1. Geotechnical Research Institute, Hohai University, 1 Xikang Road, Nanjing, Jiangsu 210098, China.
2. School of Civil and Environmental Engineering, Nanyang Technological University, Block N1, 50 Nanyang Avenue, 63798 Singapore.
3. College of Civil Engineering, Hohai University, 1 Xikang Road, Nanjing, Jiangsu 210098, China.