Triaxial stress simulation method for water storage roadways in abandoned mine pumped storage

A triaxial stress simulation method for water storage roadways in abandoned mine pumped storage, comprising following steps in sequence:

• a, preparing a cube sample as a rock sample, and carrying out an uniaxial compression test on the rock sample to obtain a maximum failure load of the rock sample;
• b, installing another rock sample in a true triaxial dynamic loading system, wherein the true triaxial dynamic loading system comprises a workbench, a main frame, a confining chamber, a vertical loading unit, a horizontal loading unit, a longitudinal loading unit, a lifting device, and a feeding and discharging platform;
• the vertical loading unit comprises an impact transmission rod;
• the longitudinal loading unit comprises a front loading oil cylinder, a rear loading oil cylinder, a front loading head, and a rear loading head;
• the front loading head and the rear loading head are arranged opposite each other from front to rear inside the confining chamber through a longitudinal loading rod, the front loading oil cylinder and the rear loading oil cylinder are symmetrically arranged on a front side and a rear side of the main frame through a rotating arm, and static loads are synchronously applied to the front loading head and the rear loading head;
• a square groove is formed on an end face of the front loading head, and a water channel is arranged inside the longitudinal loading rod connected to the front loading head, the water channel is connected to a water supply device for providing high-pressure water into the square groove;
• c. applying a preload to fix the rock sample in the true triaxial dynamic loading system;
• then applying a maximum principal stress σ1, an intermediate principal stress σ2, and a minimum principal stress σ3 to the rock sample through the vertical loading unit, the horizontal loading unit, and longitudinal loading unit, respectively;
• during an initial loading process, the maximum principal stress σ1 and the intermediate principal stress σ2 are 50% of the maximum failure load specified in step a;
• the minimum principal stress σ3 is 10% of the maximum failure load specified in step a;
• after the loading stabilizes, the maximum principal stress σ1 is adjusted to 80% of the maximum failure load specified in step a;
• d, keeping the maximum principal stress σ1, the intermediate principal stress σ2 and the minimum principal stress σ3 unchanged, applying single-sided dynamic water pressure to the rock sample through the front loading head, and simultaneously applying dynamic load to the rock sample through the impact transmission rod;
• e. observing and recording;
• ending the test when the rock sample in the true triaxial dynamic loading system has failed, recording obtained stress-strain curve data, strain-time curve data, and water pressure-time curve data, and observing a failure mode of the rock sample;
• f, combined with theoretical knowledge, obtaining the failure strength and failure form of the surrounding rock of water storage roadways in abandoned mine pumped storage under different depths and water pressures.