Unified modeling of the monotonic and cyclic behaviors of sand and clay

In this study, we aim to investigate a unified modeling method for the monotonic and cyclic behaviors of sand and clay. A simple double-yield-surface model, with plastic hardening modulus and dilatancy relation being dependent on density state unlike in existing approaches, is developed by considering the location of the critical state line. The model is used to simulate the drained and undrained tests of various sands and clays under monotonic and cyclic loadings. Prediction results are compared with experimental results, which show that the proposed approach is capable of modeling the monotonic and cyclic behaviors of sand and clay.