Mandi: IIT researchers study climate risk to railway embankments

Mandi, April 20

Researchers at the IIT, Mandi, and Durham University, UK, have developed a suction monitoring setup for soil cyclic triaxial testing to investigate the impact of climate change on railway embankments.

Ashutosh Kumar, Assistant Professor, School of Engineering, IIT, Mandi, says that the main component of the railway infrastructure is trackbed, which is supported by earthworks. This is mainly used to support the track infrastructure and carry the load imparted by moving traffic.

“The present design protocols only consider the load developed due to moving trains, thereby ignoring the real case scenario of changing the natural state of the soil due to the ingress and egress of water. Oftentimes, soil used in earthworks is compacted and remains unsaturated during its lifetime. Seasonal variations in terms of precipitation and drought are capable of altering the amount of water present within this compacted soil mass, which can alter the strength of the embankment,” he adds.

He says, “To address the challenge of providing a sustainable and resilient transportation infrastructure under changing climatic conditions, the IIT, Mandi, is working closely with Durham University, UK. We all now understand the reality of climate change, which is causing intense rainfall”.

“Compacted soil is susceptible to deteriorate under changing climatic conditions due to changes in the water-holding capacity of the soil, causing hysteretic loss in the soil strength. Repeated train loading can exacerbate the deterioration process that will ultimately cause premature track degradation and result in failure,” he adds.

He says, “Understanding the coupled impact of train and environmental loading is essential to design and maintain the railway embankment against changing climatic conditions. Therefore, this study developed a setup within a cyclic triaxial apparatus to monitor changes in soil suction and deformation brought by traffic-induced cyclic loading and environmental loading, which can be used to assess climate risk at the design stage of railway embankments,” says Ashutosh.

He says that the soil sample used in the study was taken from a 650-km heavy haul South African coal line that connects around 40 mines to the Richards Bay Coal Terminal there.

“During research it was observed that the suction-monitoring setup can test the soil sample that has undergone seasonal variation either in the laboratory environment or field conditions. This will help to develop strategies to mitigate climate risk at the design stage of railway embankments, leading to more sustainable construction,” he adds.