1. Professor, Institute of Geotechnical Engineering, Transportation College, Southeast Univ., Nanjing 210096, P. R. China (corresponding author). E-mail: zshong@seu.edu.cn
2. Vice-Principal, Oita Prefectual Hitarinkou High School, 30Fukiage-machi, Hita-shi, Oita 877-8691, Japan. E-mail:htph1382@oita-ed.jp
3. Associate Professor, Dept. of Civil, Environmental, and Architectural Engineering, The Univ. of Kansas, 2150 Learned Hall, 1530 W. 15th St., Lawrence, KS 66045-7609. E-mail: jiehan@ku.edu