Research on Acoustic Emission of Deep Buried Metamorphic Limestone under Uniaxial Loading Test

Deeply excavating the parameters of acoustic emission has great significance to research the characteristics of rock damage evolution,to understand the mechanism of rock fracture,and to predict the instability of rock mass and so on.Through the uniaxial compression with acoustic emission test,the damage and fracture mechanism of metamorphic limestone was studied deeply.The study shows that:The metamorphic limestone has significant hard and brittle characteristic,and during the test,the number of AE events,ringing count and energy showed a similar change trend of initial small-slow growthrapid growth-slow growth;the AE event space and time positioning results show that in the early stage of experimental loading,there were fewer AE events in the rock sample,and with the increase of load,the AE event first accumulated at the top of the rock sample and then gradually extended to the middle until it passed through the bottom of the sample,and the AE positioning results were consistent with the failure characteristics of rock sample.Through the AE monitoring technology,we can research the whole process of crack initiation,nucleation,expansion and interchange of the rock sample under loading,and it is of great significance to study the whole process of damage and failure of rock.