Numerical simulation of uniaxial compression tests on layered rock specimens using the discrete element method

Abstract

In this paper, uniaxial compression tests on layered rock specimens are numerically modelled using the discrete element method to investigate the effect of a soft interlayer on the strength and deformation of rock specimens. For these simulations, the thickness and dip angle of the soft interlayer were varied. Thirty-five numerical models for different cases were established after calibrating the micro-mechanical parameters of the hard and soft rock materials. The computational results were analysed in terms of three aspects: the stress–strain curves, micro-crack propagation patterns, and particle velocity fields. The stress–strain curves indicate that increasing the thickness and dip angle of the soft interlayer causes the peak stress and ultimate strain to drop by up to 42% and 34%, respectively. The thickness of the soft interlayer has a greater influence than that of the soft interlayer dip angle on the uniaxial mechanical behaviour of the rock specimen. Additionally, crack propagation patterns and particle motion in the layered rock models indicate that the cracks develop preferentially along the soft interlayer and that the notable failure features of the layered rock models are stepped failure modes that occur at greater dip angles.