Experimental and numerical analyses on the effect of stiffness on bedded sandstone strain burst with varying dip angle

Strain burst violence is related to the stiffness ratio (SR) between environmental and bursting rock masses. Strain burst tests on dolomite specimens with different system stiffnesses and bedded sandstone with four different dip angles as well as numerical analyses of strain burst with different structures are carried out to study the effect of stiffness on strain burst. Results indicate that strain burst intensity is larger in a more flexible system environment, and lower SR corresponds to a larger probability of strain burst. Additionally, with increasing SR, the failure mode becomes more stable, and the influence of the structures on failure mode vanishes gradually. For the lowest SR, the strain energy densities (SEDs) from the surrounding rock are lower for steep structures, while flatter structures correspond to higher SED. Moreover, for vertical and horizontal structures, variation in SED with SR is more sensitive; however, for steep and medium discontinuities, the sensitivity is lower.