Influence of Particle Size and Gradation on Liquefaction Potential and Dynamic Response

Abstract

Centrifuge testing data are presented to elucidate the influence of particle size and gradation on liquefaction potential and dynamic response. The physical, index, and material properties of nine test soil mixtures, sharing a common geologic origin and ranging in D50 from 0.18 to 2.58 mm and Cu from 1.53 to 9.86, were quantified and compared to the range of values exhibited by clean sands in the literature. Each centrifuge model was subjected to 15 dynamic loading events across a range of relative density and Arias intensity levels. The high permeability of the poorly graded soils prevented flow liquefaction; however, the gap and well-graded soils generated excess pore pressures similar to clean sands even though large particles were present. Despite similar pore pressure responses, the gap and well-graded test soils exhibited lower cumulative volumetric strains than the clean sand because of enhanced dilation. The tendency for the gap and well-graded soils to dilate is theorized to stem from their enhanced packing efficiency and increased shear stiffness.