Keynote speech: Soil improvement for road construction

Prof. Jian Chu

School of Civil & Environmental Engineering, Nanyang Technological University, Singapore

Abstract: Many roads need to be constructed over soft ground. This is particularly the case in Southeast Asia where soft deposits are prevailing along the coastal regions. Three case histories on the use of three different soil improvement methods for roads are presented in this lecture. The first is vacuum preloading method where the vacuum preloading techniques adopted and methods used for the evaluation of degree of consolidation of soft soil under vacuum load are presented. The second case is explosive replacement method where explosive was used to remove soft soil deposit and replace it using crushed rock for road construction in a maintain valley. The method proposed for design and the construction procedure are described. The third method is the use of large-diameter, cast-in-situ concrete piles for road embankment over soft clay. The design detail for the road embankment and the field monitoring data are elaborated.