Particle shape effect on interfacial properties between granular materials and geotextile

Abstract

This paper presents an experimental study investigating the effect of particle shape of granular soils on the shear strength characteristics via direct shear tests. Thirty direct shear tests were conducted on spherical and crushed sand mixtures with different proportions (i.e. 0%, 25%, 50%, 75% and 100%). The overall regularity (OR) parameter of sand particles varies between 0.788 and 0.909, fairly reflecting the particle shape of sand mixture. A particular relation between OR and maximum shear strength was found, namely that maximum shear strength increases with a decrease in OR. Furthermore, a gradual increase was observed in the improvement factor (If) due to geotextile reinforcement with an increase in OR except for S25C75, representing 25% spherical and 75% crushed sand, at high and low normal stress levels (i.e. 29 kPa and 116 kPa). The interfacial friction angle (ϕ) of sand mixtures is improved by geotextile reinforcement. Additionally, geotextile reinforcement caused an apparent increase in ϕ with decreasing OR values.