Shear Strength Behavior of Fiber-Reinforced Soil: Experimental Investigation and Prediction Model

Abstract

This paper presents a prediction model for the shear strength of fiber-reinforced soil. A series of triaxial compression tests were first conducted to investigate the influences of fiber content and fiber length on the shear strength behavior of fiber-reinforced soil under different confining pressures. Experimental results on the stress–strain relationship, shear strength improvement ratio, shear strength parameters, and reinforcement mechanism are presented and discussed. Results indicate that the shear strength of fiber-reinforced soil increases significantly with increasing fiber content, but there exists an optimal value for strength improvement. The fiber content and fiber length have little influence on the friction angle of fiber-reinforced soil, while the apparent cohesion increases significantly with increasing fiber content and fiber length. Based on the experimental data, a prediction model was proposed for the shear strength of fiber-reinforced soil using the concepts of equivalent apparent cohesion and equivalent normal stress. The model can capture the decrease in shear strength improvement effect due to excessive fibers and can predict the shear strength of fiber-reinforced soil with good accuracy using fiber parameters and shear strength parameters of unreinforced soil.