Liquefaction Resistance of Different Size/Shape Sand-Clay Mixtures Using a Pair of Bender Element–Mounted Molds

The aim of this study is to assess the influences of both the size and shape of sand grains mixed with a clay on shear modulus (Gmax)– and shear wave velocity (vs)–based liquefaction resistance (cyclic resistance ratio, CRR) using an intensive series of bender element (BE) tests. A low plasticity clay (CL) was added to two specific particle gradations (0.15–0.30 mm, and 1.0–2.0 mm) of clean sands with particular shapes (angular and rounded) at the percentages of 5, 10, 15, 20, 30, and 40, by dry weight. The BE tests were performed on the remolded specimens of different size/shape sands containing various amounts of CL in a recently designed mold used specifically for cohesionless soils, and then the values of vs, Gmax, and CRR were investigated. In most of the cases, the testing results indicated that, up to 20 % fines, which is named as transition fines content (FCt), Gmax and CRR values decreased, and then they increased for the specimens tested. Eventually, Gmax and CRR values of the specimens were significantly changed by the physical features (size, shape) of the sand grains with all the clay inclusions and frequencies applied.