Affiliation: | 1. Northwestern University, Evanston, IL 60208, U.S.A. Graduate Research Assistant.;2. Northwestern University, Evanston, IL 60208, U.S.A.;3. Laboratoire 3S, UJF, INPG, CNRS, Grenoble, France;4. Institute of Geotechnical and Tunnel Engineering, University of Innsbruck, Techniker Str. 13, A-6020, Innsbruck, Austria |