Triaxial test pressure chamber capable of simulating unloading and supporting of underground caverns and tunnel excavation

Abstract

A triaxial test pressure chamber capable of simulating unloading and supporting of underground caverns and tunnel excavation comprises a triaxial pressure chamber body which is used for loading samples and providing confining pressure and axial pressure. An inner side hydraulic sleeve is arranged in an inner hole channel of the sample, and the inner side hydraulic sleeve is used for providing inner side variable confining pressure and simulating stress change in the excavation and reinforcement process. An outer side hydraulic sleeve is arranged on the outer side of the sample, and the outer side hydraulic sleeve is used for providing outer side confining pressure and simulating a ground stress field where the underground rock mass is located. A base is in butt joint with a connector of the inner side hydraulic sleeve, hydraulic oil enters the connector of the inner side hydraulic sleeve through an oil inlet of the base, and inner side variable confining pressure is provided. An axialdisplacement sensor is located at the top of the triaxial pressure chamber body, and the axial displacement sensor is used for measuring axial deformation in a triaxial test. The method is used for simulating the unloading and supporting conditions of on-site underground caverns and tunnel excavation, and the mechanical characteristics and the damage characteristics of tunnel surrounding rock in the excavation unloading and reinforcing process can be mastered more accurately.

Description

technical field [0001] The invention belongs to the field of geotechnical engineering mechanics test instruments, and relates to a triaxial test pressure chamber capable of simulating the excavation, unloading and support of underground caverns and tunnels. Background technique [0002] In order to study the physical and mechanical properties of rock mass under natural conditions, it is often necessary to simulate the natural environment of the rock mass. Although the in-situ test can restore its environment, it is difficult to implement. Some factors cannot be controlled, so it is necessary to simulate the environment in which the rock mass is located in the laboratory. [0003] The excavation of the underground cavern destroys the original stress balance condition, causes the stress redistribution of the surrounding rock mass, and stress concentration occurs around the cavern. At this time, if the stress field at each point of the cave wall does not exceed the critical va...

AI Technical Summary

Problems solved by technology

In this test method, the rock sample is solid, and the loading and unloading of lateral stress can simulate the unloading of on-site slope excavation, but it cannot simulate the excavation and unloading of underground caverns and tunnels.

Existing various triaxial pressure chambers can only simulate the excavation and unloading of slope or foundation pit rock mass, but cannot simulate the excavation, unloading and support of underground caverns

The main reason is that the slope or foundation pit is the excavation of surface rock and soil. During the test, the stress change process of excavation and unloading can be simulated by controlling the lateral stress loading and unloading of the sample; It is carried out inside the body, which is quite different from the stress path of the conventional triaxial unloading test

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