Combined Viscoplasticity‑Embedded Discontinuity Model for 3D Description of Rock Failure Under Dynamic Loading

This paper presents a combined viscoplasticity-embedded discontinuity model for 3D analyses of rock failure processes under dynamic loading. Capabilities of a rate-dependent embedded discontinuity model, implemented with the linear tetrahedral element, for mode I (tension) loading induced fractures is extended to compressive (shear) failure description by viscoplastic softening model with the Drucker–Prager yield criterion. The return mapping update formulas are derived for the corner plasticity case exploiting the consistency conditions for both models simultaneously. The model performance is demonstrated in 3D numerical simulations of uniaxial tension and compression test on a heterogeneous rock at various loading rates. These simulations corroborate the conception that the rate sensitivity of rock is a genuine material property in tension while structural (inertia) effects play the major role in compression at high loading rates (up to 1000 s−1). Finally, the model is validated with predicting the experiments of dynamic Brazilian disc test on granite.