Strength properties and mineralogy of Singapore old alluvium

Abstract

Old Alluvium is a type of formation, found in the north, north-eastern and north-western part of Singapore. It covers an area of approximately 7200 hectares or about 15% of Singapore. This soil is of economic importance since extensive developments have been, and are being, carried out in this formation. However, in spite of its importance, reliable engineering data of this soil formation is still limited. This study describes the anisotropy behaviour, remoulding effect, microstructure and mineralogy of Old Alluvium. Laboratory tests such as Triaxial, Scanning Electron Microscope, Energy Dispersive Spectroscopy and X-Ray Diffraction were conducted to understand better the behaviour of the soil. The results showed that even though Old Alluvium is naturally a heterogeneous soil and highly variable, it still has a consistent trend of anisotropy. A study of its microstructure and mineralogy helps to explain the presence of natural cementation and bonding in the strength of Old Alluvium.