June 22 - 25, 2025
Delta Hotel and Conference Centre
Ottawa, Ontario, Canada
Biography
Delwyn G. Fredlund has spent over 40 years conducting research into the behavior of unsaturated and expansive soils. Most of his career was spent at the University of Saskatchewan, Saskatoon, where he organized the Unsaturated Soils Group for research into all aspects of unsaturated soils behavior. Presently Del heads the Golder Unsaturated Soils Group linking the worldwide offices of Golder Associates. His research studies have involved all areas of unsaturated soil behavior; ranging from the flow of water and air through unsaturated soils to the shear strength and volume change of unsaturated soils.
Del Fredlund obtained his B.Sc. degree from the University of Saskatchewan, Saskatoon in 1962. He went to work for the Division of Building Research of the National Research Council in Saskatoon, Sask. He then went on to obtain his M.Sc. degree in 1964 from the University of Alberta, Edmonton.
In 1966 Del Fredlund accepted a position in the Department of Civil Engineering at the University of Saskatchewan, Saskatoon, Canada. In 1973 he obtained his Ph.D. after returning to the University of Alberta for his studies. During his career he supervised over 75 M.Sc. and Ph.D. graduate students. He became the Head of the Department of Civil Engineering at the University of Saskatchewan from 1989 to 1994. He has also been appointed as an Adjunct Professor at a number of national and international universities.
Fredlund’s research studies have focused on unsaturated soil mechanics and the behaviour of unsaturated soils. He is the author, along with Harianto Rahardjo, of the book “Soil Mechanics for Unsaturated Soils”, published in 1993. He is also a co-author of the book, “Unsaturated Soil Mechanics in Engineering Practice”, along withRahardjo and Murray Fredlund, published in 2012, both books by John Wiley & Sons, New York. Dr. Fredlund has published approximately 500 journal and conference research papers and has delivered many keynote lectures at conferences.
Abstract
The boundary between the saturated and unsaturated soil occurs at the top of the capillary zone and corresponds to the air-entry value, aev. The capillary zone may be a few centimeters in thickness for sand but may be meters in thickness for clay soil. One of the primary pieces of information of value to a geotechnical engineer is the aev for the uppermost soil strata. It is difficult to agree upon a single-valued aev because of the hysteretic nature between the drying and wetting modes. The unsaturated soil properties have been shown to be most accurately correlated with the degree of saturation of the soil. Generally, gravimetric water content versus suction is measured and then the degree of saturation is calculated through use of the shrinkage curve, SC. This paper highlights the important role of measuring and/or estimating the shrinkage curve for the quantification of unsaturated soil property functions, USPFs.