True triaxial experimental device and method capable of obtaining after-peak curve and residual strength of brittle rock

Abstract

Disclosed are a true triaxial experimental device and method capable of obtaining the after-peak curve and residual strength of brittle rock. According to the device, a rigid load application framework is arranged in the middle of a fixed high-rigidity counter-force framework, and large principal stress load application actuators indirectly apply loads to a rock sample in a pressure chamber through the rigid load application framework. The method comprises the steps of preparing and sealing the rock sample, and mounting a displacement sensor; mounting the sample, and accurately centering and clamping the sample in a displacement control manner to eliminate gaps; finely adjusting the displacement sensor to a a measuring range; sealing the pressure chamber, and filling the pressure chamber with hydraulic oil; synchronously applying minimum, intermediate and maximum principal stresses, applying axial loads to the rigid load application framework by the first and second maximum principal stress load application actuators, applying the maximum principal stress to the sample through the micro-deformation of the rigid load application framework, and simultaneously measuring the deformation of the sample; applying loads to the sample to make the sample enter an after-peak deformation stage and damaged; continuing applying loads to the sample until the residual strength is obtained; sequentially removing the maximum, intermediate and minimum principal stresses, disassembling the damaged rock sample, and saving experimental data.

Description

technical field [0001] The invention belongs to the technical field of rock mechanics experiments, in particular to a true triaxial experimental device and method capable of obtaining post-peak curves and residual strength of brittle rocks. Background technique [0002] Deep rock mass is the natural carrier of engineering objects such as underground mining, hydropower chamber excavation, oil and gas, and unconventional energy exploitation. Engineering excavation changes the initial stress state of the rock mass, and the initial stress state is in a true triaxial stress state (σ 1 >σ 2 >σ 3 ), this state change is specifically expressed as the minimum principal stress σ 3 Decrease and the maximum principal stress σ 1 When the stress in the rock reaches the strength of the rock, the rock will fail and enter the post-peak deformation stage, and the peak strength and failure form of the rock are still subject to the intermediate principal stress σ 2 However, the post-...

AI Technical Summary

Problems solved by technology

[0004] During the period from the 1960s to the 1980s, relevant international scholars developed a variety of rigid rock mechanics experimental equipment; however, these equipment can only perform uniaxial and conventional triaxial compression experiments, and some equipment does not have enough strain to To achieve the residual strength of the rock, some equipment cannot use axial compression deformation control loading throughout the process to obtain a stable post-peak curve

Images