为进一步提高结构面粗糙特征描述的精确性和可靠性，更全面地体现出细微形貌的影响，将轮廓线凹凸起伏分解为幅值、倾角和曲率3个特征，分别代表轮廓线的高度变化、角度变化和弯曲程度变化。以Barton建议的10条标准轮廓线为例，计算其幅度、角度和弯曲度的特征曲线，获得了三者的分布规律。利用可表征微细观形貌的功率谱密度函数研究了3种特征曲线的频谱特征，然后从功率谱密度对数曲线中提取了可以描述形貌特征的分形参数Dj（斜率相关）和粗糙度参数Aj（截距相关），在此基础上研究了Dj 和Aj 与节理粗糙度系数（jointroughness coefficient，简称JRC）的关系。同时，将该指标推广到了三维形貌的表征形式，并计算了大理岩剪切面的三维粗糙度。结果表明：新指标评估精确度高，可反映结构面各向异性特征，能有效表征结构面粗糙特征，对研究结构面剪切力学性质有重要意义。To further improveaccuracy and reliability of describing the roughness feature of the structuralplane

and more comprehensively reflect influences of the morphologicaldifferences

the fluctuation of the profile was decomposed into threeprincipal characteristics: amplitude

inclination

and curvature

which represent the change characteristics of height

angle

and bending of the profile. The data of the three characteristics were obtained by10 standard profiles established by Barton. And the distribution curves of thethree characteristics were analyzed. Then

the power spectral density (PSD)

which can well describe the microscopic morphology

was used to analyze thespectral characteristics of amplitude

inclinationand curvature. The fractalparameters Dj (correspondingto the slope of the PSD curve) and roughness parameters Aj (correspondingto the intercept of the PSD curve) were got from the logarithmic PSD curves.The relationship among Dj

Aj and the joint roughness coefficient (JRC) wasstudied

and the expressive forms of JRC with the new index were established. Meanwhile

the newindex was extended to reveal the characterization of three-dimensionalmorphology

which was also used to calculate surface roughness of a marblesurface obtained by the shear test. The results show that the new index has anextremely slight evaluation error

and canreflect the anisotropic property and effectively character morphology featuresof the structural plane

which provides a reference for characterizing theroughness of the structural plane and it is of great significance to studyshear mechanical properties of the structural plane.