NUMERICAL ANALYSIS OF RAILWAY FORMATION WITH GEOGRID REINFORCED BALLAST AND BLANKET LAYER FOR HIGH-SPEED RAIL

Abstract

India will launch a high-speed rail project to improve the travel time between cities in the upcoming years. Upgrading its current speed of 180 km/h to a high speed of 360 km/h will be a turning point in railway transportation. The Vande Bharat Express is the current high-speed train that travels at a speed of 180 km/hr. India intends to start its first bullet train by 2026. But as the travel speed increases, the stresses will increase on the existing soil formation. The strains on India's railway subgrade component would significantly rise with the addition of high-speed railways and bullet trains. The strains may cause failure in more brittle soil. For thousands of years, soils are mixed with different fibers, fabrics, and vegetation to improve quality and stability. Geosynthetics which are polymer products are used in Civil engineering for decades. Utilizing geo-synthetics in the lengths of currently weak formations is an alternate strategy to reduce the number of stress. This paper gives a numerical analysis of the behavior of railway embankments built on sand. Finite element software was used to simulate the model. Using the finite element software PLAXIS 3D, a railway embankment's vertical deformations and stresses are calculated under a moving train load of 90 kN. The speeds of the moving train are taken as 180 km/h and 360 km/h for the modeling. Geogrid is installed as per the recommendations by RDSO (2018). The blanket layer and ballast layer are reinforced with geogrids at different depths. It was observed that on using geogrid in the different layers, the deformations and the stresses could be reduced up to certain levels. After analyzing the model, it can be concluded that Geogrids are beneficial in restricting the deformations and the stresses at particular sections but further studies are required to check the suitability of geogrids for the long run.