GeoChallenges [electronic resource] : rising to the geotechnical challenges of Colorado : proceedings of the 2012 Biennial Geotechnical Seminar, November 9, 2012, Denver, Colorado / sponsored by the Geo-Institute of the American Society of Civil Engineers, Geo-Institute Chapter of the Colorado Section of the American Society of Civil Engineers, Rocky Mountain Section of the Association of Environmental and Engineering Geologists, Colorado Association of Geotechnical Engineers ; edited by Christoph M. Goss, Ph. D., P.E., Jere Strickland, P.E., Richard L. Wiltshire, P.E.