Representation of Compacted Clay Minifabric Using Random Networks

Abstract

This paper demonstrates the application of two-dimensional random networks to quantitatively represent the minifabric of compacted clays. The structure of compacted clays is idealized using aggregations of spherical clusters that in turn are simulated as circles in a two-dimensional plane. Flow is considered to take place in intercluster pores only, and the random network of pores in the minifabric is constructed using constant-diameter pore segments. The maximum diameter of the clusters is shown to govern the important network parameters, viz. the diameter, length distribution, and areal density of pore segments; and connectivity of the network. It is shown that with small clusters, the permeability is low due to the low transmissivities of individual pore segments, in spite of the well-connected nature of the networks. Conversely, for the same intercluster porosity, the permeability corresponding to large clusters is high in spite of the poorly connected nature of the networks, because of the high transmissivities of the individual pore segments. The network representation is applied to prior investigations where necessary data are available, and good agreement is observed between experimental observations of hydraulic conductivity and predictions made by the random networks.