Variation of the Groundwater Table within Indian Railway Embankments in Consideration of Climate Change

Abstract

Climatic changes have intensified heavy rainfall events in India, causing daily downpours from 156 to 594 mm, and these are expected to worsen in the future. This study analyses a double-line railway embankment using transient unsaturated–saturated seepage analysis through numerical modeling to examine the impact of rainfall scenarios, embankment height, initial groundwater table position, and soil water characteristics curves (SWCCs) of subgrade and subsoil. Our findings indicate an increased vulnerability of embankments to future rainfall due to rapid increases in the groundwater level, necessitating the requirement to make railway embankments resilient to climate change and thereby offering a sustainable mode of transportation. The groundwater onset mechanism across different heights remained consistent; rainwater infiltrated through side slopes first, rose near the toe, and then flowed horizontally, leading to convergence. The convergence level is affected by the SWCCs; however, a single normalized convergence plot can be created by presuming the horizontal flow of the infiltrated water through embankment and subsoil, irrespective of the material type, establishing horizontal flow as the principal convergence mechanism. In embankments over low-permeability subsoil, extremely heavy rainfall creates a unique pattern: side slopes and the top saturate early, while the saturation of the bottom central part is delayed. In such cases, deriving a groundwater variation curve might be challenging.