Abstract
The original Cam-clay model is the earliest critical state soil model. However, the vertex singularity of this model causes the discontinuity on the yield surface and is viewed as a drawback of the model. In this study, a Backward-Euler stress update algorithm is developed for the original Cam-clay model. A constraint function is defined as a plane passing the vertex and Koiter’s associated flow rule was employed to both yield and constraint functions. This method can conveniently handle the vertex without discretizing the yield surface into a finite number of yield loci. The stress update algorithm was tested with six diversified forms of the yield function to consider the effect of yield function’s form on the performance of the algorithm. Numerical results of the proposed algorithm were illustrated in a single step and varying number of sub-steps. Error-maps were successfully generated to evaluate the performance of the algorithm.