经历剪切变形历史的岩石节理表面形貌变化

采用巴西劈裂法制成四组不同岩性的人工节理面,利用RYL–600岩石剪切流变仪对节理进行不同垂直压应力下的剪切试验,并运用TALYSURF CLI 2000扫描仪在每次剪切前后对节理面进行扫描,计算多个描述节理面形貌特征的三维参数值,通过三维参数值的变化定量分析节理面细观形貌的变化。研究结果表明:节理面抗剪强度的变化与节理面形貌变化有紧密联系,经历四次剪切作用后,节理面整体高度略微降低,各点间的高差缩小;峰点密度减小,节理面的凹凸程度降低;节理表面形态的各向异性程度降低,节理面整体的倾斜程度降低;对于节理面的同一变化,不同参数反映的角度和变化的幅度都不同,随垂直应力的增加,各次剪切作用后节理面的形貌变化量逐渐减小,形貌趋于平整。

Evolution analysis of surface topography of rock joints under different shear deformation histories

Four diverse characters of artificial rock joints were made by Brazilian tests,shear tests of rock joints under different normal stresses which were conducted with RYL-600 rock shear-rheological instrument.Moreover,the surface of each joint was scanned prior to and after each shear test by the scanner instrument TALYSURF CLI 2000.A series of 3D parameters were obtained,and the meso-level topography evolution of rock joint surfaces are quantitatively analyzed through the value alterations of the 3D parameters.The results indicate that the alteration of shear strength is obviously related with the alteration of joint surface topography.After four shear tests,the whole height of joints decreases slightly,so does the altitude differences of points,the density of peaks,the unevenness of joint surfaces,the anisotropy degree of joint surfaces,and the incline of joint surfaces;with regard to the same alteration of joint,the angle and extent that different parameters reflect are different.The topography evolution of joint surface decreases with the alteration of normal stresses,while the surface topography tends to be steady gradually.