Probabilistic analysis of randomly distributed fiber-reinforced soil

A series of triaxial compression tests were carried out on cohesionless soils reinforced with discrete, randomly distributed fibers, both synthetic and natural to study the influence of fiber characteristics (i.e., weight fraction, aspect ratio, and surface friction) soil characteristics and its density, and confining stress on shear strength of reinforced soils. A regression analysis of test results has been carried out to develop a mathematical model to bring out the effect of these factors on the shear strength of reinforced soil. The model estimates the strength of soils reinforced with any type of fiber and under given stress environment. The model predictions agree reasonably well with the experiment results and the results published in the-literature. The test results indicate that the failure envelopes of soil-fiber composites have a curvilinear failure envelope, with a transition occurring ata certain confining stress, termed as ''critical confining stress,'' below which the fibers tend to slip. The amount of the critical confining stress is affected by the fiber aspect ratio. Fiber inclusion increase significantly the shear strength of soil. The increase in strength is function of fiber weight fraction, aspect ratio and soil grain size.