The Microstructure and Water Distribution of Partially Saturated Hard Clay

摘要

This article presents an experimental investigation of the microstructure and water distribution of partially saturated natural hard clay. A series of natural hard clay specimens were desaturated using a controlled-suction technique and then examined using nuclear magnetic resonance relaxometry (NMR) and mercury intrusion porosimetry (MIP). NMR allows one to investigate the microstructure and the water distribution of the material, while MIP can provide information about the free space distribution of the material. The results of NMR are consistent with the MIP measurements and show that the pore size of the hard clay has a similar unimodal distribution. The relaxation time distribution curves are closely related to the water content of the specimens. The dehydration mechanism of the hard clay is revealed by both NMR and MIP: the water progressively evaporates from large pores to small pores. The peak of the T-2 relaxation time distribution decreases with a decrease in water content, and the peak of the free pore size distribution increases during hydration. The results of NMR and MIP are consistent and reveal the same dehydration mechanisms. The limits of NMR and MIP for partially saturated materials will be discussed in this text.