Numerical Analysis of Fiber-Reinforced Soils Based on the Equivalent Additional Stress Concept

Conventional numerical analysis methods for fiber-reinforced soils involve either cumbersome procedure or neglect of evolving fiber-soil interaction. In this paper, a new numerical analysis method is developed based on the equivalent additional stress (EAS) concept. Fibers' reinforcing effects are treated as compressive stress increments (CSIs) within soils conforming to the modified Cam-Clay (MCC) model. The radial and axial components of the CSIs are superimposed iteratively on the principal stress increments. A fiber constitutive model, a sliding function, and a spherical coordinates system are introduced, enabling the method to account for fiber plastic deformation and breakage, and imperfect fiber-soil bonding. An iterative routine is programmed to calculate the response of fiber-reinforced soils to triaxial compression. The calculated response is compared with the test results by the authors and the test and calculation results by other researchers, indicating that the method well captures the strength and deformation behavior of fiber-reinforced soils at different fiber orientation distribution forms and volumetric fiber concentrations, but slightly overestimates the internal friction angle and energy absorption capacity.