锯齿起伏角对断层剪切滑移特性影响研究OA

Investigating the influence of fault geometry on the shear slip and rupture features and exploring the precursor of rockbursts triggered by shear slip along fault planes are of great significance for understanding such disasters in deep underground mining.This work systematically examined the control effect of asperity angles(0°,10°,30°,and 45°)on the slip features of green sandstone specimens with prefabricated faults by performing biaxial shear friction experiments and combined strain and acoustic emission(AE)monitoring.The following experimental results were yielded.The asperity angle dominates the failure mode:low-asperity angle faults(≤10°)primarily undergo'climbing-sliding'failure,inducing localized stress concentration and significant dilatancy effects.Conversely,high-asperity angle faults(≥30°)transition to'gouge-generating rupture',inhibiting tangential displacement and weakening dilatancy.This shift stems from changes in the stress state on the asperity surface(increased normal stress σs,decreased shear stress τs).The strain monitoring results indicate that the asperity angle regulates the accumulation process and spatial distribution of shear strain,with the 30° fault exhibiting the highest accumulated shear strain(6％).The AE monitoring results demonstrate that high-asperity angle faults(45°)release 96.8％of their energy in Stages Ⅱ-Ⅲ,offering shorter early-warning times;the proportion of shear cracks generally grows from 53.5％to 58.1％as the asperity angle rises from 0° to 45°,accompanied by expanding crack ranges.The research findings provide an experimental basis for critical early-warning of fault-slip rock bursts in deep underground mining.