Shear modules of claysand mixtures using bender element test

Abstract

Bender-element (BE) tests were conducted on clay-sand mixtures to investigate the variation of small strain-shear modulus (Gmax) with the sand content and the physical characteristics (size, shape) of the sand grains in the mixtures. Three different gradations (0.6–0.3 mm, 1.0–0.6 mm and 2.0–1.0 mm) of sands having distinct shapes (rounded, angular) were added to a low-plasticity clay with mixture ratios of 0% (clean clay), 10%, 20%, 30%, 40%, and 50%. For the purposes of performing a correlation analysis, unconfined compression (UC) tests were also carried out on the same specimens. The tests indicated that both the Gmax and unconfined compressive strength (qu) values of the specimens with angular sand grains were measured to be lower than those with rounded sand grains, for all sizes and percentages. As the percentage of sand in the mixture increases, the Gmax values increase, while the qu values decrease. The results further suggested that the Gmax values decrease as the qu values decreases as the size of the sand grains reduces.