Axisymmetric Cone Penetration Model for Sands and Clays

A direct axisymmetric cone penetration model is developed for implementation with the MIT-S1 constitutive model. Penetration is simulated with the finite difference program FLAC (Itasca) with an Arbitrary Lagrangian Eulerian algorithm that couples FLAC's large deformation Lagrangian formulation with user-written algorithms for rezoning and Eulerian advection remapping. Eulerian remapping of model properties is performed with a second-order method that follows the Corner Upwind Transport method. Numerical examples are used to illustrate the performance of the remapping and advection algorithms and cone penetration simulations.;Penetration is simulated at a Boston Blue Clay site with the Mohr-Coulomb, modified Cam clay, and MIT-S1 constitutive models, and compared to field measured cone penetration test profiles. Single element simulations with Boston Blue Clay calibrations illustrate that the MIT S1 constitutive model captures the strength anisotropy exhibited by Boston Blue Clay, whereas the Mohr-Coulomb and modified Cam clay models do not. Penetration simulations demonstrate the important aspects of (a) capturing the full penetration loading condition, and (b) soil strength anisotropy on the cone tip resistance, stress fields, and pore pressure fields.;Penetration simulations are part of a framework for mechanistically developing liquefaction triggering correlations. The framework is evaluated with laboratory experiments, geotechnical centrifuge experiments, and penetration simulations for Ottawa F-65 sand. Drained penetration is simulated with three MIT-S1 calibrations for Ottawa sand. The calibrations are primarily distinguished by the position of critical state line; penetration simulations demonstrate the dependency of cone tip resistance values on the position of the critical state line. Recommendations are made for future application of the mechanistic framework to develop liquefaction correlations for poorly characterized or unique soils.