Study on variation characteristics of wave velocity in whole process ofrock uniaxial loading failure

Mechanical properties of rock is the basis of the acoustic wave monitoring technology. The stability and development of rocks can be studied by observing the propagation process of sound waves inside the rock. In order to understand the variation of acoustic waves in the medium propagation process under the rock load of No. 2 Zhaozhuang Mine, the uniaxial loading test adopted the rock mechanics experimental machine and the acoustic testing system to test the sandstone, mudstone and limestone of the typical strata of No.2 Zhaozhuang Mine in Jincheng under the condition of uniaxial loading, different loading methods were used to compare and obtain the applicability of the method. Then, the observed acoustic waves were used to study the development of rock fissures, the longitudinal and transverse wave velocities of different lithologies and the changes of stress-strain processes. The test results show that the displacement control method can obtain the full stress-strain curve better. During the loading process, the sample velocity is linear and the wave velocity increases linearly; when the stress peak is reached, the specimen is damaged and the bearing capacity is reduced, the softening characteristics appear, and the stress and the wave velocity change nonlinearly. The variation trend of wave velocity is basically consistent with the stress-strain curve, and different wave velocity response characteristics occur in different stress-strain stages. Through the test observation of the acoustic wave loading characteristics of rock loading, the stability of rock mass or the development of internal fractures can be predicted, which has important guiding significance for the response characteristics analysis of acoustic emission monitoring technology.