Experimental Study on the Mechanical Behaviors of Loess Reinforced with Randomly Distributed Basalt Fiber

Abstract

Loess has the structural characteristics of porous, weakly cemented and under compacted, leading to its collapsible, disintegrative and dissolute features. To study the mechanical behaviors of basalt fiber-reinforced loess, consolidated undrained triaxial tests were carried out to investigate the effects of fiber length (FL), fiber content (FC) and cell pressure (σ3) on the shear strength. Based on the test results, a constitutive model considering the effects of the σ3, FL and FC was established using regression analysis, and the estimation method for the model parameters was proposed. The results show that the stress–strain curve of the unreinforced loess exhibited a strain-softening type, while the reinforced loess displayed a strain-hardening type. The peak strength of the reinforced loess was significantly higher than that of the unreinforced soil, and increased with increasing of FL, FC and σ3. Compared with the peak strength when FL was 8 mm, the peak strength increased slightly when the FL was 12 and 16 mm, respectively. The anchoring effect and bridging effect between soil particles and fibers improved the cohesion and friction of reinforced soil, resulting in the increment in the shear strength. The experimental results are in good agreement with the model predictions, indicating that the established model and the parameter estimation method are suitable for describing the relationship between the stress and strain of basalt-fiber-reinforced loess. The research results can provide guidance of the design and construction of fiber-reinforced soil in loess areas.