Improving Soil Stability by using Geo-Grid Made by Waste Plastic Material (I.e. Packaging Ribs)

Road pavements are vulnerable (weak) to soil performance because the foundation of the pavement is a roads most important element. And if the sub grade layer of pavement consists of expansive soil (black cotton soil), due to changes in moisture content and subsequent shrinkage and swelling, it undergoes failure. Thus, for the construction on such type of soil it is required to improve the engineering properties of soil or to replace the soil itself. Replacing the existing soil might not be a practical and feasible option, thus it is required to stabilize the soil with suitable stabilizer. However the selection of stabilizer depends upon the type of sub-grade soil, type of soil improvement desired, availability of stabilizer, the required strength and durability of stabilized layer, various stabilizing techniques, environmental conditions and the most important cost factor. This paper reviews the work of various researchers on stabilization of soil and use of geo-synthetic materials in improving its strength. The present study investigates the improvement in the bearing capacity of silty clay soil with thin sand layer on top and placing geogrids at different depths. Model tests were performed for a rectangular footing resting on top of the soil to establish the load versus settlement curves of unreinforced and reinforced soil system. The test results focus on the improvement in bearing capacity of silty clay and sand on unreinforced and reinforced soil system in non-dimensional form. The results show that bearing capacity increases significantly with the increased number of geogrid layers. The bearing capacity for the soil increases with an average of 16.67% using one geogrid layer at interface of soils.