Impact of extreme climate and train traffic loads on the performance of high-speed railway geotechnical infrastructures

High-speed railways are very important in global transportation. However, the railway subgrade is significantly affected by the environment due to its exposure to the atmosphere. At present, global warming is the primary trend in world climate change and seriously damages railway infrastructure. Owing to the coupling effect of extreme environmental and train loads, various subgrade problems tend to arise, such as settlement, ballast fouling, and mud pumping, thus inducing frequent railway accidents and reducing travel safety. Insights into the problems triggered by extreme climate and train loads are critical to the design and long-term operation of high-speed railway subgrades. This study therefore presents a detailed survey of recent advances in typical subgrade problems through analyzing the problem formation mechanisms and influences. Traditional and emerging detection/monitoring technologies in respect of subgrade problems are discussed in detail, as well as pre-accident and post-accident maintenance methods. Finally, according to the existing challenges in long-term subgrade shakedown assessment, an outlook on open opportunities is provided for future research.