Load stepping schemes for critical state models

This paper investigates the performance of various load-stepping schemes for nite element analysis with critical state soil models. The accuracy of simple incremental schemes is found to be strongly in uenced by the load increment size, the type of ow rule, and the overconsolidation ratio. Similarly, these factors are shown to have a pronounced e ect on the e ciency and stability of some classical iterative schemes. Unless they are performed with small load steps, critical state analyses with xed increment sizes frequently exhibit non-convergent behaviour or lead to inaccurate solutions. The automatic incrementation schemes developed by Abbo and Sloan (International 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 meth- ods for integrating systems of ordinary di erential equations, are shown to be e cient, accurate and robust solution techniques for a wide variety of critical state problem