Effect of Prior Strain History on the Cyclic Strength and CPT Penetration Resistance of Silica Silt

The effect of prior strain history on cyclic strength and cone penetration test (CPT) tip resistance of non-plastic silica silt is evaluated. A series of undrained cyclic direct simple shear (DSS) tests on slurry deposited specimens are performed to characterize cyclic strength. Cyclic strengths are evaluated for maximum shear strains of 1% and 3% in 15 cycles. Drained CPT tip resistances are estimated from simulated cavity expansion limit pressures. Cylindrical cavity expansion simulations are performed in the finite difference program FLAC using a modified version of the MIT-S1 elasto-plastic constitutive model. The evolution of cyclic strength and simulated CPT tip resistance during a series of cyclic loading and reconsolidation stages is presented. The developed relationships between cyclic strength and CPT tip resistance are shown to track the curvature of corresponding semi-empirical q_c1Ncs-CRR triggering curves. Dependence of the presented relationships on failure criterion (maximum shear strain) is shown to be qualitatively consistent with the literature.