EFFECT OF GEOSYNTHETIC REINFORCEMENT IN UNPAVED ROAD USING STATIC & DYNAMIC CONE PENETRATION TEST

Abstract

Unpaved roads are largely constructed in rural, mining, and forest areas. They are economic and less labour extensive as compared to paved roads. However, they generally under-perform when subjected to heavy loads and high traffic volume. The major challenges related to unpaved roads are excessive rutting, surface deformation, and reduced serviceability, when built on soft subgrade soils. This leads to higher maintenance cost and compromises overall road safety. A comparative investigation was done using static and dynamic cone penetration test on soft subgrade with and without geosynthetic reinforcement. The geosynthetics compared in this study were geogrid and geotextile. These reinforcements were placed in the soil test section at 50- & 100-mm depths to determine their effects on load distribution & strength improvement. The results of the reinforced sections showed increased cone resistance value, decreased penetration depth, and increased stiffness compared to the unreinforced soil. In static cone penetration test the geogrid reinforced subgrade shows an increase of 225% cone resistance while 144% resistance is achieved using geotextile reinforced at 50 mm and 61.36% cone resistance while 41.09% resistance is achieved using geotextile reinforced at 100 mm when compared to unreinforced section. In dynamic cone penetration test the geogrid reinforced subgrade shows an increase of 300% cone resistance while 200% resistance is achieved using geotextile reinforced at 50 mm and 200% cone resistance while 166.67% resistance is achieved using geotextile reinforced at 100 mm when compared to unreinforced section. These improvements may contribute to durability of the road, lower maintenance costs, and better road safety. The study will help the field practitioners to efficiently place these reinforcements for suitable applications.