Effect of Sand Gradation on The Behavior of Sand-Clay Mixtures

In contrast to the clean sands the behavior of sands with fines have complexities that has made it difficult for researchers to reach a general framework for their evaluation and this problem exist today for researchers. In this research work the effect of increasing clay content and also of the gradation of sand on the behavior and shear strength properties of over-consolidated mixtures of sand-clay was evaluated. one of the parameters of over-consolidated soils is the parameter m from the relationship of shear strength for over-consolidated clays. The compacted over-consolidated samples of mixtures of various sand gradations with 15, 20, 30 and 40 percent clay were tested in direct shear. the result showed that at a particular sand gradation, with the increase in clay content the shear strength and the value of m decreased. also at constant clay content with decrease in sand grains size the shear strength and vale of parameter m decreased.