The Effects of Flooding Conditions on Dynamic Behaviour of Ballasted Railway Tracks

Abstract

Ballasted track is the most used track structure in Thailand, which are expanded nationwide due to their ease and speed of construction which make them a cost-effective solution for the railway industry. However, with global warming causing more volatile weather conditions and heavy rain, which leads to multiple occurrences of flooding in Thai railway structures. Therefore, the impact of flooding on the dynamic behaviour of the ballasted track structure should be investigated. Although the impact of flooding on the dynamic behavior of ballasted-track structure has been extensively studied, the effect of washed away conditions on sleeper mode shape and natural frequencies has not been thoroughly explored. This study found that the sensitivity of natural frequencies under loss of supporting layer varies for each fundamental mode, with lower modes being more sensitive. The natural frequency initially increases at 25% loss of support but then reduces to a similar value at a fully washed away condition prior to support loss. The first and second mode shapes are not significantly affected by the loss of support. However, for the third mode shape, if the supporting layer is asymmetrical, the mode shape will change due to the unevenness of the ballast layer.