Deep excavations in Singapore marine clay

Abstract

Significant areas of the financial and commercial districts of Singapore have been constructed over deep deposits of near normally consolidated marine clay. Numerous deep excavations have been required for urban development and the supporting infrastructure. The design of these excavations needed to consider basal stability and (for walls taken to hard strata) net active forces below excavation level. A number of innovative solutions to these problems have been applied. Solutions have included the use of underwater excavation, lime piles, deep soil mixing and the formation of buried slabs using jet grouting. Generally, these have been successful. However, there have been a number of major excavation failures over the last 10 years. Examples of successful excavations are contrasted with some of the failures, and the causes discussed. © 2006 Taylor & Francis Group.