Method for determining deformation allowance of high-ground-stress soft surrounding rock tunnel in excavation

Abstract

The invention discloses a method for determining the deformation allowance of a high-ground-stress soft surrounding rock tunnel in excavation, which comprises the following steps: 1, excavation of a test section, wherein the test section of the constructed soft surrounding rock tunnel is excavated from back to front along the longitudinal extension direction of the tunnel; and in the process of excavating, a tunnel hole formed by excavating is subjected to preliminary bracing from back to front, and then a preliminary bracing structure of the tunnel hole is obtained; 2, deformation monitoring, wherein crown settlement values and horizontal clearance convergence values on N tunnel monitoring cross-sections in the test section are respectively monitored, and then N sets of deformation monitoring data respectively corresponding to the N tunnel monitoring cross-sections are obtained; 3, determination on a deformation allowance range based on an assurance rate, wherein the determined deformation allowance range includes a deformation allowance range of an arch of the tunnel and a deformation allowance range of a side wall of the tunnel; and 4, determination of deformation allowance. The method disclosed by the invention is simple in steps, convenient to implement, low in invested cost and good in using effect, and can effectively solve the problem of determining the deformation allowance of the high-ground-stress soft surrounding rock tunnel.

Description

technical field [0001] The invention belongs to the technical field of tunnel excavation construction, and in particular relates to a method for determining the reserved deformation amount for excavation of a tunnel with high ground stress and weak surrounding rock. Background technique [0002] Tunnel excavation will inevitably lead to the redistribution of the original stress of the surrounding rock. The mechanical behavior of the stress redistribution of the entire surrounding rock can be generalized as the following process: balance. "Looseness" and "looseness" are two completely different concepts in describing the process of stress redistribution, and the manifestations of surrounding rock loads in these two processes are also different. The load generated in the "relaxation" stage is called "deformation pressure". At this time, the reduction of the stress level of the surrounding rock and the deformation of the surrounding rock coexist. From the perspective of rock m...

AI Technical Summary

Problems solved by technology

[0014] The technical problem to be solved by the present invention is to provide a method for determining the amount of reserved deformation for excavation of tunnels with high ground stress and weak surrounding rocks in view of the deficiencies in the above-mentioned prior art. , which can effectively solve the problem of determining the reserved deformation of tunnels with high ground stress and weak surrounding rock

Images