结构面粗糙度系数的三维分形表征

Three-dimensional fractal representation of joint roughness coefficient

结构面粗糙度对结构面的抗剪强度有重要影响,进而影响工程岩体的变形破坏行为。基于高精度三维激光扫描技术,以贵州某水库拱坝基岩结构面为研究对象,现场采取泥质白云岩结构面、白云岩结构面、泥质白云岩与白云岩接触面三类优势结构面并对各岩样结构面表面进行扫描,获取三维形貌数据,建立了数字高程模型。采用MATLAB软件编写立方体覆盖法程序,进而精确求取每个结构面的三维分形维数,同时采用均方根方法估算每个结构面的三维粗糙度系数,然后建立两者之间的关系式。研究结果为将结构面粗糙度系数表征方法从二维拓展到三维提供了一种新思路。

The surface roughness of discontinuity has important influence to discontinuity shear strength, and further affects the deformation and failure behavior of rock mass. Based on high-precision 3D laser scanning technology and taking a arch dam in Guizhou as a research object, three kinds of prominent discontinuities in the foundation rock, the argillaceous dolomite disconti-nuity, dolomite discontinuity, and contact surface between dolomite and argillaceous dolomite, were scanned to obtain three-di-mensional topography data and build the digital elevation model. We write cubic covering method program to calculate the three-dimensional fractal dimension of each discontinuity precisely by Matlab, and estimate the three-dimensional roughness coeffi-cients of each discontinuity by using the RMS method and then establish their relationship. The results provide a new idea to de-velop the characterizing method of joint discontinuity roughness from 2D to three-dimensional space.