Short Course: Application of Unsaturated Soil Mechanics in Geotechnical Engineering
Dr. Gerald A. Miller, PE
Rapp Presidential Professor
University of Oklahoma
School of Civil Engineering and Environmental Science
Wednesday, September 18
8:00 A.M. - 12:00 P.M. (CT)
Innovation Hub, Three Partners Place, University of Oklahoma campus
On September 18, 2024, Dr. Gerald Miller, P.E. delivered a half-day short course on “Application of Unsaturated Soil Mechanics in Geotechnical Engineering” to both live and digital participants. Dr. Miller has been a professor at the University of Oklahoma for 30 years and has been active in the geotechnical engineering community throughout his career. The event sponsored by the Southern Plains Transportation Center was held in the Innovation Hub Classroom at Three Partners Place on the University of Oklahoma campus in Norman, Oklahoma. Sixty-three participants attended, representing private, public, and government institutions.
During the first half of the presentation, Dr. Miller provided an overview of basic unsaturated soil mechanics focusing on such topics as soil suction, the soil water characteristic curve, and stress-state variables for unsaturated soils. In the second half, the application of unsaturated soil mechanics in the analysis of laboratory and in situ tests was discussed. Dr. Miller presented data that showed the impact of seasonally varying moisture contents on the results of lab and field tests. He further stressed the importance of considering moisture conditions at the time of subsurface exploration when interpreting the results for geotechnical analysis. To emphasize his points, Dr. Miller focused on examples from his research and consulting work including data from standard penetration testing, unconfined compression testing, cone penetration testing, and seismic velocity testing in unsaturated soils during “wet” and “dry” weather periods. Through some examples, he offered some simplified approaches for estimating changes in field or lab parameters resulting from changes in soil moisture contents in the active zone of a soil profile.
ABSTRACT
In many places throughout the world, including Oklahoma, soil profiles remain in an unsaturated state during much of the service life of overlying structures such as building foundations and pavements. Additionally, it is common for moisture conditions in unsaturated soil profiles to vary considerably in the active zone due to seasonal weather variations and long-term environmental changes including periods of drought. These moisture variations have a profound influence on the mechanical behavior of the soil due in large part to changes in the matric suction, also known as capillary pressure in the soil. It is important that geotechnical engineers consider how these changes in soil behavior affect: 1) the determination of soil properties during their subsurface investigations and 2) the performance of overlying structures supported on the unsaturated soil. This ½-day short course will provide a short overview of important unsaturated soil mechanics concepts, simple methods for conducting and interpreting laboratory and in-situ tests on unsaturated soils, and application of the results in geotechnical engineering. Particular emphasis will be placed on laboratory and in situ testing methods used in everyday practice such as unconfined compression and triaxial compression testing, direct shear testing, standard penetration testing (SPT), cone penetration testing (CPT), and seismic velocity measurements.
BIO
Dr. Gerald A. Miller, PE is currently a Rapp Presidential Professor in the School of Civil Engineering and Environmental Science (CEES) at the University of Oklahoma (OU). He has been at OU since 1994 and most recently served as Associate Director of his school (2013-2022) and Associate Director of the Southern Plains Transportation Center (SPTC) (2013-2019). He received his B.S. (1987) and M.S. (1989) degrees from Clarkson University in Potsdam, N.Y., and his Ph.D. in 1994 from the University of Massachusetts at Amherst. All of his degrees are in the field of civil engineering with an emphasis on geotechnical engineering. Dr. Miller is a registered professional engineer in Oklahoma and has been active in geotechnical research, teaching, and consulting for nearly 37 years. His primary research areas of interest include chemical stabilization of soils and unsaturated soil mechanics with applications to in situ testing, compacted soil behavior, foundation engineering, and soil-structure interaction.
