INVESTIGATION NUMERICAL BEHAVIOR STATIC AND DYNAMIC EMBANKMENTS OF RAILWAY CONSTRUCTED BY GEOFOAM

One of the most important problems related to performing railway on soft subgrade، is the problem of bearing capacity and embankment controlling settlement relied on these subgrades. The most provided concentrated solutions to solve this problem on improvement methods is based on ground soil such as compaction، injection، preloading، performing stone and cement columns. One of the new methods in which used in building way and roadway based on soft embankment used successfully، it can be mention to usage of light material of poly styrene or geofoam instead of soil in embankment. The literature show that till now there is no wide research about the possibility of using this material to build the embankment of Railway in soft subgrades. Therefore this research، focusing on two effective index on usage of Railway ballast on serviceability such as bearing and settlement embankmentand. To this end، with developing behavior model (hardening) specially geofoam material in finite difference software in FLAC2D، to investigated behavior of this material on ballast Railway embankment effected by static loading model of LM71and also Harmonic dynamic loading and as index out put، stability of embankment with difference heights and also the counter of their settlement is investigated، in additional to، by out puts from numerical model، using multivariable regression، the relation closed form analysis between settlement of static and dynamic with ductility، cohesion of ground، and ductility of geofoam parameters، embankment height and train axle load is derived. At final part، as for as the limitation in general settlement in rail way embankment، usage allowable domain of this material is drived.