NUMERICAL STUDY FOR HIGH SPEED RAILWAY TRACK FORMATIONS

Abstract

With the rising population around the world, traffic problems have now become more common than ever. Increase in traffic density and flow has crippled the existing modes of transportation. There is a growing need of improvement in the existing modes of transportation. As for Railways, there is an imminent need of improvement in the operating speeds and passenger carrying strength of existing trains. However, as the improvement in train’s operating speeds is sought out, it is equally important to give attention to the behavior of track foundations at higher moving train loads. Since high speeds and heavy train loads are accompanied by large vibration in the track structure which can possibly lead to train derailment and track damages. Therefore, to avoid such undesirable scenarios, it becomes very important to study to impact of high train speeds on the track foundation. Hence this study was carried out to investigate the response of track formation subjected to movement of high-speed trains. In this study, Finite element method was used to analyze the track formation for fast moving trains. A 3D Numerical model was prepared to represent the Indian railway track geometry. Numerical model was then subjected to moving train loads of Indian Semi High Speed train. Further, the model prepared was analyzed for displacement response of track foundation during passage of train at different speeds. The displacement response of track was studied and investigations were done to obtain critical speed for track section. Different track parameters were changed in the analysis to see their influence on the critical speed of track section. A reinforced track was also modelled using geogrid as reinforcement. The geogrid was placed at the interface of ballast and blanket layer. The effectiveness of geogrid as a reinforcement material for track formation was studied by comparing the track displacement response at different load frequencies. The impact of geogrid on the critical speed of track section was also evaluated. From the result, it was found that critical speed of a track system depends upon stiffness of subgrade, train geometry and track geometry. The reinforcement of track with geogrid was also found to have slight effect on the critical speed of the track system.