1. Senior Lecturer, Faculty of Civil Engineering, Univ. Teknologi Malaysia, 81310-UTM Skudai, Johor, Malaysia (corresponding author).
2. Professor of Civil Engineering, Dept. of Engineering, Univ. of Cambridge, Trumpington St., Cambridge CB2 1PZ, U.K.
3. Formerly, Senior Research Associate, Univ. of Cambridge, Trumpington St., Cambridge CB2 1PZ, U.K.
4. Sir Kirby Laing Professor of Civil Engineering, Dept. of Engineering, Univ. of Cambridge, Trumpington St., Cambridge CB2 1PZ, U.K.
5. Geotechnical Engineer, AECOM, 999/9 The Offices at Central World 19th Fl., Rama 1 Rd., Patumwan, Bangkok 10330, Thailand; formerly, Engineer, Land Transport Authority, 219428 Singapore.