Stiffness parameters from cone pressuremeter tests at Changi East, Singapore

Abstract

A large-scale land reclamation project was carried out in the eastern part of Singapore involving 2000 hectares of land at a foreshore location from 1991 to 2005. The land was reclaimed, by placing sand hydraulically on the seabed comprising soft marine clay. Prefabricated vertical drains with surcharge preloading and deep compaction techniques, were used to improve the soft marine clay and reclaimed sand fill. Several specialist in situ tests were conducted during the project, such as with the cone penetration test (CPT), cone pressuremeter test (CPMT), dilatometer test and self-boring pressuremeter tests. The CPMT is an in situ testing method used to measure both the soil strength and stiffness parameters. The CPMT combines the advantages of a conventional pressuremeter test and a CPT. The CPT provides a continuous profile of the soil by measuring the stress on the cone tip, the sleeve friction and the pore-water pressure. The CPMT enables the assessment of the soil strength and stiffness at selected depths. CPMT tests were conducted on both the reclaimed sand and underlying soft marine clay layers during the Changi East reclamation project.