Disturbed State Concept–Based Model for the Uniaxial Strain-Softening Behavior of Fiber-Reinforced Soil

Abstract

A uniaxial strain-softening constitutive model for fiber-reinforced soils is developed based on the disturbed state concept (DSC). The response in the relatively intact state is assumed to satisfy the Duncan–Chang model obtained from the prepeak stress–strain curve, while the fully adjusted state response satisfies the linear model obtained by an extension of the residual strength. The apparent stress–strain curve is a weighted average response derived from the two aforementioned response curves by a disturbance function that acts as the weight. The peak of the stress–strain curve and the postpeak stable point are assumed as the starting and ending points of the disturbance, respectively, which assign a reasonable physical sense to the parameters in the disturbance function. Comparisons of stress–strain curves and peak strength reveal that for a specified fiber, fiber content exhibits a greater influence on the reinforcement effect than fiber length. Five required parameters that vary with fiber content are used in the DSC model. Five sets of uniaxial compression test data of different fiber-reinforced soils are evaluated, and a high consistency between the stress–strain curves predicted by the DSC model and the test curves is noted. Both the consistency index δ and the energy absorption capacity reveal a satisfactory description of the fiber reinforcement effect.