Miniature cone tip resistance of sand with fly ash using triaxial setup

Abstract

In a continuation of the authors’ recent work, the ultimate tip resistance of a miniature cone using triaxial equipment was determined for samples of dry sand mixed with dry fly ash. The effect of (i) the proportion of fly ash, (ii) the relative density of samples, and (iii) the vertical overburden pressure was examined. It was noted that an addition of fly ash in sand for the same range of relative density leads to a significant reduction in the ultimate tip resistance of the cone (qcu). This occurs due to a decrease in the friction angle (ϕ) of the sample with an increase in the fly ash content for a given relative density. For ϕ greater than about 30°, two widely used correlation curves from published literature, providing the relationships between qcuand ϕ for cohesionless soils, were found to provide satisfactory predictions, even for sand – fly ash mixtures. As was expected, the values of qcuincrease continuously with an increase in the relative density of the soil mass and the vertical effective (overburden) stress on the sample.