Construction of Cross Passages and Underground Substations in Hard Rock Using Controlled Blasting Techniques Adjacent to Segmental Linings: A Case Study from the Rishikesh-Karnaprayag Railway Tunnel Project (RVNL Package-04)

The construction of cross passages and underground sub-station in hard rock formations presents significant engineering challenges in rugged Himalayan terrain, particularly when working in proximity to pre-installed segment linings. This paper explores the methodologies and best practices for executing such projects, with a focus on controlled blasting techniques. Controlled blasting is a critical tool to manage rock fragmentation and minimize vibrations that could compromise the integrity of nearby structural elements.

Key considerations include geological assessments to understand rock mass behaviour, precise blast design to optimize fragmentation, and advanced monitoring systems to mitigate risks. Case studies from Rishikesh-Karanprayag Railway Tunnel project, Uttarakhand, India highlight the effectiveness of these strategies in maintaining safety and structural stability. The findings provide valuable insights for tunnelling professionals aiming to balance efficiency with the preservation of tunnel integrity in complex geological settings.