Primary support construction for shallow-buried extra-large section tunnel crossing highway underneath in uneven strata

Abstract

The invention discloses a primary support construction for a shallow-buried extra-large section tunnel crossing a highway underneath in uneven strata, which aims to effectively control the settlement of tunnel construction and the ground settlement. The primary support construction comprises an advanced support structure and a primary support structure, wherein the advanced support structure is formed by combining external big pipe sheds (11) and internal big pipe sheds (12) which are radially arranged at intervals; and the primary support structure is formed by combining an arch external support layer (21) and a whole-ring internal support layer (22) which are formed by spraying concrete, and the side wall section of the primary support structure is distributed with side wall system anchor rods (20). The primary support construction has the advantages of effectively reducing the influence of excavation deformation on the ground, improving the stress of the primary support, strengthening the stability of soil body, effectively solving the technical problem of big section loess tunnel construction, controlling the settlement value of the tunnel construction and the ground settlement value within 30 mm, and ensuring the safety of the tunnel construction and highway operation.

Description

technical field [0001] The invention relates to a high-speed railway tunnel, in particular to an initial support structure for a tunnel with a super large cross-section buried shallowly and crossing an expressway with loess at the arch and rock formations below the arch. Background technique [0002] Zhengzhou-Xi'an Railway Passenger Dedicated Line, with a total length of 458.8km, is the first railway passenger dedicated line newly built in the loess area in my country with an operating speed of 350km / h. There are a total of 38 tunnels on the whole line, with a total length of about 77km, of which the loess tunnel accounts for 50km of the total length of the tunnel. The ballastless track is laid in the passenger dedicated line tunnel, which requires a high degree of smoothness of the line in the tunnel. The post-construction settlement requirement is not greater than 15mm, and the differential settlement between different structures should not be greater than 5mm. The settle...

AI Technical Summary

Problems solved by technology

[0006] The beneficial effect of the present invention is that the use of double-layer large pipe shed advance support can increase the rigidity of the pipe shed, reduce the distance between the pipe sheds, avoid the spalling of the soil between the pipes, and effectively reduce the impact of excavation deformation on the surface; The anchor rod of the wall system improves the stress of the initial support and enhances the stability of the soil. The outer support layer of the arch part and the inner support layer of the full ring are combined to form the outer lining of the tunnel, which enhances the rigidity of the initial support and the ability to resist deformation; effectively It solves the technical problems of large-section loess tunnel construction, can control the settlement value of tunnel construction and surface settlement within 30mm, and ensures the safety of tunnel construction and road operation

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