Analysis of the Variations in Shear Strength of Reinforced Soil with Randomly Distributed Typha Fibers

Abstract

Geotechnical engineers has always strived to evade the manipulation of the environment by using and developing natural and artificial soil reinforcements which are not friendly with constructions and uploading. At one hand, utilization of natural fibers due to the factor of accessibility, adaptability with the environment and their reasonable costs of production has drawn attention and on the other hand the special feature of Typha in absorbing heavy metals has dedicated a noteworthy role for this plant in the environmental studies. The aim of this study is to investigate the efficacy of Typha fibers, a type of natural fiber, on the variations of the shear strength and changes in plasticity of the reinforced soil. In order to have a better perspective regarding the mechanism of the efficacy of fibers on the shear strength of soil, direct shear test was conducted on the samples of the reinforced soil in different weight percentages of fibers and in normal stresses of 100, 200, and 300 (kpa). Findings showed that addition of fibers to soil bring about increase in the level of cohesion and the friction angle of soil. With the increase in the stresses, vertical displacement variations will decrease. Increase in the percentage of the fibers reduces the plasticity of the sample along the shear plate which leads to the increase in the shear strength of soil.