Cavity expansion in sands with applications to cone penetrometer tests

Abstract

The deduction of soil properties from cone penetration tests relies largely on the correct interpretation of the test results. In this dissertation the expansion of cylindrical and spherical cavities in sands is studied using a state parameter constitutive model. This model takes into account the dilatant aspect of the shear behaviour, allows shear strength parameters to be dependent on the stress and deformation history, and employs a non-associated plastic flow rule. Large strain effects are included. A similarity solution technique is used to obtain solutions for the expansion of created cavities. This is valid for problems of rate-independent materials with no characteristic length. These solutions can be viewed as the asymptotic solutions to those for the expansion of cavities from finite initial radii. Comparisons are made between the numerical results of this study and those previously obtained using perfectly plastic models. Theoretical predictions of the limit pressure from spherical cavities are applied to analyse the process of the cone penetrometer test. The values of the predicted cone resistance are compared with those measured from large scale calibration chamber tests. Based on the results of the study, a procedure is suggested for the deduction of shear strength parameters from the measured cone resistance for sands.