular beam structure is generally used to replace the arc structure of the secondary lining arch wall. It is evenly arranged at the bottom of the tunnel. Reinforced concrete piles are generally symmetrically arranged under the beam, and the bottom of the pile is embedded in the stable rock and soil to ensure the overall stability of the tunnel structure. However, when the tunnel passes through special unfavorable geological sections with uneven distribution of weak layers at the bottom of the tunnel, such as fault tectonic zones and irregular karst development, it is easy to induce uneven settlement and deformation of the structure, and a conventional rectangular beam structure cannot be set. Therefore, in actual engineering, a pile foundation beam structure suitable for the secondary lining structure of the horseshoe tunnel is urgently needed to solve the problem of uneven settlement and deformation of the structure caused by the tunnel passing through special unfavorable geological sections with uneven distribution of weak layers at the bottom of the tunnel, such as fault tectonic zones and irregular karst development. Utility Model Content

[0005] The utility model aims to solve the above problems in the prior art and proposes a mine-method horseshoe-shaped tunnel support structure suitable for special areas such as irregular soft layers at the bottom of the tunnel.

[0006] The purpose of the utility model can be achieved through the following technical solutions:

[0007] A horseshoe-shaped tunnel support structure using the mining method comprises a tunnel primary support structure and a secondary lining structure arranged in the tunnel primary support structure, wherein a support beam is arranged at the lower part of the tunnel primary support structure on one side of a weak layer, a pile foundation is arranged below the support beam, the upper end of the pile foundation is fixedly connected to the support beam, a rigid anchor is anchored in the stable rock and soil body at the lower part of the other side of the tunnel primary support structure, and one end of the rigid anchor is fixedly connected to the support beam.

[0008] The primary support structure of the tunnel is horseshoe-shaped and consists of primary sprayed concrete, steel mesh, etc. The secondary lining structure is a reinforced concrete structure, which is horseshoe-shaped and cast on site. The cross-sectional width and height of the support beam are determined according to the actual development of the soft layer at the bottom of the tunnel. It can be applied to tunnels passing through fault tectonic zones, irregular karst development and other special unfavorable geological sections, and can solve the problem of uneven structural settlement caused by uneven distribution of the soft layer at the bottom of the tunnel.

[0009] In the above-mentioned horseshoe-shaped tunnel support structure of the mining method, the tunnel primary support structure includes an arch wall primary support structure and a tunnel bottom primary support structure, and the joist is fixed directly below the tunnel bottom primary support structure. After tunnel excavation, the arch wall primary support structure is constructed in time, and then the joist foundation pit is excavated downward at the reserved position of the tunnel bottom primary support structure, and the foundation pit primary support structure is constructed on both sides of the joist foundation pit. The joist can be conveniently constructed under the premise of ensuring safety.

[0010] In the above-mentioned horseshoe-shaped tunnel support structure of the mining method, a longitudinal hidden beam is provided in the support beam, the upper end of the pile foundation is fixedly connected to the longitudinal hidden beam, and the lower end of the pile foundation is embedded in the stable rock and soil. The longitudinal hidden beam connects a plurality of pile foundations distributed along the longitudinal direction of the tunnel together, which can improve the force bearing performance of the support beam.

[0011] In the above-mentioned horseshoe-shaped tunnel supporting structure of the mining method, primary support structures of the foundation pit are provided on both sides of the supporting beam.

[0012] In the above-mentioned horseshoe-shaped tunnel support structure of the mining method, the joist adopts a reinforced concrete structure, and vertical main reinforcement of the joist is arranged in the joist. The upper end of the vertical main reinforcement of the joist passes through the primary support structure of the tunnel bottom and then extends into the secondary lining structure.

[0013] When casting the joist, extend the upper end of the vertical main reinforcement of the joist to the casting area of ​​the secondary lining structure, and then cast the upper end of the vertical main reinforcement of the joist in the secondary lining structure.

[0014] In the above-mentioned horseshoe-shaped tunnel supporting structure of the mining method, one end of the rigid anchor is fixedly connected to the vertical main reinforcement of the supporting beam.

[0015] Rigid anchors can be made of large-diameter anchor rods or small tubes. The rigid anchors can be used to connect the support beams and stable rock and soil together. The three are combined to form an anchoring whole, which improves the overall stability. At the same time, the support beams and pile foundations on the other side can be saved. Under the premise of ensuring the safety of the project, it can effectively save construction time and reduce project investment.

[0016] In the above-mentioned horseshoe-shaped tunnel support structure of the mining method, the pile foundation adopts a reinforced concrete structure, and vertical main reinforcement of the pile body is arranged in the pile foundation, and the upper end of the vertical main reinforcement of the pile body extends into the longitudinal hidden beam.

[0017] When pouring the pile foundation, the vertical main reinforcement of the pile body is extended into the longitudinal hidden beam area. When constructing the longitudinal hidden beam, the upper end of the vertical main reinforcement of the pile body is poured into the longitudinal hidden beam.

[0018] The primary support structure and secondary lining structure of the tunnel bottom are constructed after the casting of the joist is completed. The joist is cast after the construction of the rigid anchor is completed. The rigid anchor is constructed after the casting of the pile foundation is completed. The pile foundation is constructed after the joist pit is expanded and the primary support structure of the pit on both sides is constructed. The joist pit is excavated after the primary support structure of the arch wall is completed. The primary support structure of the arch wall is constructed in time after the tunnel is excavated.

[0019] Compared with the prior art, the utility model has the following advantages: the structure can be applied to tunnels passing through fault structural zones, irregularly developed karst and other special unfavorable geological sections, and can solve the problem of uneven structural settlement caused by uneven distribution of weak layers at the bottom of the tunnel; the support beam and stable rock and soil are connected together by rigid anchors, and the three are combined to form an anchoring whole, which improves the overall stability, and at the same time can save the support beam and pile foundation on the other side, which can effectively save construction time and reduce project investment while ensuring the safety of the project. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a cross-sectional view of the horseshoe-shaped tunnel support structure of the mining method.

[0021] Figure 2 It is a plan view of the support beam in the first embodiment.

[0022] Figure 3 It is a plan view of the support beam in the second embodiment.

[0023] Figure 4 It is a cross-sectional view of the connection between the joist and the secondary lining structure.

[0024] Figure 5 It is a cross-sectional view of the connection between the pile foundation and the longitudinal hidden beam.

[0025] In the figure, 1. primary support structure of arch wall; 2. primary support structure of tunnel bottom; 3. secondary lining structure; 4. joist; 41. vertical main reinforcement of joist; 5. pile foundation; 51. vertical main reinforcement of pile body; 6. rigid anchor; 7. longitudinal hidden beam; 8. primary support structure of foundation pit. DETAILED DESCRIPTION

[0026] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0027] Embodiment 1

[0028] like Figure 1 The horseshoe-shaped tunnel support structure of the mining method shown in the figure includes a tunnel primary support structure and a secondary lining structure 3 arranged in the tunnel primary support structure. A joist 4 is arranged at the lower part of the tunnel primary support structure on the side of the weak layer. The joist 4 extends longitudinally along the tunnel. A pile foundation 5 with the lower end embedded in the stable rock and soil is arranged below the joist 4. A longitudinal hidden beam 7 is arranged in the joist 4. The longitudinal hidden beam 7 adopts a rectangular cross-section. The upper end of the pile foundation 5 is connected to the longitudinal hidden beam 7. A rigid anchor 6 is anchored in the stable rock and soil at the lower part of the other side of the tunnel primary support structure. One end of the rigid anchor 6 is fixedly connected to the joist 4. The rigid anchor can adopt a large-diameter anchor rod or a small guide tube. In this embodiment, as shown in FIG. Figure 2 As shown, the pile foundation 5 is a square pile.

[0029] like Figure 1 As shown, the tunnel primary support structure includes an arch wall primary support structure 1 and a tunnel bottom primary support structure 2, and the support beam 4 is fixed directly below the tunnel bottom primary support structure 2, which facilitates the construction of the support beam 4 below and effectively ensures the safety during the construction process.

[0030] This structure can be applied to tunnels passing through fault tectonic zones, irregular karst development and other special unfavorable geological sections, and can solve the problem of uneven structural settlement caused by uneven distribution of weak layers at the bottom of the tunnel. The primary support structure of the tunnel is horseshoe-shaped and consists of initial sprayed concrete, steel mesh, etc. The secondary lining structure 3 adopts a reinforced concrete structure, which is horseshoe-shaped and cast on site. The support beam 4 is supported by the pile foundation 5 and the rigid anchor 6, and the support beam 4 supports the primary support structure of the tunnel. The cross-sectional width and height of the support beam 4 are determined according to the actual development of the weak layer at the bottom of the tunnel.

[0031] like Figure 4 As shown, the joist 4 is of reinforced concrete structure, and a joist vertical main reinforcement 41 is arranged inside the joist 4. The upper end of the joist vertical main reinforcement 41 passes through the tunnel bottom primary support structure 2 and then extends into the secondary lining structure 3. One end of the rigid anchor 6 is fixedly connected to the joist vertical main reinforcement 41.

[0032] like Figure 5 As shown, the pile foundation 5 adopts a reinforced concrete structure, and a pile body vertical main reinforcement 51 is arranged in the pile foundation 5, and the upper end of the pile body vertical main reinforcement 51 extends into the longitudinal hidden beam 7.

[0033] The construction method of the horseshoe-shaped tunnel support structure of the mining method comprises the following steps:

[0034] S1. After tunnel excavation, the primary support structure of the arch wall should be constructed in time 1;

[0035] S2, excavate the foundation pit of the joist 4 downwards at the reserved place of the primary support structure 2 at the bottom of the tunnel to the bottom elevation of the foundation pit of the joist 4, and construct the foundation pit primary support structure 8 on both sides of the foundation pit of the joist 4;

[0036] S3, construct the pile foundation 5 at the bottom of the foundation pit of the joist 4, the bottom of the pile foundation 5 needs to be embedded in the stable rock and soil below, the upper end of the vertical main reinforcement 51 of the pile body is extended to the casting area of ​​the longitudinal hidden beam 7, the upper end of the vertical main reinforcement 51 of the pile body is cast in the longitudinal hidden beam 7, and then the longitudinal hidden beam 7 is constructed;

[0037] S4, construct a rigid anchor 6 on the other side of the foundation pit of the joist 4, fix one end of the rigid anchor 6 to the vertical main reinforcement 41 of the joist 4, and drive the other end of the rigid anchor 6 into the stable rock and soil;

[0038] S5, extending the upper end of the vertical main reinforcement 41 of the joist to the casting area of ​​the secondary lining structure 3, casting the joist 4, and casting one end of the rigid anchor 6 in the joist 4;

[0039] S6, pouring the primary support structure 2 at the bottom of the tunnel;

[0040] S7, pouring the secondary lining structure 3, and pouring the upper end of the vertical main reinforcement 41 of the joist into the secondary lining structure 3.

[0041] Embodiment 2

[0042] The structural principle of this embodiment is basically the same as that of the first embodiment, except that Figure 3 As shown, the pile foundation 5 is a round pile.

[0043] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A horseshoe-shaped tunnel support structure of mining method, characterized in that: It includes a tunnel primary support structure and a secondary lining structure arranged in the tunnel primary support structure. The tunnel primary support structure is provided with a support beam at the lower part on one side of the weak layer, a pile foundation is provided under the support beam, the upper end of the pile foundation is fixedly connected to the support beam, and a rigid anchor is anchored in the stable rock and soil body at the lower part of the other side of the tunnel primary support structure, and one end of the rigid anchor is fixedly connected to the support beam.

2. The horseshoe-shaped tunnel support structure according to claim 1 is characterized in that: The tunnel primary support structure includes an arch wall primary support structure and a tunnel bottom primary support structure, and the support beam is fixed directly below the tunnel bottom primary support structure.

3. The horseshoe-shaped tunnel support structure according to claim 1 is characterized in that: A longitudinal hidden beam is arranged inside the supporting beam, the upper end of the pile foundation is fixedly connected to the longitudinal hidden beam, and the lower end of the pile foundation is embedded in a stable rock and soil body.

4. The horseshoe-shaped tunnel support structure according to claim 1 is characterized in that: The two sides of the support beam are provided with a foundation pit primary support structure.

5. The horseshoe-shaped tunnel support structure according to claim 1 is characterized in that: The support beam adopts a reinforced concrete structure, and vertical main reinforcement of the support beam is arranged in the support beam. The upper end of the vertical main reinforcement of the support beam passes through the primary support structure of the tunnel bottom and then extends into the secondary lining structure.

6. The horseshoe-shaped tunnel support structure of the mining method according to claim 5 is characterized in that: One end of the rigid anchor is fixedly connected to the vertical main reinforcement of the joist.

7. The horseshoe-shaped tunnel support structure according to claim 3 is characterized in that: The pile foundation adopts a reinforced concrete structure. The pile foundation is provided with vertical main reinforcement of the pile body, and the upper end of the vertical main reinforcement of the pile body extends into the longitudinal hidden beam.

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