The Research Of High-stressed Rocks Failure Mechanism Under Lateral Point Disturbance

At present, the failure mechanism of local high stress rock under lateral disturbance is still a lack of research. In this paper, the lateral disturbance test under high stress was carried out to research the failure mechanism of rock and the acoustic emission feature when the role of different static load condition by usind the true triaxial electro-hydraulic servo-controlled test system. The test results is verified by the numerical simulation using software PFC3D, in addition, the rock crack development and the failure mechanism is also analyzed when the role of the different disturbance amplitude under the condition of high stress. The results can provide a theoretical and technical support, in revealling the mechanism of rock burst and the improvement of the efficiency of the deep drilling. In this paper,the main contents and results are as follows:1. With The true triaxial electro-hydraulic servo-controlled test system, tests on100mm×100mm×100mm granite specimens under lateral disturbance and vertical static stresses have been conducted. The PCI-2acoustic emission (AE) system was used to pick up AE signals. It’s found that the peak AE energy event usually happens at the unloading section of the disturbance stress. The peak AE energy event tends to happen earlier and more frequently with the increase of the static stresses.2. Wave velocities at different positions were used to evaluate the damage distribution of the specimen at different loading conditions. RA values were also used to investigate the failure mechanism of specimens. The results indicate general failure patterns of specimens:when the static stress is low, only few shear cracks are triggered and small shear failure zone can be observed at the direct contact zone of the disturbance load. When the static stress is high, shear cracks and tensile cracks are both activated and the proliferation of tensile cracks results in the structural failure of specimens finally.3. The rock damage test of the same disturbance under different static load is simulated by PFC3D which results are consistent with the test results. At the same time, the rock failure test of the same static load under different dynamic disturbanc is also simulated. The results show that the crack growth rate, the total of the crack is proportional to the disturbance amplitude when the role of high stress rock under the action of lateral disturbance. The crack extension in depth increase while increasing disturbance amplitude, but the cracks mainly distributed at the side of the sample by the disturbance, fracture penetrability is not strong as well. At the same time, improve the disturbance amplitude can increase the degree of disturbance at the end of fracture.4. The summary of the test and simulation results indicate that the increase of power perturbation amplitude can help to improve the effect of disturbance of broken rock, but the effect is limited; The rock fragmentation effect of persistent disturbances is better than the single disturbance, however, the dynamic rock fragmentation effect has a remarkable achievement with the improvement of static load.