Dayao Copper Mine Sandstone Mechanical Damage And Acoustic Emission Characteristics And Laws Of Fractal Theory

Rock is a typical non-heterogeneous material in nature, and its mechanical properties are anisotropic, complex and changing in the process of deformation and failure initiation. It is bearing the internal micro cracks, expanding, loss of carrying capacity through until the final formation of a large number of macroscopic crack. Acoustic emission technology is the study of an acoustic rock damage law. Through the analysis and research of rock acoustic emission signal parameters, you can infer that rock internal nature from the change process, and inversion of the failure mechanism of rock. Fractal geometry is the study on the statistical significance of self-similarity of a branch of mathematics, it contains an important characteristic of fractal dimension, which is a rare powerful tool used to study a number of seemingly chaotic complex physical phenomena. A large number of experiments have proved that, rock acoustic emission sequence, whether in space or time have fractal characteristics. GP algorithm used in this paper to get the rock acoustic emission time series correlation dimension, and to study their evolution in the process of rock failure. In this paper, we use the uniaxial strain loading mode compression test and cyclic loading test to study the sandstone’s failure characteristics and acoustic emission characteristics and characteristic parameters of acoustic emission ringing count for the fractal time series analysis. Main content is as follows:(1) Both red sandstone and gray sandstone rock samples taken form Dayao Copper were prepared cylindrical specimens. A rate of about0.1mm/min to destroy and the whole process of uniaxial compression tests have been carried out. And at the same rate for the cap of70%of the peak stress and corresponding strain, lower limit corresponding to the peak stress strain30%of the single cyclic loading test. Analysis of the rock damage characteristics in the process of loading.(2)Synchronous records the acoustic emission signal in the experiment, the ringing count of the test piece, the event rate and the energy of the acoustic emission characteristic parameters, such as the relationship between the stress are analyzed, acoustic emission rules of rock are preliminarily reached.(3)Introduce the fractal theory and fractal dimension algorithms, using the the MATLAB calculation software programming to calculate the correlation dimension, the evolution of the correlation dimension of rock acoustic emission in the process of loading time series is analyzed.(4) Through the analysis of the relationship between the correlation dimension and the stress and time, and study the variation of the correlation dimension in different stress, on the basis of analysis to determine a time of acoustic emission sequence correlation dimension for precursory research reference value of rock destruction.