Acoustic response characteristics and engineering significance of loaded rock during failure process

During the gestation and development process of mine disasters, the variation of rock mass stress is often accompanied, then causing rock deformation and destruction and the acoustic feature of surrounding rock will be changed. Wave velocity variation characteristics of rock could have an effect on geological disaster forecast. The rock samples derive from Jincheng coal mine area. This paper collects acoustic wave pulse signal through rock mechanics loading system and acoustic wave test system under single axle load failure process, picks the first arrival time of pulse signal and deal with the test data by using the self-developing “pickup module”. The research results show that the rock mechanics characteristics and wave velocity variation characteristics of coal measure strata have large difference in different area, wave velocity variation can be divided into 5 stages, that is “upper concave-linear increase-sudden drop and rise-level fluctuations-step drop”, during loading process, brittle rock is short of level fluctuations stage. Wave velocity appears drop point of shock type when the load is （65.67%-86.75%）σmax. The drop point of wave velocity also is the volumetric dilatancy point during rock deformation and fracture process. The increase amplitude of wave velocity has large difference during loading process for the rock in different area. The wave velocity responding mechanism of different stages has different engineering significance during load process, which can provide references for the geological disasters prevention of coal mine.