Critical State Soil Mechanics: A Pore-Based Perspective

Abstract The characterization and modelling of geomaterials at the microscale have typically been focused on soil particles although voids constitute a significant part of soils and play an important role in soil behaviour. Departing from the recent studies on particle arrangement and discrete element modelling of clays, this lecture highlights how clay behaviour can be effectively described at the microscale in terms of pores, and how this can be linked to the mechanical behaviour observed at the mesoscale. To that purpose, a series of compression and shearing tests was carried out on reconstituted clay, and samples of the tested soil analysed by mercury intrusion porosimetry, gas adsorption and scanning electron microscopy in order the map the micro-porosity with recognised states in the critical state soil mechanics (CSSM) framework. Initial results suggest that it is possible to explain some features of CSSM observed at the mesoscale with mechanisms observed at the microscale.