Influence of Particle Properties and Initial Specimen State on One-Dimensional Compression and Hydraulic Conductivity

Abstract

Particle crushing can adversely affect geotechnical system performance; examples include clogging in wells, pile shaft capacity degradation, and postconstruction settlements. The generation of fines results in volumetric compression and a reduction hydraulic conductivity, which is important for geotechnical systems whose performance is directly dependent on pore pressure dissipation, groundwater flow, or hydraulic pumping. Knowledge of hydraulic conductivity change is poorly understood due to limited experimental data, and an ability to predict this change is lacking. The role of single particle properties, initial specimen state conditions, and loading conditions on the evolution of hydraulic conductivity with particle crushing was examined experimentally. Specimen response exhibited an overshoot behavior and the convergence to a unique condition independent of initial relative density, gradation, and particle shape. The hydraulic conductivity decreased by 2–3 times before specimen yield, and by 2–3 orders of magnitude after specimen yield. Empirical correlations were developed to estimate the change in hydraulic conductivity given the initial permeability and select crushing parameter values at the stress level of interest.