This monograph is an assemblage of selected papers that have been authored or co-authored by D.G. Fredlund. The substance of these papers documents the milestones of both the science of unsaturated soil mechanics and the career of the author during his tenure as a faculty member in the Department of Civil Engineering at the University of Saskatchewan, Saskatoon, Canada. The monograph contains nine parts. Part I provides an appreciation of the author, describes his family background, academic training, engineering experience, university career, and many of the contributions that D.G. Fredlund has made as a researcher, teacher, engineer, mentor, and advocate of unsaturated soil mechanics throughout the world.
Part II contains papers that develop the concept of stress state and stress state variables in the treatment of unsaturated soils. The importance and the role of soil suction are also identified.
Part III is a collection of literature that forms the theoretical foundation of the science of unsaturated soils. The papers focus on appropriate soil mechanics concepts for unsaturated soils and emphasize the transition from the unsaturated to saturated state and vice versa. Several papers introduce and describe the importance of the soil water characteristic curve.
Part IV addresses shear strength, one of the most important geotechnical design characterizations required in understanding the behavior of slopes and embankments. The importance of soil suction, including its sustainment and variation with changing environmental conditions, form a common thread throughout these papers. The relationship between the soil water characteristic curve and the shear strength of an unsaturated soil is contained in this section.
Part V contains papers related to steady state and transient flow through unsaturated soils. While the earlier work provided the framework for some of the important concepts of saturated/unsaturated flow, it was the development of the permeability function and its relationship to the soil water characteristic curve that represented a major breakthrough in the application of these concepts to engineering practice. Part VI deals with the important area of volume change. The concept of swelling pressure and a systematic approach to the calculation of swelling (heave) and shrinkage form the primary part of the information presented. Some case histories are also contained in this section.
Part VII provides the background and treatment of moisture flux boundary conditions at the ground surface. The modelling of net infiltration and actual evapotranspiration and its effect on soil suction and storage are the key elements of these papers. Several important numerical models and their application to engineering practice are referred to in this section.
Part VII contains a complete listing of papers published by D.G. Fredlund over the past 30 years. More than 200 titles appear under the various headings of referred journals, books, chapters in books, conference proceedings, and various reports. The list in itself is an attestment to the contribution the author has made to soil mechanics in general and to unsaturated soil mechanics in particular, as well as to the application of these principles in geotechnical engineering practice.
Finally, the Appendix provides a list of the graduate students that D.G. Fredlund has supervised. These students have come from Brazil, Canada, China, Greece, Hong Kong, India, Iran, Kenya, Malaysia, Pakistan, Singapore, Vietnam, and elsewhere. Such a diverse list of students is surely an attestment to the extent of the outreach D.G. Fredlund has provided to the developed and developing nations in the world in terms of both personal development and the transfer of engineering technology.
