Numerical Simulation Study on the Applicability of Lightweight Foamed Soil Backfill of Railway Bridge Structure under Train and Seismic Impacts

摘要

The sudden bump at the transition area from the bridge usually cultivates to vigorous railway deterioration because of the variation in the railway's supporting foundation. Therefore, this study focuses on the development of an advanced lightweight backfill material that can resolve the serious settlement in the transition zone. Besides, due to the strict soil properties requirements for construction, some excavated local soils are not preferred. This issue leads to the expansion in the construction budgets and the consumption of natural resources. In this research, the usage of excavated locally silty soil can mitigate this issue. To improve the self- leveling of fresh material and further broaden the range of applications, the air-foam technique is integrated into this material with a ratio of 10 by volume. The resilient modulus test was conducted to investigate the engineering characteristic of the backfill mixture. The reinforcing effect of the lightweight backfill was then evaluated through the numerical simulation method under repeated train loads and earthquakes. Overall,the laboratory and the simulation results suggest a potential application of lightweight soil as a sustainable material since this material can substantially enhance the durability of the railway structure and provide smoothness for train operation.