Geotechnical Challenges and Adaptive Solutions in theNagdhunga Tunnel Construction Project

Abstract

The Nagdhunga Tunnel Construction Project in Nepal encountered a range of substantial geotechnical challenges, primarily due to the Himalayan region's complex and unpredictable geological conditions. Constructed using the New Austrian Tunneling Method (NATM), the project required significant adaptations to contend with collapses and sidewall deformation observed during excavation. Nepal’s geology, dominated by ongoing tectonic activity thrust faults, and highpressure metamorphic rocks, posing risks specific to
accretionary prism formed by plate collision. This experience highlights critical considerations for future underground infrastructure projects in Nepal and similar geologically active zones, particularly concerning geological complexity and logistical constraints related to material procurement.