Experimental behaviour of a compacted silt used in a flood defence embankment in Indonesia

A flood embankment in East Java, Indonesia with a recurrent history of geotechnical failure is the focus of this research. The site was visited in May 2006 and this paper describes the study site and presents the relevant in-situ data. Laboratory characterisation of the sampled material was carried out and presented herein are the soil properties, particle size distribution curve and x-ray diffraction results. Soil water retention curves were determined through the use of three different methods: filter paper, tensiometer and pressure plate allowing a comparison of these methods. Four series of oedometer tests were carried out under: (i) dry-of-optimum, (ii) wet-of-optimum, (iii) prepared wet and then dried and (iv) close to optimum initial conditions. Where collapse was observed, the collapse potential for the specimen was evaluated and severity of collapse determined. These preliminary results show the importance of good compaction control at the site and help to explain some failures observed at the site.