Modified Model of Sound Velocity with Different Saturation in Fractured Sandstone

Abstract

The hazards of surrounding rock sheeting, collapse and rock explosion during the excavation of underground projects can be regarded as the macroscopic dynamics of the evolutionary development of their internal fractures, mostly accompanied by acoustic emission phenomena. The application of acoustic emission detection technology can quickly determine the existence of fissures in the surrounding rock and predict their approximate location and spatial spread. Therefore, considering the effect of fissures on the sound velocity propagation law. In this work, experiments on the identification of acoustic emission signal paths in solid media with different void states are carried out, and the path propagation law of acoustic emission signals is explored and studied. A comparative analysis of acoustic emission source localization in fractured sandstone with different sensor arrays at different saturation levels was carried out using water as the coupling agent. The acoustic emission source 3D localization results are optimized by correcting the time difference model. The results show that the acoustic emission signal propagation conforms to the shortest distance principle. In the localization of 3D cylindrical AE sources, it is suitable to select a combined array of spatial tetrahedral sensors for better localization. As the saturation increases the positioning effect gets closer to the actual value. The sound source localization effect of the sound velocity correction model based on the time difference method is closer to the actual lead break position. In actual engineering, water as a benign coupling agent can better improve the accuracy of AE source localization in fracture-containing sandstone, which can provide some guiding suggestions for related engineering.