1. Institute of Geotechnical Engineering, College of Civil Engineering, Fuzhou University, Fuzhou, P. R. China
2. Institute of Geotechnical Engineering, School of Transportation, Southeast University, Nanjing, P. R. China
3. ENPC, Navier Laboratory/CERMES, Paris, France
4. Faculty of Engineering, The University of Wollongong, Wollongong, NSW, Australia