The Chenab Bridge, located in the Himalayan region of Jammu and Kashmir, is a remarkable feat of engineering, designed to withstand winds of up to 266 km/h and earthquakes of significant magnitude. Spanning the Chenab River at a height of 359 meters, it is the world’s tallest railway bridge and is vital for improving connectivity, promoting regional development, and enhancing India's strategic infrastructure in the region. It is not only an architectural marvel but also a challenge for engineers due to the unstable slopes it rests on. Constructed in the seismically active and geologically complex Himalayan region, the bridge had to overcome unique challenges like unstable rock slopes, landslides, and harsh weather.
A new study from the Indian Institute of Science (IISc) delves into the mechanisms of rock slope failures and the stability of the rock slopes supporting the Chenab Bridge. It combines various advanced analytical methods, field investigations, and engineering designs, to provide significant insights into addressing challenges posed by complex geological conditions in the region.
The Himalayan rock masses are highly complex because of the ongoing tectonic activity that continuously lifts and deforms the region. Rocks here are crisscrossed with joints, fractures, and faults that weaken their structure, making them prone to landslides and other failures.
To understand the complex structure, the study employed a combination of techniques to predict how the rocks behave under different conditions. Specifically, they employed; Kinematic Analysis, to Identify how rock blocks might slide or topple based on their orientation, Wedge Analysis, to determine where intersecting planes might create unstable blocks and, Finite Element Modeling (FEM) to simulate how stress and strain impact rock stability under different conditions.
By integrating these approaches, the researchers successfully identified both local and global failure risks.
The study emphasizes the value of modelling explicit joints in complex geological conditions. Jointed rock masses behave differently compared to homogeneous materials, and while traditional continuum models are useful for assessing global stability, they often overlook localized instabilities that can lead to significant failures. By explicitly incorporating joints into the analysis, the researchers could predict localized failures that might otherwise go unnoticed. This approach provided more realistic factors of safety and allowed engineers to design targeted reinforcement measures, such as rock bolts, to mitigate specific risks. This finding advocates for the adoption of advanced modelling techniques, such as FEM with explicit joints, in critical infrastructure projects.
The researchers also recommend using a hybrid approach that integrates continuum and discontinuum modelling for similar projects in challenging terrains. Additionally, they advocate for ongoing slope monitoring and regular model updates to reflect changes in geological and environmental conditions. This proactive approach ensures that critical infrastructure remains safe over its operational lifetime.
The study offers a robust framework for analyzing and stabilizing jointed rock slopes in highly complex geological environments. By leveraging advanced modelling techniques and targeted reinforcement, the research ensures the safety of the Chenab Bridge while providing valuable insights for future geotechnical projects.
This research news was partly generated using artificial intelligence and edited by an editor at Research Matters