A Method for Estimating Ground Stress in Soft Rock in Fault Fracture Zone

Abstract

The invention relates to a method for estimating the ground stress of soft rock in a fault fracture zone, comprising: obtaining the ground stress test results of three principal stresses in the hard rock area to determine the stress matrix of the original coordinate system in the hard rock area; Transform the stress matrix of the coordinate system into the stress matrix of the geodetic coordinate system in the hard rock area; convert the stress matrix of the geodetic coordinate system in the hard rock area into the stress matrix of the fault coordinate system in the hard rock area; transform the fault coordinate system of the hard rock area The stress matrix of the soft rock area is converted into the stress matrix of the fault coordinate system in the soft rock area; the stress matrix of the fault coordinate system in the soft rock area is converted into the stress matrix of the geodetic coordinate system in the soft rock area; The matrix is ​​transformed into a stress matrix in the tunnel coordinate system for soft rock regions. The stress estimation method is based on the in-situ stress test results of the complete rock mass to estimate the in-situ stress of the soft rock in the fault fracture zone, so that the large deformation prediction results can be well consistent with the measured results.

Description

technical field [0001] The invention relates to the technical field of civil engineering, in particular to a method for estimating the ground stress of soft rock in a fault fracture zone. Background technique [0002] The soft rock in the fault fracture zone of deep-buried long tunnels is prone to large deformation disasters. In-situ stress is an important parameter for the classification and prediction of large deformation disasters, and its reasonable value is very important. At present, the commonly used in-situ stress testing methods include hydraulic fracturing and stress relief methods. The in-situ stress tests of the above two methods require relatively intact rocks, especially the stress relief method also requires drilling and coring for the integrity of the rock mass. higher. [0003] Therefore, most of the existing in-situ stress tests are carried out in the complete rock mass, and the in-situ stress test results are difficult to reflect the real in-situ stress c...

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Problems solved by technology

[0004] This application provides a method for estimating the in-situ stress of soft rock in the fault fracture zone, which solves the problem that the in-situ stress tests of existing deep-buried long tunnels are mostly carried out in intact rock mass, and the in-situ stress test results are difficult to reflect the reality of the soft rock in the fault fracture zone. In-situ stress conditions, resulting in a large difference between the large deformation prediction results and the actual measurement results, realized the technical effect of estimating the in-situ stress of soft rock in the fault fracture zone based on the in-situ stress test results of the complete rock mass

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