Geotechnical engineer, CH2M Hill, Portland, Ore.
Professor of civil engineering, Purdue University, West Lafayette, Ind.
Pages: 14 Published: Jan 1981
Measurements and use of pore size distributions to explain the behavior of engineering materials are not new. However, there are few, if any, reports of a simplified methodology and its direct application to engineering predictions. This paper explains how pore size measurements and water permeability were correlated for compacted samples of saturated clayey silt. The results strongly support the hypothesis that a new generation of permeability prediction equations is now possible. In the new equations, the old soil parameters of effective grain size, total porosity (or void ratio), and specific surface are effectively replaced by appropriate parameters of the pore size distribution.
The paper recommends the procedure for compacting, saturating, and permeating fine-grained soil samples. Following the permeability tests, small samples are extracted for constant volume dehydration through a quick freeze-sublimation process. Finally, the mercury intrusion technique is used to quantify the distribution of porosity. Study of the distribution plots, particularly the differential frequency one, is very helpful in (a) qualitatively understanding the experimental results and (b) quantifying the data through statistical correlations. Sample data and plots are introduced to reinforce the principal points of the discussion.
permeability, porosity, pore size distribution, fine-grained soils, compaction, freeze-drying, mercury intrusion, groundwater
Paper ID: STP28321S