Studies on Engineering Performance of Geogrid Reinforced Soft Subgrade

One of the preferred materials for construction of road embankments on soft subgrade soils being coarse grained soils. During the recent past utilization of geosynthetics has been increased to improve bearing resistance of weaker subgrades. Previous researches addressed the problems due to soft subgrade in several ways and provided solutions namely geosynthetics & coarse fill for construction on these soils insitu. However considering scarcity of fill material and cost of project a viable alternative can be bulk utilization of locally available weak soils. Neglecting construction difficulties etc., effective utilization is possible in small scale projects if engineering performance is enhanced. These improved soils can be used as fill over soft subgrades and adds benefit in the form of cost reduction. In the present study an attempt has been made to study the engineering performance (CBR) for different types of soil subgrades reinforced with geogrids. Tests are conducted on soil in lab and field and CBR value is determined. Studies are carried out and influence of parameters soil plasticity, geogrid tensile capacity, soaking and unsoaking on CBR property is examined. Enforced with geogrids and the performance of geogrids in soaked condition both lab & field are studied and the performance is quantified. The results obtained have shown the influence of plasticity & fines (%) and possible usage of geogrid in improving soaked CBR performance which in the absence of grid is very poor.