Tensile strength and deformation properties of fiber-reinforced loess: Laboratory and numerical investigation

Abstract

The lower tensile strength of loess is an important cause of geohazards such as landslides and ground fissures in loess areas. In this study, the uniaxial tensile tests were conducted on basalt fiber-reinforced loess based on the digital image correlation method (DIC). Moreover, the discrete element method (DEM) was used to investigate the local microscopic mechanism of fiber-particle interaction. Results show that both the peak stress and the peak strain of loess were enhanced after fiber reinforcement. Brittle fracture was observed in unreinforced samples while ductile failure in fiber-reinforced ones with certain residual strength. The uniaxial tensile strength (UTS) of fiber-reinforced samples shows inverted U-shape changes with fiber content and fiber length, with the optimal reinforcement effect at fiber content of 0.6% and fiber length of 12 mm. The failure strain of loess increases after fiber reinforcement, which varies consistently with that of UTS. The maximum axial strain in the surface strain field declines first and then grows with the increase of fiber content and fiber length. More uniform deformation and pronounced plasticity were noted under the optimal fiber condition. The UTS of fiber-reinforced soil is about 1/5 of the uniaxial compressive strength (UCS). A UCS-based prediction model for fiber-reinforced loess was proposed and verified to estimate the UTS effectively. DEM simulation's force chain and displacement field results demonstrate the strength and deformation mechanism of reinforced loess with fiber content and fiber length.