Peridynamic modelling of blasting induced rock fractures

Abstract

This paper presents a peridynamics-based computational approach for modelling blasting induced rock fractures. A new non-ordinary state-based peridynamics approach is proposed in conjunction with a Johnson-Holmquist (JH2) constitutive model to consider the pressure dependency, strain rate effect, and viscoplasticity of rocks under blasting loads. The fracturing process in a rock is assessed based on both the JH2 damage model and a tension failure model. The former evaluates the material response pertaining to excessive plastic strain and the latter is used to gauge failure based on tensile stress in consideration of strain rate effect. Detonation in the explosives is simulated using updated Lagrangian peridynamics in conjunction with Jones-Wilkins-Lee (JWL) equation of state. Simulations of single-hole blasting in granite rock are presented and compared with experimental records. The proposed approach is shown to capture reasonably well the plastic material failure surrounding the borehole as well as the tensile cracks on both radial and circumferential directions. Further sensitivity studies indicate that the intact strength parameters in the JH2 model and the tensile strength of material play a vital role in producing the obtained fracture patterns and should hereby be selected with care. The presented computational approach offers a rigorous basis for future development of versatile, multi-physics-integrated computational framework on rock blasting simulations.