Stability evaluation of excavated rockmass in mines based on microseismic monitoring

Crack damage evolution mechanism of surrounding rock in deep mines was analyzed under excavation disturbance based on the results of microseismic monitoring data recorded and numerical simulation using realistic failure process analysis(RFPA) approach.The qualitative relations between microseismic variable values estimated from mine microseismic monitoring systems and the stress estimates provided by numerical models were explored.The research results show that microseismic monitoring system can effectively identify evolution mechanism the microcracks of surrounding rock and help to locate potential instability area of rockmass.The generation of potentially instability area insurrounding rock of No.3363 stope was mainly due to existed high water pressure aquifer in overlying rock strata of stope.The stress concentration zone was formed between aquifer and goaf under the effect of high water pressure and excavation disturbance,induced micro-fractures initiation,growth and expansion in deep rock masses,and formed potential instability area.There are good corresponding relations between microseismic variable values(cumulative events number,cumulative energy,and cumulative stress drop) estimated from mine microseismic monitoring systems and the stress estimates provided by numerical models.The shift of high stress area can be described based on tempo-spatial distribution regularity of microseismic events.It was possible by using microseismic variable values to quantitative analysis of the stress state of different regions.The research results provide important the basis for understanding instability failure mechanism of deep rock mass and microseismic activity law in complex geologic condition and be used to eventually impact both short-and long-term mine design decisions.