基于裂隙网络模拟技术的结构面分布分维数计算

STUDY ON FRACTAL DIMENSION OF DISCONTINUITY DISTRIBUTY BASED ON SIMULATION TECHNIQUE OF DISCONTINUITY NETWORK

介绍了分形基本概念及工程岩体分形特性,结合裂隙网络模拟技术,分析了计算结构面分布分维数的方法,并给出了工程应用实例。讨论了计算裂隙分维数有效测度范围问题,对裂隙间距、迹长、交角和岩体RQD等影响因素与分维数的关系进行了初步分析,结果表明:间距对分维数影响最大,迹长和交角则相应次之。岩体裂隙分布分维数较RQD更能全面反映岩体的结构特征,用于对工程岩体进行质量评价是可行的,但对于测度尺寸和分维数与岩体工程性质关系等问题有待深入研究。

The fractal concept and the fractal characteristics of rock masses are discussed in general. The box dimension method is studied based on the technique of network simulation,and a calculation sample of fractal dimension for the engineering rock masses in Three Gorges Reservoir region is given. The problem of proper range of box size is discussed. Various factors,such as fracture space,total length of discontinuities,and inclination between joints,are analyzed. The results show that the space of discontinuities affects fractal dimension markedly. It is certain that the index of fractal dimension is better than the index,RQD,on characterizing jointed rock masses and classifying engineering rock masses. At last,some problems on the range of box size and the relationship between fractal dimension and engineering properties of rock masses are pointed out for further study.