Non-reflecting boundary used for simulating ground born vibrations caused by the moving train loads

Abstract

In the very early the problem of train induced ground vibrations has received considerable attention, due to the sever effect of wheel-rail interaction force on the railway infrastructures and nearby buildings. To predicate and mitigate such vibration problems, three dimensional finite element packages are most recently and widely used numerical method, although method of achieving non-reflecting boundary condition to avoid the boundary-related wave reflection is still problem. In most case, wide finite element models far from the field that is capable of minimizing the reflection is favored by researchers. However, modelling wide finite element mesh is time consuming and it is the most difficult issue to determine whether the cross-sectional model is sufficient. Thus, other schemes such as the material property of the non-reflecting soil model have to incorporate to minimize the size in the cross-sectional directions. Hence, a parametric study by using ABAQUS is conducted in this paper to identify the paramount important parameters of the soil that may affect the boundary-related wave reflection caused by the moving train loads. With this perspective, the finite element model is divided into two regions, called the near-field and far-field. The near-field includes the moving train loads and other geometric/material properties of the entire railway infrastructure represented by the finite element, while the far-field is covered the non-reflecting model placed at the truncated boundaries. To this end, a systematic study is carried out to examine the sensitivity of damping ratio, length, Young’s modulus and Poisson’s ratio of the boundary in suppressing the reflections. The results demonstrate the beneficial role of the boundaries and their parameters in suppressing the reflection, if the paramount important parameters are properly selected.