394 / 2022-05-04 10:07:07

Acoustic emission (AE) characteristics of rock under the disturbance stress paths

Acoustic emission,disturbance mode,disturbance stress path

Resource Development and Utilization of Underground Space > 1. Foundation of Deep Rock Mechanics

The deformation and failure of rock mass is affected to a great extent by the disturbance stress caused by the excavation activities, especially in the situation of the deep underground. The characteristics of the disturbed rock are the key issue for both academic and engineering fields. In this paper, the red sandstone specimens are employed to conduct a series of disturbance stress path tests by MTS815 Flex Test GT mechanical test system. Meanwhile, the AE signals generated during the tests are recorded by PCI-2 AE system. Then, the AE temporal-spatial distribution is compared under the disturbance stress paths (hydrostatic stress stage, initial loading-unloading stage, and disturbance stage) and the 3 disturbance modes (low disturbance mode mid disturbance mode, and high disturbance mode) to investigate the influence of the different disturbance stress modes on the damage of rock specimens under the confining pressure of 12.5MPa. During the hydrostatic stress stage, under the 12.5MPa, it can be found that there are a rapid stage and a moderate stage of AE energy and AE count. During the initial loading-unloading stage, it can be seen that the evolution of AE temporal-spatial distribution is inconspicuous. During the disturbance stage, the evolution of the AE temporal-spatial distribution of the specimens is sensitive to the disturbance modes under the 12.5MPa. And the damage inside the rock specimens from serious to mild in proper order are: the high disturbance mode, medium disturbance mode, and low disturbance mode.