Load stepping schemes for critical state models

This paper investigates the performance of various load-stepping schemes fo r finite element analysis with critical state soil models. The accuracy of simple incremental schemes is found to be strongly influenced by the load i ncrement size, the type of flow rule, and the overconsolidation ratio. Simi larly, these factors are shown to have a pronounced effect on the efficienc y and stability of some classical iterative schemes. Unless they are perfor med with small load steps, critical state analyses with fixed increment siz es frequently exhibit non-convergent behaviour or lead to inaccurate soluti ons. The automatic incrementation schemes developed by Abbe and Sloan (Inte rnational Journal for Numerical Methods in Engineering 1996; 39: 1737-1759; Proceedings of 5th International Conference, Owen DRJ, Onate E, Hinton E. International Center for Numerical Methods in Engineering, Barcelona, 1997; 1:325-333), which are based on standard methods for integrating systems of ordinary differential equations, are shown to be efficient, accurate and r obust solution techniques for a wide variety of critical state problems. Co pyright (C) 2001 John Wiley & Sons, Ltd.