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

动态法向位移作用下粗糙节理面剪切力学特性及摩擦滑动响应

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.

为了确保深部工程建设的安全和减轻地质灾害,全面了解在高法向荷载和强约束条件下岩石节理面的动态摩擦特性是至关重要的。本研究对在动态法向荷载作用下的粗糙岩石节理面进行了剪切实验,探究了在不同初始法向荷载、法向荷载加载频率和法向荷载加载幅值下节理面的剪切行为。实验结果表明,峰值/谷值剪切力随初始法向荷载和法向荷载加载频率的增加而增加,但随法向荷载加载幅值的增加先升高后降低。动态法向荷载可以增加或减少剪切强度,本研究中更高的法向荷载加载频率会引起摩擦增强。初始法向荷载和法向荷载加载频率的增加导致剪切后节理面的粗糙度系数(JRC)值减小。通过线性回归分析发现,摩擦能量耗散与峰值剪切力之间存在正相关,而剪切后节理面表面粗糙度与峰值剪切力之间呈现负相关。本研究有助于更好地理解岩石节理在动态干扰下的滑动响应和剪切力学特性。