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

Abstract

A true triaxial experimental device and method capable of obtaining post-peak curves and residual strengths of brittle rocks. A rigid loading frame is provided in the middle of the fixed high-rigidity reaction frame of the device, and the large principal stress loading actuator is indirectly controlled by the rigid loading frame. The rock sample in the pressure chamber is loaded. The method is as follows: prepare and seal the rock sample, install the displacement sensor; install the sample, accurately center and clamp the sample in the displacement control mode to eliminate the gap; fine-tune the displacement sensor to the range; close the pressure chamber and fill it with hydraulic oil; Apply the minimum, intermediate and maximum principal stresses, and apply axial loads to the rigid loading frame by the first and second maximum principal stress loading actuators, apply the maximum principal stress to the sample through the micro-deformation of the rigid loading frame, and measure the sample at the same time Deformation; the loaded sample enters the post-peak deformation stage and fails; continue to load the sample to the residual strength; unload the maximum, intermediate, and minimum principal stresses in sequence, remove the damaged rock sample, and save the 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-...

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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

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