1. Geotechnical Engineer, T. Y. Lin International Pte. Ltd., Singapore 159471; formerly, Research Student, School of Civil and Environmental Engineering, Nanyang Technological Univ., Nanyang Ave., Block N1, No. 1a-29, Singapore, 639798 (corresponding author). E-mail: xubo@pmail.ntu.edu.sg
2. Associate Professor, School of Civil and Environmental Engineering, Nanyang Technological Univ., Singapore 639798. E-mail: bklow@alum.mit.edu