Construction of Mahadevtar Tunnel and Challenges Faced During its Stabilization

Authors

  • Pramod Krishna Adhikari Civil Engineer/Project Coordinator, China State Construction Engineering (CP1, KTFT)
  • Pragati Adhikari Senior Engineering Geologist, China State Construction Engineering (CP-1, KTFT)
  • Zhang Bo Deputy Project Manager, China State Construction Engineering (CP-1, KTFT)
  • Chen Ping Chief Engineer, China State Construction Engineering (CP-1, KTFT)

DOI:

https://doi.org/10.3126/ktftj.v4i1.70451

Keywords:

Mahabharat thrust, sequential excavation method, new Austrian tunnelling method, rock mass rating, kinematic analysis, shear zone, faults, joints, formation, deformation, muck

Abstract

The Madadevtar tunnel, constructed by China State Construction Engineering Corp. Ltd. as the main contractor for Package 1, is situated in a lithology comprising rock from the Upper Nawakot and Bhimphedi Group. These rock successions are separated by the Mahabharat Thrust. The excavation method employed is the New Austrian Tunnelling Method (NATM), resulting in two fully lined tubes. During design and construction, variations in rock composition were encountered. Similarly, the expected support types for detailed design and construction also exhibited some diversity. Challenges during construction included weathered and jointed rock masses, fault and shear zones, and groundwater inflow. Overbreak and collapses occurred due to weak rock and joint conditions. Addressing these issues involved installing additional ribs, rock bolts, grouting, and replacing sections in some parts of left and right tunnels.

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Published

2024-10-04

How to Cite

Adhikari, P. K., Adhikari, P., Bo, Z., & Ping, C. (2024). Construction of Mahadevtar Tunnel and Challenges Faced During its Stabilization. KTFT Journal, 4(1), 217–225. https://doi.org/10.3126/ktftj.v4i1.70451

Issue

Section

Research Articles