EXPERIMENTAL INVESTIGATION OF THE ACOUSTICS EMISSION CHARACTERISTICS OF TWO TYPES OF BRITTLE ROCKS UNDER UNIAXIAL COMPRESSION

This paper focuses on the detailed acoustic emission characteristics of the two different types of the brittle rocks. They are granite and sandstone. Through the uniaxial compression test, the acoustic emission signals during the failure process of the granite and sandstone specimens are recorded. The data analyses cover the mechanical responses and acoustic emission characteristics. The following acoustic emission parameters are used:accumulative AE count, accumulative AE energy, AF, RA, and b values. The research outcomes are as follows. (1) The deformation and strength parameters of the rock specimens are obtained and the parameter variabilities are analyzed. (2) The accumulative AE count and accumulative AE energy are influenced by the bond strength of the grains and uniformity of the rock specimens. (3) It needs to be further investigated that whether the AF and RA values can be used to differentiate the tensile and shear cracks in rocks and the threshold of AF and RA values of rocks if they can be used. (4) Micro-crack activities are still dominant when the sandstone specimen is approaching the peak stress. This paper obtains some important features of the brittle rock specimens under uniaxial conditions, which provides a good start for the future research work.