Study on Propagation Characteristics of Elastic Waves in Coal Measure Strata with Small Faults

The coal seam and surrounding rock around the small fault are equivalent to the fracture anisotropy medium, and the equivalent medium model of the coal measure strata with small fault is established. Based on this, the anisotropic elastic wave equation of fracture was deduced by using Husdon fracture medium theory and the method of finite element numerical simulation was used. Rick wavelet selected as the source. The simulation of the propagation of elastic waves in the coal measure strata with small faults is carried out by using COMSOL finite element software. The influence of small faults on elastic wave propagation in coal seam is analyzed. It is concluded that as the frequency of the source increases, the displacement ratio of the two particles gradually decreases, that is, the vibration amplitude of the particles tends to be gentle. With the increase of the small fault interval, the energy ratio of the elastic wave in the coal seam before and after the small fault decreases approximately linearly.