Numerical analysis of foundation type on the long-term performance of two types of railway track structures

Abstract

: The railway structures (ballasted and ballastless tracks) present several similarities. However, the structural behaviour of both structures, which includes its long-term performance, is different mainly because of its stiffness. In the substructure, the behaviour of the subgrade has influence on the long-term performance of the railway track structures. Considering that the permanent deformation in the geomaterials occurs due to its elastoplastic character when submitted to cyclic loading (such as the repeated passage of the trains), this article aims to analyze the long-term response of railway structures, evaluating the influence of the foundation type and considering the dynamic mechanisms (irregularities on the track). Therefore, this study analyses which railway track structure is more sensitive to the foundation type, comparing the accumulated settlements. The numerical framework adopted in this paper is based on 2.5D FEM-PML approach for the track-ground simulation, being the rolling-stock modelled using a simple multi-body approach. The long-term analysis is carried out using an empirical model based on laboratory experimental results, allowing the simulation of the behaviour of typical subgrade soils under repeated loading.