ABSTRACT
The development of underground infrastructure in densely populated urban areas presents significant geological challenges. This case study examines the geotechnical complexities encountered during the construction of the Nabi Karim Metro Station in Delhi India, managed by Delhi Metro Rail Corporation Limited (DMRC). Excavation to depths of 30 meters revealed intricate geological formations that were more complex than initially anticipated, leading to the failure of the original stabilization and retention scheme. Detailed site inspections highlighted discrepancies in the initial borehole data, particularly the presence of thicker mica schist bands. Despite the quartzite’s high unconfined compressive strength (UCS), its extreme fragmentation rendered traditional rock bolting ineffective. This paper analyzes the reasons behind the stabilization scheme’s failure and presents revised methodologies that enhanced excavation efficiency and improved geotechnical risk management in urban underground construction.
