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.
| Original language | English |
|---|---|
| Pages (from-to) | 101-116 |
| Number of pages | 16 |
| Journal | Transportation Infrastructure Geotechnology |
| Volume | 9 |
| Issue number | 1 |
| DOIs | |
| State | Published - Feb 2022 |
| Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.
Keywords
- Half tunnels
- Highway
- Himalayas
- Road extension
- Rock mass classification
- Stability
ASJC Scopus subject areas
- Environmental Engineering
- Civil and Structural Engineering
- Transportation
- Geotechnical Engineering and Engineering Geology