Large diameter plate tests on weathered in-situ chalk

The prediction of the settlements of spread foundations on in-situ chalk is best carried out using empirical methods, based on the simple behavioural model developed by Burland & Lord (1970) using results from plate tests. However, the data available to support this approach remain somewhat limited, stratigraphically, geographically and in terms of size and level of loading. This paper reports the results of nine large (1.8 m) diameter plate tests carried out on three weathered chalks with widely different intact densities and strengths. The results are interpreted in terms of the Burland and Lord model, and despite the differences in the chalks at these sites, are found to be broadly in agreement with the parameters deduced on the basis of the pioneering work carried out at Mundford by Ward et al. (1968). In addition the paper provides some additional data on creep settlements, confirming that the long-term settlements on chalk can be considerably larger than those predicted on the basis of short-term loading tests.