Particle shape effect on the interfacial properties between granular materials-geotextile

This paper presents an experimental study investigating the particle shape effect of granular soils on the shear strength characteristics via direct shear tests. In this direction, 30 direct shear tests were conducted with spherical and crushed sand mixtures with different proportions (i.e., 0%, 25%, 50%, 75%, and 100%). 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 that maximum shear strength increases with a decrease in the OR was found. Furthermore, a gradual increase was realized in the improvement factor (If) due to geotextile reinforcement with an increase in the OR except for S25C75, representing 25% spherical and 75% crushed sand, at high and low normal stress levels (i.e., 29kPa and 116kPa). The interfacial friction angle (ϕ) of sand mixtures is improved by geotextile reinforcement. Additionally, geotextile reinforcement caused an apparent increase in the ϕ with decreasing OR values.