Behavior of square footing on dune sand reinforced with nylon fiber

Abstract

Dune sand covers a large part of the world's desert. It is uniformly graded fine sand deposited by wind action. Geotechnical engineers face various problems in dealing with such soils as it has poor bearing capacity, high permeability and low shear strength etc. Reinforcing the soil with randomly distributed discrete fibers increases the shear strength of granular soil. The present paper deals with the laboratory tests on the use of nylon fibers as a means to enhance the bearing capacity of dune sand. A series of load tests were conducted on a mixture of dune sand and nylon fiber to determine various factors which influence the bearing capacity of dune sand nylon fiber mixtures. The amount of nylon fiber, added to dune sand, as 0.5%, 1.0%, 1.5% and 2%. The size of square footing and depth up to which nylon fiber were mixed varied and the load settlement behavior of square footings on dune sand reinforced with nylon fiber were recorded. The results of settlement behavior were interpreted with bearing capacity characteristics, bearing capacity ratio, settlement characteristics at constant load intensity and load intensity at constant settlement. The ultimate bearing capacity of dune sand reinforced with nylon fiber increases with nylon fiber content. Also, the ultimate bearing capacity increases with <i>H/B</i> ratio, where <i>H</i> is height of reinforced soil and B is the width of square footing.