Strainburst phenomena and numerical simulation of self-initiated brittle rock failure

Abstract

This paper focuses on ‘self-initiated’ strainbursts, and starts by providing an overview of these phenomena and their relevance to mining. This is used to set the framework for the numerical simulations presented in the second part of the paper. The numerical simulations examine and address challenges in modelling strainbursts related to the inherent difficulties in dynamic failure simulation. Existing methods either simulate dynamic failure under static or pseudo-static conditions while adopting some threshold factor (normally in terms of stress, strain, or energy) as an indicator of rockburst potential, or incorporate an assumed dynamic disturbance to cause rockburst damage. A distinct-element bonded block method is presented to simulate strainbursts. Instead of triggering failure by an assumed dynamic disturbance, the adopted method simulates the generation of a seismic event by self-initiated rock mass fracturing. This simulation of a self-initiated strainburst is interpreted using patterns of cracking, displacement and strain fields, ground velocities, and calculated kinetic and dissipated slip energies. The mechanisms of self-initiated strainbursting are successfully captured by the distinct-element bonded block method.