Theoretical study for induced seismic wave propagation across rock masses during underground exploitation

Abstract

During underground energy and resource exploitation, seismicity is unavoidably triggered and may cause potential hazard in civil engineering. Hence, induced seismic wave propagation across rock masses plays a crucial role in geophysics, mining and geothermal energy exploitation. The upper rock mass commonly consists of multiple layers with different depths and different distributions of joints. Each layered rock mass usually influences wave propagation and results in the time delay and amplitude attenuation when an incident wave impinges on the rock mass. At large scale, the rock mass can be treated as an equivalent continuous medium. The equation for wave propagation across a rock mass is first derived when the rock mass is equivalent as a viscoelastic medium. The seismic quality factor is taken into account. Next, considering that joints dominate the mechanical properties of rock mass, the relation between the seismic quality factor and the joint parameters such as joint distribution density and stiffness is analyzed. Then, the equation of seismic wave propagation across layered rock masses is derived. Finally, the parameter study about the effects of the character of layered rock masses and the frequency of induced seismic wave on the transmission coefficients is discussed.