NUMERICAL STUDY OF CRITICAL-BEHAVIOR OF DEFORMATION AND PERMEABILITY OF FRACTURED ROCK MASSES

The connectivity of fractures in rock masses is determined using a num erical simulation method. There is a continuous fracture cluster throu ghout a fractured rock mass if fracture density (d) is at or above a t hreshold fracture density d(c), Fractal dimension (D-f) is used to des cribe the connectivity and compactness of the largest fracture cluster s. D-f increases with increasing fracture density. Percolation theory is used to determine the universal law, D-f = A(f)(d-d(c))(f), which d escribes the critical behaviour of connectivity of fractures in rock m asses. The results from numerical modeling show that the deformability of fractured rock masses increases greatly with increasing fracture d ensity (i.e., fractal dimension), and the critical behaviour of deform ability can be described by B-s = A(d-d(f))(s). Also, the overall perm eability of a fractured rock mass occurs at or above a critical fractu re density (d(c)) and increases with increasing fracture density. The critical behaviour of permeability can be described by q = A(p)(d-d(c) )(p). The critical behaviour of connectivity and permeability of natur ally fractured rock masses is examined using the universal forms. (C) 1998 Elsevier Science Ltd. All rights reserved.