Behaviour of fiber reinforced soil

The increasing value of land and the limited availability of sites for construction are greatly encouraging engineers to considered in situ soil improvement of weak soil deposits. Geotechnical engineers often encounter problems in designing foundations of structures on soft clayey soil. There may be a need for ground treatment to improve the bearing capacity of the soil. In granular soils in situ the soil may be very loose and indicate potential large elastic settlement. Under these conditions soils need to be densified to increase the unit weight and shear strength. The soil at a construction site or part thereof is not always totally suitable for supporting structures. In practice admixtures with fly ash, lime and geogrids are used frequently to stabilize soils and improve their load carrying capacity. Polypropylene fibers have been extensively used in civil engineering applications for many years. These fibers are used in concrete as a three dimensional secondary reinforcement. The influence of randomly oriented polypropylene fiber on the engineering behaviour of soil has not been reported to the same extent. Ease of application and reduction in cost are making this treatment more popular. The purpose of this investigation is to identify and quantify the influence of fiber variables (content and length) on performance of fiber reinforced soil specimens. In this study fibers were mixed with soft clay in various proportions (0%, 0.5%, 1.0%, 1.5% and 2.0%) to investigate the relative strength gained in terms of compaction, CBR, unconfined compression, etc. This paper presents a review of existing experimental and analytical work in this field and identifies other areas needing attention.