A Research Investigation into the Impact of Non-Plastic Fine Particles on the Shear Strength Characteristics of Sand-Silt Mixtures

The engineering properties of sandy soil, specifically its ability to support structures, are significantly influenced by its composition, including the presence of fine particles (fines). While the relationship between certain soil properties like SPT N-value, internal friction angle, and density is well-understood for cohesionless soils, the impact of varying amounts of fines on sand behavior remains less explored. This research investigates the effects of non-plastic fines on the shear strength properties of sand-silt mixtures. It has also attempted to establish a relationship between the proportion of sand-silt mixture and shear strength. Sand used during the experimentation is classified as poorly graded (SP) as per the Unified Soil Classification System (USCS). Non-plastic fines are obtained locally, having liquid limit (LL) is 21.4%, plasticity index (PI) is less than 4 (PI