Expansive Subgrade Strength Improvement using Geogrid and Geotextile Layers

Abstract

Clay is fine grained soil, which is plastic due to its cohesive nature at relative moisture content. Clay soils exhibits alternate swell and shrink in variation with moisture content and possess low CBR value. In this study, stabilization of subgrade has been done by the introducing geosynthetics as layers. Non-woven geotextiles and geogrids layers are the geosynthetics used. Engineering properties such as shear strength and CBR value and index properties such as Atterberg limits and grain size distribution of the clay specimen are evaluated. CBR Test value obtained for control sample is 3.54 %, when the geogrid were placed at top & middle, CBR Values had been increased 4 % and 5.56 % respectively. The performance of Geogrid is increased when it placed together with geotextile as combined layer. CBR test conducted over the combined layers positioned at top and middle give the value 6.31 % and 6.9 % respectively.