Pore Distribution and Permeability of Silty Clays

This investigation utilizes pore size distribution measurements to examine the relationship between permeability and compactive variables for laboratory compacted clayey silts. Closed-system falling head permeability tests under back pressure were performed on each of the compacted samples. Freeze drying was successfully used to dehydrate specimens prior to pore size measurements. The mercury intrusion technique was used to determine the pore size distribution. The pore size distributions of the soils tested were bimodal with a large pore mode occurring between 10 ? and 1 ? and a small pore mode occurring at 0.1 ?. Varying the compaction variables produced changes in the size and frequency of the large pore mode, but caused no change in the pore size distribution about the small pore mode for a given soil type. Three theoretical permeability models that relate pore size distribution parameters to permeability were generated. These parameters were successfully used to determine empirical permeability prediction equations for the soils tested.