Engineers Australia

Prediction of collapse potential for silty glacial sand

A. T. M. Z. Rabbi, M. M. Rahman and D. A. Cameron


This paper examines the wetting induced collapse behaviour of three different silty glacial sands from South Australia. Single-oedometer collapse testing was applied to determine the wetting induced collapse settlement. For each soil, three different initial dry unit weights (one close to the field dry unit weight) were used to investigate the effect of dry density ratio. For each dry unit weight, specimens were inundated at varying pressure to investigate the effect of wetting pressure. Dry density ratio, percent of clay fraction, wetting pressure and the initial degree of saturation were found to be the key factors controlling the collapse behaviour of soil. A new empirical equation was proposed to predict the collapse potential of soil depending on the aforementioned factors. The empirical equation gave good predictions for the South Australian silty sand. Verification of the proposed equation was performed using existing data from the literature. The proposed equation gave much better estimates than that obtained from existing prediction equations.