中文摘要：

首先，基于节理轮廓线提出一个剪切粗糙度指标（SRI），新指标由3个粗糙度参数构成，描述节理平均起伏度、起伏的方向性、起伏分布特点以及粗糙的分形特性，并建立新指标与JRC之间的拟合关系。其次，基于三角形面积单元离散的三维节理面，将剪切粗糙度指标推广到三维形式，从而使得新指标能够描述节理的三维形貌特征。最后，以张拉型花岗岩节理作为算例，计算结果表明新指标能较好地反映节理的各向异性粗糙特性。新指标物理意义明确，计算方便，能够表征节理的主要粗糙特性，为进一步研究岩石节理的剪切力学特性奠定基础，具有重要的理论意义。

英文摘要：

Firstly, a new roughness index SR/ is proposed based on joint profiles, which consists of three roughness parameters describing average undulation, directivity, distribution and fractal characteristics of joint profile roughness; and the relationship between SR/and JRC（joint roughness coefficient） is also established. Then, SR/is extended to three-dimensional（3D） form based on the triangular element network of joint surface to characterize 3D morphology characteristics of joint. Finally, SR/is used to quantify morphology of tensile granite joint and isotropic morphology characteristics can be represented. The new index has definite physical meaning and can be calculated conveniently. It also can characterize the primary roughness characteristics of rock joint. The new roughness index has set a foundation for further studying the shear mechanical characteristics of rock joint, and it has important theoretical significance for rock mechanics.