Abstract:

For many engineering rock works, such as rock slopes, foundations of dam, underground excavations; calculating the permeability and evaluating Representative Elementary Volume is very important. The Effective Medium Theory (EMT) ap-proach is an alternative method for network permeability calculation. In this way a fracture network can be replaced by a regular network of conductors that are connect-ed to each other at nodes. Then by evaluation suitable effective conductance, permea-bility is calculated. Using Monte Carlo technique, stochastic DFN models were generated with a large number of realizations with the same fracture density and different aperture patterns when distributed fracture trace lengths are correlated/uncorrelated with fracture aper-ture distributions and directional permeability components are calculated with devel-oped new code and compared with numerical results. The results show that the calculated mean values of permeability and approximated permeability tensor with EMT method is well fitted with the numerical simulation results in all fracture patterns.

INTRODUCTION

Calculating of permeability components is very important for understanding the hy-draulic behavior of fractured rock masses. Permeability of fractured rocks is calculated using different methods such as analytical methods reported in (Snow 1969, Oda 1985) or numerical methods reported in (Long et al 1982, Priest 1993, Min et al 2004, Baghbanan 2008). Compared with analytical methods which are mostly used for sim-ple lattice networks, numerical methods are applied for the extensive condition and more complicated models such as large Discrete Fracture Network (DFN) models. However they need large computing resources and are very time consuming. Using Effective Medium Theory (EMT) for calculation the permeability of a lattice network is also reported in the literature as alternative method for numerical solution (Kirkpat-rick 1973, Bernasconi 1974, Harris 1990, Zimmerman &Bodvarsson 1996, Jankovic 2003, Fedrov et al 2005, Baghbanan & Dayani 2009, Dayani & Baghbanan 2010).

This content is only available via PDF.
You can access this article if you purchase or spend a download.