An analytical solution is presented for interpreting the coefficient of consolidation from piezocone dissipation tests in clayey and silty soils, based on principles of cavity expansion theory and critical-state soil mechanics. This solution accommodates the routine monotonic decay of porewater pressures with time associated with soft to firm to stiff silts and clays, as well as the noted dilatory responses (increase then decrease with time) observed in overconsolidated fissured materials