A Comparative Study on Shear Strength of Soil Using Geogrid and Geotextiles

Abstract

Failure of retaining walls, roads and collapse of soil have led geotechnical engineers to use reinforced soil to increase its strength. When the soil is unconfined and subjected to compressive stress, tensile stress are developed in the other direction. However if internal reinforcement layers are provided, frictional force is mobilized along the surfaces of the reinforcement layers and strength of the soil is considerably increased. It is a common practice among geotechnical engineers to use geosynthetics for soil reinforcement in various construction works. The major products of geosynthetics includes geotextiles, geogrid and geomembranes. Geogrids are used as reinforcement layers in retaining walls, embankments, road bases and below rail tracks. Geotextiles are used to separate different geomaterials and acts as filtration material to retain the soil particles. In the present study soil is collected from the bed of Solani River in Roorkee, India and soil classification is carried out on the unreinforced soil. Direct shear test is performed on unreinforced soil specimen and soil reinforced with geogrid and geotextiles (woven and non-woven) for different magnitudes of normal stress. It is observed that the shear strength parameters for geogrid reinforced soil are higher than that reinforced using geotextiles. Moreover, soil reinforced using non-woven geotextile is observed to have higher shear strength parameter than woven type. Hence the utility of geotextiles and geogrids as significant soil reinforcement materials to improve the shear strength parameters of unreinforced soil is highlighted in the present study.