Abstract: The study of propagation law of microseismic signal in layered rock mass is of great practical significance for realizing accurate source location. In natural rock mass, the propagation velocity of microseismic signal in rock strata is not only affected by its internal factors, namely the physical properties of rock itself, but also by external factors, such as geological structural plane, fault and goaf. Through laboratory experiments, the propagation law of microseismic signals in different strata and near mined-out areas was studied. The results show that the wave velocity decreases as the propagation distance increases, and the attenuation of the wave velocity is slower with higher rock density. The attenuation ratio of propagation velocity is bigger when microseismic signal goes through more structural planes. The attenuation of energy is consistent with that of the wave velocity. It takes longer for microseismic signals to pass through a goaf with a larger cross-sectional area, whereas, the larger the values of the physical properties such as the density and elastic modulus of the rock around the goaf, the less the wave velocity attenuation when the microseismic signal passes. Marginal spectrum analysis results show that faults have a stronger obstruction to micro-seismic signals with higher frequency.

Key words: rock formation, structural plane, wave velocity, energy, marginal spectrum