2.7.1 Introduction to Unsaturated Soils
Historians and librarians have the job of classifying what the rest of us do for a living and when we did it. Art historians write texts defining when famous artists were working in their pink period, their blue period or their charcoal period. Relative to my career, they will probably classify it by the five-year structural period, the 20-year saturated clay period, the 20-year unsaturated sand period, and the 20-year teaching/mentoring period. I started as a structural engineer and went into geotechnical engineering in Ohio where we had saturated clays. I moved to New Mexico and had to learn unsaturated soil mechanics in silty sandy soils. During most of this time, I taught classes in mechanics, structural engineering and geotechnical engineering to students and practicing engineers. Currently I have transitioned into the last 20-year period of mentoring practicing engineers and geotechnical faculty. But no matter what the classification categories are called, I have always thought that I was solving problems and having fun!
When I was an undergraduate engineering student in the 1960s I never heard of unsaturated soil mechanics (to the best of my recollection). When I was a graduate student I heard about capillarity and strength of unsaturated soils due to suction (like a ball of moist sand on the beach), but we didn't do anything with this information in design classes. During the first 20 years of my professional ...