Recently, a major collapse occurred in the under-construction Silkyara-Barkot tunnel. Located along the Yamunotri National Highway in the Uttarkashi district of Uttarakhand, the incident has trapped a significant number of workers, raising concerns about the safety measures in tunnel construction.
The Silkyara-Barkot tunnel is part of the ambitious Char Dham all-weather road project initiated by the Central Government. The Hyderabad-based Navayuga Engineering Company took over its construction on behalf of the National Highways and Infrastructure Development Corporation Ltd (NHIDCL).
Potential Causes for Tunnel Collapse
Although concrete reasons for the collapse are yet to be ascertained, it is speculated that a section of the tunnel, roughly 200-300 meters from the entrance, may have housed a fragile or brittle patch of rock that couldn’t be detected during the construction phase. Over time, water seepage through these weak spots might have diluted the area and led to the creation of an unseen cavity atop the tunnel structure, eventually causing the collapse.
Key Points in Tunnel Construction
Construction of tunnels involves several critical steps. These include excavation techniques such as Drill and Blast Method (DBM), which comprises drilling holes into the rock and detonating explosives to break it apart. Regions like Jammu & Kashmir and Uttarakhand largely rely on this method due to their challenging terrains.
Alternatively, Tunnel-Boring Machines (TBMs) can also be used; they function by drilling through rocks and simultaneously supporting the tunnel structure with precast concrete segments.
In addition to excavation methods, tunnel construction also requires comprehensive investigations of rock strength and composition via seismic waves and petrographic analysis. Moreover, constant monitoring using deformation meters and reliable support mechanisms are necessary.
Other Significant Tunnels in India
India boasts several significant tunnels, including the Atal Tunnel in Himachal Pradesh, which is the world’s longest tunnel above 10,000 feet. The Pir Panjal Railway Tunnel, running through the mountain range of the same name, is India’s lengthiest transportation railway tunnel at 11.2 km. The Jawahar Tunnel, or Banihal Tunnel, maintains year-round road connectivity between Srinagar and Jammu, while the Dr Syama Prasad Mookerjee Road Tunnel holds the record for being the longest road tunnel in India.
Steps Towards Safer Tunnel Construction
Furthering safety in tunnel construction calls for regular maintenance schedules including systematic inspections for structural integrity, drainage systems, and ventilation. Usage of sensors and monitoring technologies are critical to assess the structural health continuously.
Risk assessments conducted by third parties considering geological, environmental elements are also crucial, along with developing contingency plans and emergency protocols. Training personnel in tunnel management and implementing emergency response procedures can enhance safety measures.
Public awareness drives about safety protocols and reporting mechanisms can be beneficial. Advancements in technology could be employed for effective inspection and early detection of potential problems, with tools such as Artificial Intelligence, drones, or robots.
