IDENTIFICATION OF GRANULAR SOILS STRENGTH AND STIFFNESS PARAMETERS BY MATCHING FINITE ELEMENT RESULTS TO PMT DATA

Abstract : This paper describes an efficient methodology for the identification of soil parameters using the combination of the finite element method and the in situ pressuremeter test (PMT). The objective of the procedure applied here is to identify the parameters of generalized Prager model associated with the Drucker and Prager failure criterion from a pressuremeter expansion curve. The approach consists of minimizing the function representing the difference between the experimental curve and the curve obtained by integrating the model along the loading path in the in situ testing. First, both analytical expressions governing the problem of cavity expansion and those related to the finite element modeling are given in detail. Then, a Fortran computer program called "Press-Sim" along with the solution strategy are described and clearly explained. The influence of some model parameters as well as the probe geometry on the computed pressuremeter curves is examined. The paper finishes by presenting some identification examples drawn from real experimental tests for which the targeted parameters are compared with those of other experimental procedures. Results of comparison show a very good agreement.