EFFECT OF FRACTURE GEOMETRY AND DOMAIN SIZE ON CONNECTED FLOW BEHAVIORS OF 2-D DISCRETE FRACTURE NETWORK SYSTEM

This study provides a conceptual insight to the relation between the fracture geometry parameters and the behaviors of connected fluid flow through fracture network. Extensive numerical experiments have been carried out to investigate effect of fracture geometry and domain size on hydraulic characteristics of fractured rock masses based on connected pipe flow in DFN(discrete fracture network) systems. Using two fracture sets, a total of 72 two-dimensional fracture configurations were generated with different combinations of fracture size distribution and deterministic fracture density. The directional block conductivity including the theoretical block conductivity, principal conductivity tensor and average block conductivity for each generated fracture network system were calculated using the two-dimensional equivalent pipe network method. There exist significant effect of orientation, density and size of fractures as well as domain size on block hydraulic behaviors. We have been further verified that it is more difficult to define the REV(representatives elementary volume) for the DFN systems with smaller density, size and intersection angle of two fracture sets.