Uncertainty in Constitutive Models

Soils exhibit complex mechanical behaviors. Myriad phenomenological models have been proposed to describe these behaviors, and these models play an important role in geotechnical engineering. Model parameters obtained from any geotechnical site investigation or stress–strain curves obtained from any experimental test are subject to uncertainties due to the inherent spatial variability of ground, the limitations of the experimental techniques, and the limited number of soil samples used. Therefore, uncertainty should be considered in constitutive modeling and the application of constitutive models in geotechnical engineering. This chapter considers uncertainty in three ways: (1) how to develop correlation or surrogate models for soil properties considering uncertainty as key design and model parameters; (2) how to intelligently identify model parameters considering uncertainty from laboratory or in situ tests; and (3) how to integrate uncertainty into the framework of constitutive modeling.