Dynamic test method for surrounding rock disturbed stress field during tunnel construction process

Abstract

The invention relates to a dynamic test method for the surrounding rock disturbed stress field during the tunnel construction process. The method includes the following steps of constructing an anteriorly arranged excavation body adjacent to a to-be-monitored tunnel, wherein the anteriorly arranged excavation body is provided with at least one monitoring space and the monitoring space is located in front of the excavating surface of the to-be-monitored tunnel; in the anteriorly arranged excavation body, arranging at least one monitoring drilling hole in front of the excavating surface of the to-be-monitored tunnel, wherein the monitoring drilling hole is substantially parallel to the excavating surface of the to-be-monitored tunnel; arranging a strain block at a measuring point inside the monitoring drilling hole, wherein the strain block is provided with a plurality of strain sensors for monitoring the three-dimensional strained condition of the measuring point; grouting into the drilling hole to drive the strain block to closely cling to the surrounding rock; during the tunnel excavation process, generating the disturbance deformation by the surrounding rock, transmitting displacement data signals monitored by the strain sensors to a monitor, and converting the displacement data into stress data by the monitor according to the elasticity modulus and the poisson 's ratio of the strain block. In this way, the three-dimensional strained condition of the measuring point can be obtained.

Description

technical field [0001] The invention relates to the field of testing surrounding rock disturbance stress field, in particular to a dynamic testing method for surrounding rock disturbance stress field during tunnel construction. Background technique [0002] In-situ stress of rock mass is also called initial stress of rock mass, absolute stress or in-situ stress in engineering circles. The in-situ stress of rock mass is a three-dimensional stress state, generally compressive stress. [0003] In the process of underground engineering construction, engineering excavation will lead to changes in the original stress field in the rock mass, that is, stress disturbances. However, during the excavation process of tunnels, especially soft rock tunnels, certain stress disturbance areas will inevitably be generated, and their distribution characteristics and evolution rules are important basis for the optimization of tunnel support parameters and long-term safety evaluation. The chan...

AI Technical Summary

Problems solved by technology

This has the following problems: a. What is actually measured is the strain value of the strain gauge carrier. Although the strain gauge carrier exists in the surrounding rock, there is a difference between the strain value of the strain gauge carrier and the real strain value of the surrounding rock, that is: The measured strain value is not the real strain value of the surrounding rock, and the change of the real surrounding rock stress cannot be obtained by using this strain value combined with the elastic modulus and Poisson's ratio of the surrounding rock itself; b. The elastic modulus and Poisson's ratio of the surrounding rock It is difficult to accurately determine the ratio, which further leads to inaccurate final measurement results

[0008] In addition, another type of three-dimensional stress testing element focuses on how to directly measure the surrounding rock stress. This type of testing element has a complex structure, high cost, inconvenient construction, easy damage, and inaccurate measurement results.

Images