A Mechanism-Based Shear Strength Theoretical Model for Fiber-Reinforced Cemented Soil

Fiber-reinforced soil is a multiphase and multiscale geomaterial and its strength is determined by the properties of the heterogeneous substances of soil and fibers and their coupling interaction mechanical responses. Based on the physical effects such as cohesion and friction generated by the interactions between soil particles and fibers, a fiber-soil cell element was constructed to investigate the influence of fiber characteristics on the shear strength of fiber-reinforced soil. This cell element is capable of describing the internal material information and fiber characteristics of fiber-reinforced soil. Moreover, according to the compatible geometry deformation between the fiber and soil at the microscale, the notion of strain gradient was introduced, and a multiscale and hierarchical fiber-soil cell element model was proposed. Furthermore, a series of unconfined compression tests are conducted to investigate the strengthening effect of fibers on soil, and the theoretical parameters of the proposed model are quantitatively investigated. Results show that the yield stress of fiber-reinforced soil increases with an increase in the length and content of the fiber. The yield stress of fiber-reinforced soil predicted by the proposed fiber-soil cell element model is in good agreement with that of the test result. The research results are significant for the development of a mechanism-based theoretical framework that links different coupling scales.