AN APPROACH STUDY OF REDUCING THE SUB-BALLAST THICKNESS OF RAILWAY USING GEOTEXTILES

: Railway transportation in Iraq is irreplaceable for its significant role in economic growth. Due to inadequate maintenance and upgrading of the railroad, the Iraqi transportation system has deformed and poor-quality rails. The ballasted track is the traditional railway system where the ballast and sub-ballast layers provide structural support against the high dynamic stresses transmitted from moving trains. This paper attempts to study the effect of geotextile reinforcement on railway-ballasted track layers using the Abaqus program to examine the behavior of railroads' railway-ballasted trucks of varying thicknesses reinforced with geotextile. The study used the finite element method and adopted simulation to investigate the behavior of the railways. The sub-ballast thicknesses used are 150, 200, 250, 300, 350, and 400 mm, with 200 mm ballast thickness and 4 m subgrade thickness. The findings revealed that a 50 mm increase in sub-ballast thickness resulted in a 7.2% reduction in deformation. The findings show that utilizing geotextile atop the ballast layer is equivalent to increasing the sub-ballast layer's thickness by around 3.57 cm to reduce track distortion. The result showed that using geotextile would reduce model settlement with a range between (38-18) percent for total model settlement for the different models that have been tested. In addition, using geotextile under the ballast layer is more effective in reducing model settlement if there is an economical restraint to use only one reinforcement layer.