SECTOR | POWER, WATER & STORAGE
● TBMs are capable of safely constructing very deep and long tunnels with the installation of conventional rock support but with impacts of elevated in situ stresses;
Right, figure 15: Precast concrete segmental tunnel lining for Bheri Babai
PHOTO CREDIT: ROBBINS
● The most prudent approach for the construction of hydropower tunnels using TBMs in the Himalayas is in conjunction with precast concrete segmental lining which provides safety to workers from high in-situ stresses;
● Special design features/components, including high torque and thrust capacity, are required for TBMs to be successfully used in the Himalayas to cope with the challenges of the geotechnical conditions; and,
● Good planning and risk management practices have proven to be effective in contributing to the success of the use of TBMs in the Himalayas.
REFERENCES
● Armetti, G. and Panciera, A. (2023) ‘Risk management process for underground works.’ World Tunnel Congress (WTC) 2023, ITA-AITES; Athens, Greece.
● Brox, D. and Grandori, R. (2023) ‘Pre-Cast Tunnel Linings for Hydropower Tunnels: Advantages and Successes.’ WTC 2023; Athens Greece.
● Brox, D. and Piaggio, G. (2025) ‘High In-Situ Stresses in Deep and Long Tunnels: Risks and Impacts.’ WTC 2025; Stockholm, Sweden.
● Brox, D. (2022) ‘Melamchi Water Supply Tunnel Phase 1: Design and Construction Challenges.’ WTC 2022; Copenhagen, Denmark.
● Brox, D. (2021) Practical Guide to Rock Tunneling, 2nd Edition, Amazon Kindle. Pages 386.
● Brox, D. (2020) ‘TBM Risk Assessment and Selection for Hydropower Tunnels.’ WTC 2020; Kuala Lumpur, Malaysia.
● Brox, D. (2013) ‘Evaluation of Overstressing of Deep Hard Rock Tunnels.’ WTC 2013; Geneva, Switzerland.
● Brox, D. (2012) ‘Evaluation of Overstressing of Deep, Hard Rock TBM Excavated Tunnels in British Columbia.’ Tunnelling Association of Canada (TAC) Conference 2012; Montreal, Quebec.
● Clark, J. and Chorley, S. (2014) ‘The Greatest Challenges in TBM Tunneling: Experiences from the Field.’ North American Tunneling (NAT) Conference 2014; Los Angeles, US.
● Cooper, C. (2025) ‘Forging New Paths: The RVNL Package 4 Himalayan TBM Tunnel Revolution.’ Indian Tunneling Magazine.
● Dorji, T., Brox, D. and Wangdi, S. (2024) ‘Challenges and Lessons Learned from 100km of Major Hydropower Tunnels in Bhutan.’ WTC 2024; Shenzhen, China.
● Goel, R.K. (2014) ‘Tunnel Boring Machines in the Himalayan Tunnels.’ Indorock 2014: 5th Indian Rock Conference, 12-14 November 2014.
● Goel, R.K. (2016) ‘Experiences and lessons from the use of TBM in the Himalaya – A review. Tunnelling and Underground Space Technology (TUST), Vol 57, pp277-283.
● Grandori, R. (2016) ‘DSU TBM for Vishnugad Pipalkoti TBM Design Development for Large Diameter Rock Tunnels Under the high Covers of the Himalaya.’ WTC 2016; San Francisco, US.
● Grandori, R. De Biase, A., and D’Ambrosio, M. (2018) ‘Choice of TBM type for mountain tunnelling under very poor geological conditions: Hybrid, Slurry, EPB, DSU, Convertible TBMs.’ WTC 2018; Dubai, UAE.
● Harding, D. (2010) ‘Tunnel Boring Machines used for Irrigation in Andhra Pradesh, India.’ WTC 2010; Vancouver, Canada.
● Home, L. and Shrestha, A. (2023) ‘Use of a Tunnel Boring Machine on Nepal’s First and Second TBM-Driven Tunnels in Mountainous Terrain: Sunkoshi Marin and Bheri Babai Hydropower Projects.’ Hydro 2023, Edinburgh.
● Khali, R.K., and Potnis, S. (2023) ‘Construction of headrace tunnel of Vishnugad Pipalkoti HE Project (444MW) in extreme geological conditions: Issues and challenges - A case study.’ WTC 2023; Athens, Greece.
● Kumar, N, Varughese, A., Kapoor, V.K., and Dhawan, A.K. (2004) ‘In-Situ Stress Measurement and Its Application for Hydroelectric Projects - An Indian Experience in the Himalayas.’ Sinorock 2004 Symposium, Int. J. Rock Mech. Min. Sci., Vol. 41, No. 3.
● Mauriya, V.K., Yadav, P.K, and Angra, V.K. (2010) ‘Challenges and Strategies for Tunnelling in the Himalayan Region.’ Indian Geotechnical Conference – 2010, GEOtrendz, IGS Mumbai Chapter & IIT Bombay.
● Millen, B. and Brandl. J. (2011) ‘TBM recovery under high cover and extreme water-inflow, Himalayas, India.’ 1st International Congress on Tunnels and Underground Structures in South-East Europe, 2011; Dubrovnik, Croatia
● Millen, B., Gupta. V.K., and Brandl. J. (2010) ‘Tapovan Vishnugad hydroelectric power project – experience with TBM excavation under high rock cover.’ Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin; Geomechanics and Tunnelling 3, No. 5
● Panthi, K.K. (2009) ‘Appropriateness of open TBM tunnelling in the Himalaya – A case study.’ Eurock 2009: Rock Engineering in Difficult Ground Conditions – Soft Rocks and Karst, Ed. Vrkljan, I.
● Panthi K. K. (2012) ‘Evaluation of rock bursting phenomena in a tunnel in the Himalayas.’ Bulletin of Engineering Geology and the Environment, Vol. 71, pp. 761–769
● Peach, G., Ashcroft, B. Amici, R., and Mierzejewski, J. (2019) ‘Shotcrete Lining Installed from an Open Gripper TBM Remedial Works.’ WTC 2019; Naples. Italy.
● Swannell, N., Palmer, M., Barla, G., and Barla, M. (2016) ‘Geotechnical risk management approach for TBM tunnelling in squeezing ground conditions.’ TUST.
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