Finite element analysis of pressuremeter tests using critical state soil models

This paper presents the results of a numerical study of self-boring pressuremeter tests in critical state soils using the finite element program SNAG developed at the University of Newcastle, Australia The usual interpretation of pressuremeter tests has assumed that the pressuremeter is infinite in length, so that the interpretation can be based on one-dimensional cylindrical cavity expansion theory. This has lead to pressuremeter test results giving soil strengths often significantly higher than those determined by other tests. Previous studies of the effect of finite pressuremeter length have shown that the assumption of an infinitely long pressuremeter leads to an overestimation of soil strength. However, most existing numerical studies have based on the total stress analysis using perfectly plastic soil models. To investigate the influence of soil models in the assessment of finite pressuremeter length effects, a parametric study has been carried out using an effective stress formulation with a variety of strain-hardening/softening critical state soil models. For comparison, numerical results of a total stress analysis were also presented for the perfectly plastic Tresca soil model.