剪切作用下节理表面形貌变化

 岩石不连续面的粗糙度对节理岩体的剪切力学性质有重要影响。为研究剪切作用下节理表面形貌变化,对5组节理试样进行了2次剪切试验,借助三维非接触式高精度激光形貌仪(Talysurf CLI 2000)对每次剪切前后节理表面进行扫描测试,从微观和宏观方面分析了节理表面形貌在剪切作用下的变化,得出如下结论：(1) 节理峰值抗剪强度与节理表面形貌有较大关系;(2) 经过2次剪切试验,节理表面较高高度范围内峰点数量减少,较低高度范围内峰点数量增加;(3) 经过2次剪切试验,节理表面最大高度降低,凸起体高度普遍下降,中间高度凸起体分布增加;(4) 经过2次剪切试验,节理表面轮廓线的包络线呈下降趋势,平均轮廓线也呈下降趋势,下降高度与法向应力有关。

Topography Evolution of Joint Surface Under Shear Loads

It has been long recognized that the roughness of rock discontinuities could have a significant impact on the shear strength characteristics of discontinuous rock masses. In order to study topography evolution of joint surface after shear tests, five samples were sheared two times and joint surfaces were scanned before and after each shear test with the 3D non-contact high-accuracy laser topography instrument (Talysurf CLI 2000). Topography evolution of joint surface is both macroscopically and microscopically analyzed, and the following conclusions are gotten: (1) the peak shear strength is related to the topography of joint surface; (2) after two shear tests, the number of peaks for the higher height of joint surface decreases, while that for the lower height of joint surface increases; (3) after two shear tests, the maximum height of joint surface decreases, the height of most asperities drops and the number of middle-height asperities rises; (4) after two shear tests, both of the envelope and the mean profile of joint surface tend to go down, and the descending height is related to the normal stress.