Effect of random inclusion of sisal fibre on strength behaviour of soil

Construction of building and other civil engineering structures on weak or soft soil is highly risky on geo-technical grounds because such soil is susceptible to differential settlements, poor shear strength and high compressibility. Improvement of load bearing capacity of the soil may be undertaken by a variety of ground improvement techniques like stabilisation of soil, adoption of reinforced earth technique etc. Reinforced earth technique is considered as an effective ground improvement method because of its cost effectiveness, easy adaptability and reproducibility. Therefore, in the present investigation, sisal fibre has been chosen as the reinforcement material and it was randomly included in to the soil at four different percentages of fibre content, i.e. 0.25, 0.5, 0.75 and 1% by weight of raw soil. Four different lengths of fibre, i.e. 10, 15, 20 and 25 mm are also considered as one of the parameters of this study. The main objective of this investigation had been focused on the strength behaviour of the soil reinforced with randomly included sisal fibre. The reinforced soil samples were subjected to compaction and triaxial compression tests. The results of these tests have clearly shown a significant improvement in the failure deviator stress, Shear strength parameters (C and φ) of the studied soil. It can be concluded that sisal fibre can be considered as a good earth reinforcement material.