Particle Gradation and Liquefaction

Abstract

A study is presented on the resistance to liquefaction of sands with different gradations but identical mean grain size and mineralogy. Test specimens are reconstituted using a newly developed slurry deposition technique that yields not only homogeneous unsegregated specimens, but also simulates closely fluvial and hydraulic fill deposition processes. It is shown that with improved gradation, the cyclic strength at a given relative density increases in the range of lower relative densities but decreases in the range of higher relative density. In the range of loose relative densities, poorly graded sand develops strain as a consequence of contractive deformation in contrast to cyclic mobility for sands that are better graded. Thus, gradation may control the occurrence of contractive deformation and, hence, possible flow failure at low relative densities.