Tomography of the dynamic stress coefficient for stress wave prediction in sedimentary rock layer under the mining additional stress

Abstract

In this study, the tomography of dynamic stress coefficient (TDSC) was established based on a mechanical model of stress wave propagation in bedding planes and a mathematical model of the stress wave attenuation in rock masses. The reliability of the TDSC was verified by a linear bedding plane model and field monitoring. Generally, the TDSC in the dynamic stress propagation of bedding planes increases with the following conditions: (1) the increase of the normal stiffness of the bedding plane, (2) the increase of the incident angle of the stress wave, (3) the decrease of the incident frequency of the stress wave, or (4) the growth of three ratios (the ratios of rock densities, elastic moduli, and the Poisson’s ratios) of rocks on either side of bedding planes. The additional stress weakens TDSC linearly and slowly during the stress wave propagation in bedding planes, and the weakening effect increases with the growth of the three ratios. Besides, the TDSC decreases exponentially in the rock mass as propagation distance increases. In a field case, the TDSC decreases significantly as vertical and horizontal distances increase and its wave range increases as vertical distance increases in the sedimentary rock layers.