1. Ph.D. Student, Geotechnic and Transportation Dept., Faculty of Civil Engineering, Univ. Teknologi Malaysia (UTM), 81310 Skudai, Johor, Malaysia.
2. Associate Professor, Geotechnic and Transportation Dept. and Fellow, Center of Tropical Geoengineering (Geotropik), Faculty of Civil Engineering, Univ. Teknologi Malaysia (UTM), 81310 Skudai, Johor, Malaysia.
3. Associate Professor, Civil Engineering Dept., Southern Illinois Univ., Edwardsville, IL 62026-1800.
4. Postdoctoral Research Associate, Dept. of Civil and Environmental Engineering, Mississippi State Univ., Mississippi State, MS 39762 (corresponding author).
5. Senior Lecturer, Geotechnic and Transportation Dept., Faculty of Civil Engineering, Univ. Teknologi Malaysia (UTM), 81310 Skudai, Johor, Malaysia.