Identifying parameters controlling soil delayed behaviour from laboratory and in situ pressuremeter testing

The aim of this paper is to present a methodology for identifying the soil parameters controlling the delayed behaviour from laboratory and i. n si. tu pressurerneter tests by using, an elasto-viscoplastic inodel (EVP-MCC) based on Perzyna's overstress theory and on the elasto-plastic Modified Cam Clay model. The influence of both the model parameters and the soil permeability was studied under the loading condition of pressuremeter tests by coupling the proposed model equations with Biot's consolidation theory. On the basis of the parametric study, a methodology for identifying model parameters and soil permeability by inverse analysis from three levels of constant strain rate pressuremeter tests was then proposed and applied oil tests performed oil natural Saint-Herblain clay. The methodology was validated by comparing the optimized values of soil parameters and the values of the same parameters obtained from laboratory test results, and also by using the identified parameters to simulate other tests oil the same samples. The analysis of the drainage condition and file strain rate effect during a pressuremeter test demonstrated the coupled influence of consolidation and viscous effects oil the test results. The numerical results also showed that the inverse analysis procedure could successfully determine (lie parameters controlling the time-dependent soil behaviour. Copyright (c) 2008 John Wiley & Sons, Ltd.