The use of mercury intrusion porosimetry for the analysis of soft clay microstructure

Mercury intrusion porosimetry is used to study the microstructure of a sensitive Champlain clay from Eastern Canada· The clay structure is observed firstly on intact, remolded and oven-dried soils and secondly on soils consolidated at various levels in one-dimensional compression. The investigation confirms for the intact soil the existence of an aggregated structure characterized by an inter-aggregate and an intra-aggregate porosity. Remolding affects inter-aggregate links but does not destroy aggregates. The observation of clay structure at various levels of one-dimensional compression shows that the collapse of the structure is progressive, the largest inter-aggregate pores being the first affected. For a given pressure increment, only the largest existing pores are affected.