Unified CPTu-based probabilistic model for assessing probability of liquefaction of sand and clay

In this paper, a mathematically rigorous process is adopted to derive a piezocone penetration test (CPTu)-based model for assessing the probability of liquefaction/cyclic softening. The new probabilistic model is expressed in the form of a mapping function that relates the liquefaction probability mathematically to the factor of safety obtained from a published deterministic CPTu-based model. The new model is novel because it is applicable to both sand and clay, is more direct (in terms of the usage of CPTu data), is more consistent with a mechanics framework, and allows complete liquefaction assessment (at least for initial screening) without recourse to additional sampling and laboratory testing. Possible variation of the model caused by the variability of the adopted database is investigated and reported. Finally, examples are provided to demonstrate how the proposed model is applied in a future event considering both model and parameter uncertainties.