Tests of geosynthetics-reinforced ballast stressed state under heavy trains

Abstract

Nowadays requirements for strength and stability of railway subgrade are increased. It occurs due to raising of train speed and axle load. Some sections of subgrade that were previously considered stable do not satisfy safety requirements. In this regard, superstructure reinforcing solutions need to be developed. This paper highlights ballast and subgrade reinforcement applications of geogrids in railway infrastructure. In recent years, geosynthetics are widely used for this purpose. The paper describes recent studies, which helped to identify geosynthetics reinforcement influence on ballast layer and subgrade. Influence of axial load on stress in ballast and subgrade was determined. Obtained data showed that design solutions are required to provide subgrade top bearing capacity in terms of operation with axle loads over 220 kN. Design solution is protective layers installation of polystyrene or geogrids. Five types of geosynthetic materials were placed on the top of subgrade to study vertical stresses distribution in ballast under freight train.