渗流侵蚀作用对岩石裂隙剪切特性的影响试验

Experiments of seepage erosion influence on shear characteristics of rock fracture

为研究岩体裂隙受渗流侵蚀作用后剪切特性的变化及其演变机理,对新鲜的和经120 h渗透侵蚀作用的两组不同试件进行对比剪切试验,分析了剪切试验曲线、峰值抗剪强度、残余抗剪强度以及初始剪切刚度的变化。试验结果表明:与新鲜粗糙裂隙相比,经过渗流侵蚀作用后的粗糙裂隙剪切应力-剪切位移曲线及法向位移-剪切位移曲线无太大变化,但剪缩位移减小,剪胀位移增大;渗流侵蚀作用后粗糙裂隙表面粗糙程度增大,峰值抗剪强度平均增大8.83%,残余抗剪强度无较大变化,使得残余抗剪强度与峰值抗剪强度之比有所下降;渗流侵蚀作用后粗糙裂隙初始剪切刚度平均增大10.84%。

In order to investigate the variation of shear characteristics of rock fractures after seepage erosion and its evolution mechanism,shear tests were conducted on two groups of specimens in different states.One group was fresh and the other was after a 120 h seepage-erosion experiment.The variations of shear test curve,peak shear strength,residual shear strength and initial shear stiffness were analyzed.The results show that the shear stress-strain curves and normal displacement-shear displacement curves of rough fractures after seepage erosion change little compared with the fresh rough fractures,but the shear contraction displacement decreases and the shear dilation displacement increases.The seepage erosion increases the surface roughness of the fracture,leading to an average increase of the peak shear strength by 8.83%,but with no significant change in the residual shear strength,indicating a declined ratio of residual strength to peak strength.The initial shear stiffness increases by 10.84%on average after seepage erosion.