Fiber-reinforcement of soils and stability analysis of reinforced foundation soils.

Abstract

Foundations, earth retaining walls, and embankments are all classified as earth structures. The stability of such structures can be improved by soil reinforcement. The reinforcement in the form of short fibers mixed-in with the soil is considered, and the yield condition for such a composite is developed. The preferred direction of orientation of fibers gives rise to anisotropy of the plastic properties of the fiber-reinforced soil. A mathematical description of yielding of fiber-reinforced soil is presented, and the kinematic approach of limit analysis is adopted to solve for limit loads on footings placed over such soils. The presence of anisotropy makes this analysis different from those attempted earlier. More traditional reinforcement in the form of sheets of geosynthetic material is also analyzed, and the bearing capacity of soils with combined fiber and planar reinforcement is addressed. A practical problem of a two-layer foundation soil, with a weak clay beneath a reinforced granular fill, is considered to illustrate the usefulness of the developed model for fiber-reinforced soil.