Effective stress analysis of soil response in a pressuremeter test

A simple rheological model for analyzing pressuremeter test results, which includes pore water pressure measurements, is presented. The soil is assumed to be an elasto-plastic material with a non-associated flow rule. The governing equation of the yield surface and the plastic flow potential are based on parameters which can be obtained from standard tests, such as triaxial compression tests. A parameter is introduced which accounts for the contracting and/or dilating behavior of the soils during expansion. The model is applied to pressuremeter test results obtained in a contracting, lightly overconsolidated clayey silt. The shear modulus, effective strength characteristics, and a parameter characterizing the contracting behavior of the soil are determined. The results of a numerical analysis, incorporating the proposed rheological model, simulating the pressuremeter tests are compared with the field test results.