Engineering grad student perfecting model for destructive 'expansive soils'
By Trevor Pritchard
Admittedly, you probably won't be seeing them featured in a Hollywood summer blockbuster anytime soon. But expansive soils - which Civil and Geological Engineering PhD student Hung Q. Vu terms the "hidden disaster" - are, in terms of sheer financial expense, just as destructive as many other ecological calamities.
"In the U.S.," says Hung, "the costs associated with damage [resulting from expansive soils] to all types of structures is greater than the combined damage from national disasters such as floods, earthquakes, hurricanes and tornadoes." According to current financial reports, expansive soils cause a staggering $7 billion worth of damage to structures in the U.S. Expansive soils also represent "the most costly hazard to buildings built on shallow foundations in Canada," requiring millions of dollars to be spent yearly on repairs to roadways, airport runways, irrigation canals, and underground infrastructure.
Expansive soils are characterized by the presence of the mineral montmorillonite, Hung explains. When soils containing montmorillonite undergo a change in pore-water pressure, they tend to swell, creating physical stress upon any structures built in the immediate vicinity. Changes in the pore-water pressure, according to Hung, can be caused by a number of different factors including climate variation, the removal of vegetation from a specific area, even the excessive watering of one's lawn.
Although expansive soils can be found throughout Saskatchewan, they are particularly concentrated in the Regina region, where soils containing montmorillonite were formed by the evaporation of post-glacial lakes more than 10,000 years ago. These soils also manifest themselves throughout Alberta and Manitoba, says Hung.
Hung's PhD project involves the creation of a reliable model which would be able to accurately predict the amount of heave caused by expansive soils in two or three dimensions. Prior models have been unable to account precisely for the complexities of predicting soil expansion in more than one dimension, requiring engineers to base their estimates of heave on assumptions and extrapolations taken from previous data. Hung hopes his model will eliminate much of the guesswork.
"The more difficult the problem is, the more excited you get when the problem is solved," enthuses Hung. "The work I have done is far from complete. There are a lot of issues we still have to solve."
Overcoming challenging obstacles, however, has been a matter of course for Hung throughout his life. Born in Hai Duong, Vietnam in 1967, Hung's childhood years were spent growing up amidst the horrors and atrocities of the Vietnam War.
"I appreciate life much more now. We were very close to death over there - we saw the bombs going over our heads. People here have many opportunities to advance, to explore, to improve our knowledge. We didn't have the chance before [in Vietnam]."
Hung left Vietnam for the former Czechoslovakia in 1985, achieving his Engineering degree in geodesy and cartography from the Slovak Technical University in Bratislava. In 1990 he returned to Vietnam to study at the National University of Civil Engineering in Hanoi, where he met his current supervisor, Prof. Delwyn Fredlund. Stating that Fredlund treated him "like a member of his family," Hung agreed to travel with him to Saskatoon to pursue his graduate work, and has had no regrets about making that decision.
"Professor Fredlund has proven to be an excellent supervisor and a great mentor to me. I feel that I have been fortunate to have had the opportunity to work under his guidance for both my M.Sc. and PhD programs."
A true polyglot, Hung speaks fluent English, Vietnamese, and Slovak and is competent in French and Russian. Although he has recently accepted a permanent position with the Department of Civil and Geological Engineering as a research engineer, he still has hopes of one day returning to Vietnam with his wife and their two children.
"I would want to go back to Vietnam and teach in University, but I'd like to [first] get experience working in industry."
For Fredlund, it was obvious from the start that Hung had the capabilities to prosper at the University of Saskatchewan.
"Hung Vu was my chauffeur as well as a geotechnical engineer during my first visit to Vietnam," recalls Fredlund. "The traffic is extremely congested in Hanoi, and I figured that anyone who could manoeuvre his vehicle through that traffic could also do well in a graduate program in geotechnical engineering. And he has truly proven himself to be a competent and capable student."