It is very important to notice clay minerals, for resource development, stability evaluation of underground utilization, and others. However, few quantitative data on the effects of clay-mineral type on the swelling characteristics and permeability of clays and clay minerals have been reported to date. This study was conducted to investigate the effects of clay-mineral type on the swelling characteristics and permeability of compacted clays using one-dimensional swelling-pressure and constant-pressure permeability tests. Comparative tests revealed that the difference of clay-mineral type in the clays influences the swelling-pressure and hydraulic conductivity. The swelling-pressure and hydraulic conductivity were closely associated with the specific surface area of clays. Furthermore, hydraulic conductivity was almost consistent that measured with the Kozeny-Carman equation. This result suggests that hydraulic conductivity can be estimated based on a specific surface area and void ratio of compacted clays.

This Paper was Originally Published in Japanese in J. Soc. Mater. Sci., Japan 70 (2021) 272–278. The caption of Fig. 2, and Figs. 2 and 4 are slightly changed.