Groundwater flow in three-dimensional discrete fracture network of rock mass

In this study, a program that analyzes groundwater flow in a three-dimensional discontinuity network was developed on the assumption that the discontinuity characteristics such as density, trace length, orientation and aperture have particular and known distribution functions. This program generates discontinuities in a three-dimensional space and analyzes their connectivity and groundwater flow. Due to the limited capability of a PC in this study, REV was not exactly determined, but it was inferred to be greater than 25x25x25 m(3). By calculating the scale of aperture that influences on the groundwater flow, it was found that the discontinuities with the aperture smaller than 30% of the mean aperture had little influence on the groundwater flow. In addition, there was little difference in the equivalent hydraulic conductivity for the two cases with considering and without considering the boundary effect. It was because the groundwater flow was mostly influenced by the discontinuities with large aperture.