Abstract

The performance of intermediate soils (e.g. silty sands) during dynamic earthquake loading is a primary source of uncertainty in the design of geotechnical systems. The characterization of intermediate soils is challenging due to complications with obtaining high quality samples for laboratory testing and in interpreting soil properties from in situ penetrometer measurements obtained when partial drainage conditions exist. The penetration of the cone at different penetration rates enables control of drainage conditions, and therefore has the potential to improve estimation of drained and undrained soil properties. Cone penetration testing in sands with fines contents up to 35% is explored through drained and undrained cylindrical cavity expansion simulations with a modified MIT -S1 constitutive model. Stress-normalizations of drained and undrained cone tip resistance are explored in terms of the state parameter. Partial drainage effects on the state-normalized cone tip resistance – cyclic resistance ratios used in liquefaction triggering curves are evaluated. The ratio of drained to undrained penetration resistance is then explored to evaluate how the ratio changes with stress level and state. The results indicate that soil stiffness, stress-dilatancy, and limiting compression behaviors are found to be the primary factors that affect the ratio of drained to undrained penetration resistance.