Prediction of Primary and Secondary Consolidation of a soft soil in the Sydney Basin

This paper presents an approach to predicting the short and long-term consolidation behaviour of a soft alluvial soil in the Sydney Basin. Laboratory testing data, Cone Penetration Testing logs and borehole information were used to characterise the subsoil profile and gain an appreciation of the subsurface variability across the site. S ettlement plate, extensometer and piezometer data assisted the tracking of consolidation of the subsurface layers during the application of preload. An assessment of predictive modelling techniques was undertaken and a method developed by Handy adopted to assist in the estimation of time to completion of primary consolidation. This curve-fitting approach to actual data allows the calculation of the practical completion of primary settlement and assists in the prediction of secondary settlement over the life of the proposed development.