The hydraulic properties of rock masses are likely to be highly heterogeneous even within a single lithological unit if the rock is fractured . the main difficulty in modeling fluid flow in fractured rock is to describe this heterogeneity 由于岩体中通常包含有大量的各种尺度的裂隙,因此其力学和水力学性质即使是在单一岩性岩层中也是高度非均质的。