Excavation Support Method for Asymmetric Squeeze Deformed Tunnel

Abstract

The invention relates to an excavation and support method of an asymmetric squeezing type deformation tunnel. The method includes the steps that firstly, wall rocks are divided into an upper-portion large deformation region, an upper-portion stress concentration region, a lower-portion large deformation region and a lower-portion stress concentration region according to the position relation between main stress and the wall rocks; secondly, a tunnel excavation plane is divided into a first region, a second region, a third region and a fourth region according to stress and deformation characteristics of the wall rocks; thirdly, the wall rocks which are not excavated in the upper-portion large deformation region are supported by a first advanced small pipe; fourthly, the first region is excavated, and the wall rocks corresponding to the first region are subject to overbreak according to a deformation allowance and positioning arcs. The excavation and support method of the asymmetric squeezing type deformation tunnel greatly reduces the supporting cost of the tunnel and greatly improves construction efficiency.

Description

technical field [0001] The invention relates to the field of geology, in particular to an excavation support method for an asymmetric extrusion-type deformation tunnel. Background technique [0002] Soft rock tunnels are characterized by weak surrounding rock, high in-situ stress, high pressure ratio, and significant radial deformation. They have poor self-stability, which can easily cause tunnel structure rupture and floor heaving, causing huge engineering hazards. At present, the large deformation treatment of soft rock tunnels at home and abroad is mostly the reinforcement technology of the surrounding rock. In summary, there are mainly support methods such as long anchor cable support, rigid-flexible support, release of ground stress, and advanced reinforcement for the surrounding rock. . These measures have been applied in the world for a long time, and have also been applied in domestic projects such as Guanjiao Tunnel, Wushaoling Tunnel, Jiazhuqing Tunnel, Yiwan Rail...

AI Technical Summary

Problems solved by technology

The traditional full-section strong support method increases the support cost, and the over-strong support control measures mean that the deformation of the surrounding rock is small, the structure is stressed, and a large number of support operations result in waste of resources and excessive construction time. , the deformation control of the surrounding rock is not coordinated, and the structure is prone to cracking and damage due to uneven stress

Therefore, at present, the asymmetric extrusion large deformation control of soft rock tunnels is basically in a blank state at home and abroad.

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