Field instrumentation case study at a pilot site in the Changi land reclamation project

Abstract

Since the early 1990's till early 2000s, the Changi East Reclamation Project in the Republic of Singapore involved the filling of approximately 200 million cubic meters of sand for the reclamation of a total land area of about 2500 hectares. The land reclamation works were carried out in 5 phases. The edges of the newly reclaimed land in the project were either retained by vertical retaining structure or coastal shore protection rock bund with suitable slopes and stability berms. Land reclamation was carried out using fill materials derived from dredging granular material from the seabed at the borrow source. Prefabricated vertical drains with surcharge were used extensively in the project to accelerate the consolidation process. In addition, the hydraulically placed sandfill was densified by using various deep compaction methods. Geotechnical instruments were required to monitor the settlement and pore pressure during the consolidation of soft soil. During the implementation of the 5 phases of land reclamation and soil improvement projects, geotechnical instruments of various types were installed. In order to monitor the performance of ground improvement and to validate the efficiency of the prefabricated vertical drain system several geotechnical instruments were installed in a Pilot Test site within one of the phases of work. This paper provides a case study of the performance of a Pilot Test Site carried out in the Changi East Reclamation Project (Phase 1B).