Testing method for determining stress and damage mechanism of columnar jointed rock mass

Abstract

The invention discloses a testing method for determining a stress and damage mechanism of a columnar jointed rock mass. The testing method comprises the following steps: 1) preparing cement mortar according to mechanical characteristics of an actual rock mass to prepare a regular hexagonal prism-shaped test sample; 2) splicing the regular hexagonal prism-shaped test samples to form a cuboid-shaped columnar jointed rock mass test sample model; curing, cutting and polishing to prepare cube-shaped columnar jointed rock mass test pieces with different inclined angles; 3) putting the columnar jointed rock mass test pieces into a rock rheometer; fixing the rock rheometer in the horizontal direction and slowly applying axial pressure until the test pieces are damaged; recording stress and strain data in a testing process; 4) processing recorded testing data to obtain a stress-strain relation of the columnar jointed rock mass, wherein the stress-strain relation reflects the stress and damage mechanism of the rock mass. According to the testing method disclosed by the invention, stress and damage conditions of the columnar jointed rock mass are demonstrated by a model testing method; the testing method has the advantages of low construction price, high simulation degree, simplicity in operation and the like.

Description

technical field [0001] The invention belongs to the field of rock mechanics and engineering, and relates to a method for rock mechanics test research, in particular to a test method for determining the stress and failure mechanism of columnar joint rock mass. Background technique [0002] In the southwestern region of our country, there are abundant water resources, and it is located at the junction of the first and second steps in our country. The drop is huge, and the water energy resources are abundant, which is suitable for the construction of large-scale water conservancy engineering facilities. However, the complex geological structure in the southwestern region restricts the construction of the project. The Baihetan Hydropower Station located in the lower reaches of the Jinsha River is the second largest hydropower station in China. Its diversion tunnel is built in the columnar joint rock mass belt, and its safety and stability are seriously threatened. [0003] As a ...

AI Technical Summary

Problems solved by technology

[0005] During the excavation and support construction of the columnar joint basalt cave section, the main geological problems occurred as follows: ① There are a large number of irregular longitudinal (parallel columns) and transverse (vertical columns) micro-cracks in the rock body, which are easy to form after excavation Unstable block structure; ②Poor anti-disturbance, the rock mass is easy to relax after unloading, resulting in local instability, relaxation deformation, falling off blocks, collapse and other adverse geological phenomena; ③Columnar joint rock mass not supported in time The relaxation and unloading damage will continue to occur, and the damage will continue to develop to the deep part of the rock mass; ④ There are different degrees of flaking in areas with high local in-situ stress, which endangers construction personnel.

[0006] In this regard, the usual practice of scientific researchers is to conduct simulation tests on site, but the huge amount of earthwork in hydraulic engineering restricts its feasibility; another method is to conduct indoor tests, but sampling, measurement, modeling, and testing are cumbersome. will affect the duration of the project

Images