描述岩石结构面形貌特征的一个重要作用就是为了能更好地理解结构面的剪切行为。首先，从结构面剪切具有方向性的特点出发，抓住在剪切方向上对剪切行为起关键作用的结构面形貌特征，提出描述结构面形貌特征的参数抗剪系数SC。该参数描述了在剪切方向上二维形貌的起伏特征、起伏的统计分布特征以及高度特征，并且还可以表征结构面形貌的方向性。同时，在对10条节理粗糙度系数JRC标准曲线的数字化基础上，建立了抗剪系数SC与JRC值之间的拟合关系。基于三维白光扫描技术得到的自然岩石结构面的点云数据，进一步将抗剪系数SC进行了三维化扩展，使其能够较好地描述结构面的三维形貌特征。最后，以某自然岩石结构面为算例，用三维抗剪系数SC3D度量其沿不同分析方向上的形貌特征，结果表明，抗剪系数能很好地表征结构面形貌特征的各向异性。

Description of rock morphology is of great significance to better understand the shear behavior of the discontinuities. Firstly, from the shear directional characteristics of the discontinuities, a new index SC (shear coefficient) describing discontinuities morphology is proposed based on some pivotal role on shear behavior of its morphology in the shear direction. The index describes undulation characteristics, statistical distribution of undulation and height characteristics of two-dimensional discontinuities morphology in the shear direction, and can also characterize directionality of the morphology. Moreover, the relationship between SC and JRC (joint roughness coefficient) is established based on 10 digitized JRC standard curves. Then, with the help of point cloud data of rock discontinuities obtained by three-dimensional (3D) white scanner, the shear coefficient SC is extended to 3D to better characterize 3D morphology characteristics of discontinuities. Finally, the three-dimensional shear coefficient (SC3D) is used to quantify morphology of natural rock discontinuities in different directions. It is shown that SC can well represent anisotropic morphology characteristics of discontinuities.