1. Professor, Dept. of Geotechnical Engineering and Key Laboratory of Geotechnical and Underground Engineering of the Ministry of Education, Tongji Univ., Shanghai 200092, China (corresponding author).
2. Ph.D. Candidate, Dept. of Geotechnical Engineering and Key Laboratory of Geotechnical and Underground Engineering of the Ministry of Education, Tongji Univ., Shanghai 200092, China.
3. Assistant Professor, Dept. of Civil, Structural and Environmental Engineering, Univ. at Buffalo, Buffalo, NY 14260.