Finite Element Method for Improving Soft Soil Underneath a Ballast Railway Track

Abstract

It is always recommended to improve the properties of the soft soil beneath the railway networks often in such cases to increase its ability in bearing different applied loads and to control the expected generated settlements. The most methods used to improve the soil are by using ballast layers with or without a reinforced single geogrid layer or a geogrid layer at different spacing. This study presents a three-dimensional finite element analysis for soft soil underneath a ballast railway track by using a finite element program (ANSYS) which considers these days the software used in many engineering applications and most completeness. Twenty-four models were created using a nonlinear three-dimensional finite element to study the effect of ballast thickness, mechanical properties of soft soil (undrained shear strength and modulus of elasticity), and geogrid layer reinforcement to improve the soft soil. The ballast, soft soil, and steel plates were modeled by using an 8-nodes brick element with three degrees of freedom per node. While a 4-nodes Shell element with six degrees of freedom per node was used to represent the geogrid layer under and between ballast...