Instability behaviour of a granular fill material

Abstract

This thesis presents an experimental study on the instability behaviour of a granular fill material retrieved from a reclamation site in Singapore. The study was carried out by conducting specialized triaxial compression/extension tests on loose to medium dense specimens prepared using either the Moist Tamping (MT) or the Water Sedimentation (WS) method. Previous studies on static liquefaction and pre-failure instability behaviour of clean sand were reviewed. A preliminary study on the static liquefaction and run-away instability behaviour of the granular fill material under drained and undrained conditions was conducted. Based on the test data, the failure line (FL), the critical state line (CSL), and the instability line (IL) were determined. The conditions for the occurrence of run-away instability were established. As run-away instability occurs at a stress state below the failure line, it is a type of pre-failure instability.