On the use of drucker-prager failure criteria for earth pressure problems

Abstract Numerical methods are of considerable help in obtaining a better understanding of the behaviour of geomaterials and have become a standard tool for analysing complex problems in geotechnical engineering. Highly sophisticated constituttive models have been developed and are employed in the scientific world. However, practical engineers very often prefer relatively simple elastic-perfectly plastic material models. In this paper the response of frequently used failure criteria, namely different forms of the Drucker-Prager criterion, are investigated by solving a simple earth pressure problem. The study reveals that all Drucker- Prager models represent a poor approximation of the Mohr-Coulomb failure surface and may lead to higher computing costs. This fact is well acknowledged by the scientific community but is nevertheless often ignored in practice. The results presented here strongly suggest that for earth pressure problems a proper Mohr-Coulomb failure surface should be used when the application of more refined models is not possible or justified.