REINFORCEMENT EFFECT OF GEOGRID IN THE BALLAST AND SUB- BALLAST OF THE RAILWAY TRACK

Abstract

The railway transportation in Iraq is essentially irreplaceable for its significant role in economic
growth through revenue derived from the movement of goods and raw materials and passengers between Iraq
main cities. The objective of this paper is to study the effect of geogrid reinforcement on railway tracklayers
through the use of Abaqus program. The ABAQUS program was considered as multipurpose modeling
program, the program cannot only solve the stress-strain problems but also other parameters like heat transfer,
Contact, dynamics, and electromagnetics. The model dimensions are (800*800*600 mm), subgrade layer is
400 mm thick and sub-ballast layer and ballast layer are 100 mm thick. Some laboratory testing was carried
out to determine the materials properties that were used as inputs for the finite element Abaqus program. The
tested models are an unreinforced model, sub-ballast reinforced model, and ballast reinforced model and a
double reinforced model consisting of geogrid reinforcement in the sub-ballast layer and ballast layer. The
result showed that using reinforcement layer would reduce model settlement with a range between (38-18)
percentage for total model settlement for the different models that have been tested. In addition, it is obvious
that use of geogrid under the ballast layer is more effective to reduce model settlement if there is an economical
restraint to use only one layer of reinforcement.
Keywords: Railway, Abaqus, Geogrid, Reinforcement, settlement.