Shear mechanical properties and frictional sliding responses of rough joint surfaces under dynamic normal displacement conditions

A comprehensive understanding of the dynamic frictional characteristics in rock joints under high normal load and strong confinement is essential for ensuring the safety of deep engineering construction and mitigating geological disasters.This study conducted shear experiments on rough rock joints under displacement-controlled dynamic normal loads,investigating the shear behaviors of joints across varying initial normal loads,normal loading frequencies,and normal loading amplitudes.Experimental results showed that the peak/valley shear force values increased with initial normal loads and normal loading frequencies but showed an initial increase followed by a decrease with normal loading amplitudes.Dynamic normal loading can either increase or decrease shear strength,while this study demonstrates that higher frequencies lead to enhanced friction.Increased initial normal loading and normal loading frequency result in a gradual decrease in joint roughness coefficient(JRC)values of joint surfaces after shearing.Positive correlations existed between frictional energy dissipation and peak shear forces,while post-shear joint surface roughness exhibited a negative correlation with peak shear forces through linear regression analysis.This study contributes to a better understanding of the sliding responses and shear mechanical characteristics of rock joints under dynamic disturbances.

断层对工作面开采影响数值模拟研究

为了安全高效地采出煤炭资源,采用FLAC^(3D)数值模拟手段,研究了采动条件对断层的影响,分析了工作面采动断层活化特征进行,然后建立数值模型,对断层尖灭部位两盘沿垂直断面和断层面的位移动态变化规律进行了研究。研究得出:在垂直断面层面上,随着工作面的推进,断层两盘垂直断层并没有发生明显的位移;在断层面上,断层两盘沿断层面发生了一定程度的滑动,最大位移达3 m。