1. Associate Professor, Dept. of Civil Engineering, Monash Univ., Building 60, Melbourne, Vic. 3800, Australia (corresponding author).
2. Assistant Professor, Ubon Ratchathani Univ., P.O. Box 3, Warin Chamrap, Ubon Ratchathani 34190, Thailand.
3. Professor in Civil Engineering, School of Engineering, Univ. of Surrey, Guildford, Surrey GU2 7XH, U.K.; Director, Environmental Geotechnics Limited, Oxford, U.K.