Support method of large-section soft rock large-deformation tunnel

Abstract

A supporting method of a large-section soft rock large-deformation tunnel comprises the steps that after excavation is conducted by one footage, concrete is initially sprayed, then hole drilling is conducted, first restraining rods are fed into holes and grouted, and thus an upper initial lining support is formed; under the upper initial lining support, middle steps are excavated on the two sidesin a staggered mode, and then concrete is initially sprayed; after hole drilling, second restraining rods are fed into holes, concrete is re-sprayed to the designed thickness; lower steps are excavated on the two sides in a staggered mode, and then concrete is initially sprayed; after drilling, third restraining rods are fed into holes, the left sides and the right sides of the lower steps are backfilled; and a middle step reserved core soil part and a lower step reserved core soil part are excavated, then, an inverted arch is excavated, and the next cycle of construction is conducted till thetunnel breaks through. According to the support method of the large-section soft rock large-deformation tunnel, the support type is converted from internal supporting into external supporting, thus the space in the tunnel is saved, the safety and durability of the support structure are guaranteed, the safer, more economic and more durable effects and high operability are achieved while large deformation of the tunnel is effectively controlled, and the construction period is effectively shortened.

Description

technical field [0001] The invention relates to the field of tunnel engineering, in particular to a support method for large-section soft rock large-deformation tunnels. Background technique [0002] my country is a country with many mountains and hills, among which mountains and hills account for 69% of the country's land area. The construction of transportation infrastructure will also develop rapidly, and a large number of soft loose surrounding rock tunnels will inevitably be encountered during the construction of highways and railways. When tunnels are built in soft and loose strata, the self-stability of the surrounding rock is poor, and slumping and traction deformation are prone to occur, and the deformation is large, lasting for a long time, and rheological characteristics are obvious. The initial support structure of the tunnel is prone to problems such as cracking, falling blocks, steel frame distortion, breaking and encroachment under the action of large extrusi...

AI Technical Summary

Problems solved by technology

[0004] (1) The project cost is high, the process is cumbersome, the progress is slow, and the construction period is extended;

[0005] (2) The effect of controlling large deformation of soft rock is general or even ineffective;

[0006] (3) The secondary lining is often constructed when the deformation of the initial support structure has not converged, and the stress on the secondary lining is relatively large, so the reliability, safety and durability of the tunnel structure cannot be guaranteed;

[0007] (4) Without considering the stability of the initial support structure, blindly strengthening the strength and stiffness of the initial lining, the support effect is poor, and the economic efficiency of the tunnel project is poor

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