3D DEM simulations of CPT in sand

Abstract

The paper contains an overview of the results obtained in a research project exploring the ability of 3D DEM models to reproduce cone penetration in sands. The sand whose behaviour is mimicked by the discrete material is Ticino sand, a well known reference material for cone penetration tests. A large series of numerical experiments in a cylindrical virtual calibration chambers was performed in materials of medium and high density. Point resistance is shown to fit well with results from previous physical tests when the various scaling factors affecting the problem are taken into account. The effect of different boundary conditions on the test results is illustrated. The appearance of friction fatigue in the shaft resistance is also revealed by the analysis of the numerical results. The micromechanics of cone penetration is also illustrated, showing that a stationary condition is clearly attained for point/soil contacts and how particle flow is affected by boundary conditions. From the results presented it can be inferred that 3D DEM simulations offer a feasible alternative to extend and/or partially substitute the more expensive physical calibration tests in the development of CPT based correlations, as well as powerful capabilities to explore the micromechanics of the problem.