1. U.S. Army Cold Regions Research and Engineering Laboratory, Engineer Research and Development Center, 72 Lyme Road, Hanover, New Hampshire 03755-1290, USA
2. U.S. Army Construction Engineering Research Laboratory, Engineer Research and Development Center, 2902 Newmark Drive, Champaign, Illinois 61822, USA
3. U.S. Army Geotechnical and Structures Laboratory, Engineer Research and Development Center, 3909 Halls Ferry Road, Vicksburg, Mississippi 39180-6199, USA