Experimental Study on the Shear Behaviors of PolypropyleneFiber-Reinforced Sand

With excellent water permeability and high shear strength S, fiber-reinforced sand (FRS) is an ideal material for subgrades and has promising application prospects. In this study, the FRS were formed by adding the randomly distributed fibers to the sand specimens. Based on the triaxial consolidated drained tests, the effects of factors such as fiber content ζ, fiber length lf, relative density Dr and confining pressure σ3 on the S of FRS were systematically investigated. The test results showed that the S of the FRS increased as ζ, lf, Dr and σ3 increased. Under axial loads, the stress-strain curve of the FRS exhibited a hardening trend. Under specific Dr and σ3, the S increment of the FRS had a strong linear relationship with ζ and lf. The Mohr’s stress circle results showed that the FRS possessed not only frictional strength but also high cohesive strength. Based on the triaxial consolidated drained test results, the S of the FRS was calculated using the Zornberg model and Michalowski model. The calculation results showed that the S predicated by the Zornberg model differed significantly from the measured values. However, the S predicted by the Michalowski model were in good agreement with the measured values.