1. Dept. of Civil and Environmental Engineering, Colorado School of Mines, Golden, CO; Priority Research Centre for Geotechnical Science and Engineering, Univ. of Newcastle, Callaghan, NSW, Australia.
2. Priority Research Centre for Geotechnical Science and Engineering, Univ. of Newcastle, Callaghan, NSW, Australia.
3. Dept. of Engineering Mathematics, Dalhousie Univ., Halifax, NS, Canada.