Shear Strength Response of Fibre Reinforced Chlef (Algeria) Silty Sand: Laboratory Study

Algeria, like other Mediterranean countries, is highly exposed to seismic hazards. Several damages have been observed in previous earthquake such as, differential settlements of structures many slope failures and soil movements in Chlef region. This paper presents the results of a series of direct shear laboratory tests on medium fibre reinforced silty sand, highlighting the effect of including fibre content as reinforcement (0.1, 0.25, 0.3 and 0.5% as a fibre volumetric content). The results are analysed and compared with those of unreinforced sand. The tests are carried out for two soil sample states: dry and wet state with a water content of 3%. The experimental results show a clear improvement in the mechanical characteristics with the addition of polyester fibres especially for wet specimens. The fibre addition makes possible to improve not only the shear strength of the soil, but also reduces the volumetric change for a given stress loading, which can contribute to a limitation of the extension-contraction cracks of the soil samples. The percentage of fibres addition is an important parameter which presents an optimum of 0.25% for the undertaken study.