Shear Strength of Sands Reinforced with Polypropylene Fibers

The inclusion of oriented or randomly distributed discrete elements, such as fibers, to reinforce soil has recently attracted increasing attention in geotechnical engineering. The present paper studies the shear strength parameters of reinforced sands, consisting of different mean grain sizes. The polypropylene fiber volumetric content of the sands ranges from 0.1 to 0.5 %. Specifically, a series of direct shear tests were conducted to determine the peak and residual shear strength parameters of unreinforced and reinforced sands. Laboratory results showed that fiber reinforcement substantially improved the residual strength of fine sands of medium dense state. On the contrary, reinforced sands of high dense state appeared to exhibit negligible strength increment. Based on the experimental results, a non-linear regression analysis was performed to correlate the shear strength of reinforced sand with some descriptor variables.