Chen and Tonon (2011) showed that groundwater inflows in rock tunnels typically concentrate in narrow zones where conducting fractures cluster together. A geostatistical methodology was proposed to simulate clustered fractures. In this paper, the resulting discrete fracture network is generated and simplified. An existing analytical-numerical method (Long et al., 1985) for steady fluid flow in three-dimensional, random networks of fractures is improved and used to simulate groundwater flow and predict groundwater inflow into tunnels. Several synthetic tunnel cases and an actual case history at the South Cobb Tunnel Project (GA) are used to validate the flow analysis. It is found that flow concentration can be reproduced by using the proposed technique in the simulated discrete fracture network.
