Effect of Shape of Footing on Coefficient of Elastic Uniform Compression of Polypropylene Fibre Reinforced Fine Sand

Abstract

Synthetic fibre reinforced granular soils, particularly fine to medium sands have the benefits of improved shear strength and permeability and as a result found wide application as fill and backfill material. However, not much work is reported on coefficient of elastic uniform compression (C_u) of fibre reinforced sand. C_u is used in determination of soil spring stiffness and is an important essential parameter in design of machine foundations and structures subjected to cyclic loads. Hence, in the present study, the effect of addition of polypropylene fibre in fine sand is assessed by conducting small scale cyclic load tests in the laboratory. The study is also intended to evaluate the effect of shape of loading plate on C_u of fibre reinforced sand. Fibres of 6 mm and 12 mm length in proportions of 0.5%, 1.0% and 1.5% by weight are mixed with fine sand in the study. The study yielded the optimum percentage of fibre for stabilization as 1%, with 12 mm fibre more effective than 6 mm fibre. No shape effect on C_u of fibre reinforced fine sand is observed in contrast to unreinforced fine sand for which C_u of circular plate is 0.85 times the C_u of square plate of same size