关键词: 摩擦实验, 粘滑, 应力扰动, 应力降, 粘滑间隔

Abstract: We have performed a series of frictional experiments using a servo-controlled biaxial loading machine with three granodiorite block direct shear configuration.In the experiments,a small-amplitude sine wave of displacement is modulated to shear loading to study the effects of shear stress perturbation on stick-slip instability.The main results are as follows.Under constant normal stress and constant loading point velocity in shear direction,the sample shows regular stick-slip behavior.After the displacement perturbation is modulated to shear loading,the correlation between the timing of stick-slip and the perturbation increases as the perturbation amplitude increases.Stress drop and interval time of stick-slip events also tend to be scattered,and the critical amplitude for producing significant impact is around 0.05MPa.The tendency that the stress drop and interval time of stick-slip events are scattered with increasing perturbation amplitude is more obvious at higher normal stress,and the correlation between the timing of stick-slip and the perturbation also increases with increasing normal stress at the same perturbation amplitude.The effect of perturbation period on friction is not evident.The results imply that the change in Coulomb shear stress caused by strong earthquake may obviously change not only the occurrence time of earthquakes but also the earthquake magnitude on nearby faults.

Key words: frictional experiment, stick-slip, stress perturbation, stress drop, interval time of stick-slip events