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IJSTR >> Volume 7 - Issue 1, January 2017 Edition



International Journal of Scientific & Technology Research  
International Journal of Scientific & Technology Research

Website: http://www.ijstr.org

ISSN 2277-8616



Analysis Of Tunnel Squeezing Phenomenon In Hydropower Project

[Full Text]

 

AUTHOR(S)

Season Maharjan

 

KEYWORDS

Tunnel, Squeezing, deformation, rock mass, case study, Hydropower projects, Himalayas.

 

ABSTRACT

The challenges in underground excavation depends upon rock mass strength, method of excavation and stress and deformation behavior of rock. It is important to obtain reliable estimates of these problem as early as possible in order to carry out construction with least difficulties. Squeezing is one of the common problems in excavation in Himalayan region where weak rock mass moves radially inward leading to decrease in size of excavated portion. Different methods has been used for the estimation of potential squeezing phenomenon. As rock consists of complex formations and exhibit a wide range of behaviors, the analytical methods provided some approximate solutions only. For the simulation of deformation and support behavior, numerical approach has been carried out for the case study of Ankhu Khola Hydropower Project (42.9MW). RMR and Q-Value were found to be poor to fair for Phyllite schist with overburden varying from 49 m to 613m for headrace tunnel of the same project. Consequently, support system has been designed for the potential squeezing sction.

 

REFERENCES

[1] Shrestha, G.L., 2006. Doctoral Thesis. Stress induced problems in Himalayan tunnels with special reference to squeezing, Norwegian University of Science and Technology, Trondheim, Norway.

[2] Dube, A. K., Singh, B. and Singh, Bhawani (1986). Study of squeezing pressure phenomenon in tunnel Part-I and Part-II. Tunneling and Underground Space Technology, 1(1), 35-39 (Part-I) and 41-48 (Part-II), U.S.A

[3] Singh, B., Jethwa, J., Dube, A. and Singh, B., 1992. Correlation between observed support pressure and rock mass quality. Tunneling and Underground Space Technology.

[4] Goel, R., Jethwa, J. and Paithankar, A., 1995. Indian experiences with Q and RMR systems. Tunneling and Underground Space Technology.

[5] Jethwa, J.L. and Singh, B. (1984), “Estimation of ultimate rock pressure for tunnel linings under squeezing rock conditions – a new approach”, in Brown, E.T. and Hudson, J.A. (Eds),Design and Performance of Underground Excavations, ISRM Symposium, Cambridge ,pp. 231-8

[6] HSL, (2016) Feasibility Study: Main Report Volume 1, Hydro Solution Pvt. Ltd., Kathmandu,

[7] Carranza-Torres, C. and Fairhurst, C., 2000. Application of the Convergence-Confinement method of tunnel design to rock masses that satisfy the Hoek-Brown failure criterion. Tunneling and Underground Space Technology.