Evaluation of Stress-Dependent Methods for the Punch-Through Capacity of Foundations in Clay with Sand

This paper compiled 159 centrifuge tests for foundations in clay with interbedded sand where punch-through failure was observed. The accuracy of initial- and failure-stress-dependent methods was quantified by the mean and coefficient of variation (COV) of a model factor defined as the ratio between the measured and calculated punch-through capacity. When the friction angle is reduced with consideration of the effect of sand dilation, both the initial- and failure-stress-dependent methods can accurately estimate the punch-through capacity of foundations in clay with sand. Numerical analyses were performed to verify the observation. The mean of the model factor is close to 1, and the COV is smaller than 0.3. For multilayer clays interbedded by carbonate sand, they could significantly overestimate the punch-through capacity. This is because carbonate sand has considerably higher compressibility, which is not incorporated into the initial- and failure-stress-dependent methods.