Radoslaw L. Michalowski

Anisotropy of fiber-reinforced soil

Fiber reinforcement is a technology to improve the strength of backfill in geotechnical structures.  The distribution of orientation of fibers is typically characterized by a preferred bedding plane.  This project focused on the development of an anisotropic yield condition for fiber-reinforced sand.  An interesting implication of anisotropy was found to be a lack of uniqueness in the internal friction angle along a shear surface with given orientation.  The anisotropic internal friction angle was found to be a function of the major principal strain rate direction, and not just a function of the orientation of the shear surface.  The variation of the internal friction angle as function of the major principal stress direction is illustrated in Fig. 1.