NUMERICAL-SIMULATION OF CUMULATIVE DAMAGE AND SEISMIC ENERGY-RELEASE DURING BRITTLE ROCK FAILURE - PART I - FUNDAMENTALS

This paper presents a numerical approach for the simulation of damage initiation and propagation causing seismic energy release during unsta ble failure of brittle rock. With a newly developed numerical code, RF PA(2D) (Rock Failure Process Analysis), the progressive failure proces s leading to the development of a shear or fault zone, and the eventua l collapse of a heterogeneous rock sample is modeled. Since the consti tutive law for each element in the model is elastic-brittle, seismic-b rittle, seismic energy is radiated whenever an element fails. It is as sumed that the radiated energy is equal to the energy stored in the el ement before failure is triggered. Due to the heterogeneity of rock pr operties, seismic quiescence may occasionally occur within the nucleat ion zone. The cumulative seismic damage calculated based on the seismi c event rate from the simulation can be used as a damage parameter to describe the damage evolution. It was found that significant decreases followed by sudden increases in radiated seismic energy may be an ind icator of potentially unstable nucleation. (C) 1998. Published by Else vier Science Ltd.