Abstract
Numerical modeling is a fine tool for the assessment of inaccessible zones or unforeseen conditions in geotechnical engineering. When modeling structures in rocks, the laboratory-determined properties must be factored as per rock mass classification. The joints present in rock mass can be utilized for assessment of wedges forming around the tunnels. Half tunnels or overhanging tunnels are constructed in steep rock slopes through slot cutting. This develops overhanging cliff in hard rocks that looked like a half tunnel. Half tunnels have advantage over conventional tunnels or open excavations as they require less excavation. The current construction practice of half tunnels is solely based on experience of construction in hard rock. This study discusses the stability of half tunnels and analyzes its design in the Himalayas. A road extension case study for existing 7-m span tunnel is modeled and studied. Finite element code is used to assess the stability of half tunnels by analyzing different possible scenarios. In addition, rock mass classification is performed along with wedge analysis, and analytical designs. It was found that massive rock mass is quite suitable for the construction of half tunnels. Also, most economical and stable half tunnel designs were recommended.
Recommended Citation
M. Z. Emad et al., "Optimum Design Of Half Tunnels For Transportation In The Himalayas," Transportation Infrastructure Geotechnology, vol. 9, no. 1, pp. 101 - 116, Springer, Feb 2022.
The definitive version is available at https://doi.org/10.1007/s40515-021-00162-x
Department(s)
Mining Engineering
Keywords and Phrases
Half tunnels; Highway; Himalayas; Road extension; Rock mass classification; Stability
International Standard Serial Number (ISSN)
2196-7210; 2196-7202
Document Type
Article - Journal
Document Version
Citation
File Type
text
Language(s)
English
Rights
© 2025 Springer, All rights reserved.
Publication Date
01 Feb 2022
