Frictional Characteristics of Granite Fault under Imposed Dynamic Normal Disturbance Loads

Abstract Fault activation induced by dynamic normal disturbance loads resulting from activities such as blasting, excavation, and earthquakes has the potential to trigger significant geological disasters, such as rock bursts, posing a threat to the stability and safety of rock engineering projects. In this study, we report on laboratory experiments to investigate the response of simulated faults. These experiments involved the use of bare granite surfaces to mimic fault behavior, while considering various initial stress ratios and applied normal disturbance loads. The application of normal disturbance loads led to the generation of consistent oscillations in shear stress, apparent friction coefficient, normal displacement, and shear displacement for both inactive and active faults. The experimental results suggest that the activation of faults can indeed be induced by applied normal disturbance loads, and larger initial stress ratios and disturbance loads tend to promote the activation of these simulated faults. Furthermore, we explored the effects of initial normal stress, initial shear stress, disturbance amplitude, and disturbance frequency on the primary quantified parameters associated with the simulated fault. Additionally, we conducted a preliminary discussion on the slip mechanisms of the simulated fault under dynamic normal disturbance loading and its potential engineering implications.