Rock mass characterization along the tunnel axis for Golen Gol hydropower project Chitral, Pakistan
Keywords:
Geology; Strength properties; Deformation modulus; Characterization of rock mass; Support systems.Abstract
The characterization of rock mass is an essential part of the preliminary engineering design in the field of civil and mining engineering. It is considered very beneficial when limited geological and geotechnical data of site is available. In the present research, the empirical methods i.e. Rock Mass Rating (RMR), Tunneling Quality Index (Q-System) and Geological Strength Index (GSI) classification systems for assessment and classification of rock mass along the axis of tunnel. These empirical methods were applied on the geological and geotechnical data collected along the axis of tunnel. The strength properties and intrinsic properties of rock samples, which are important for characterization, were determined in the laboratory. The rock mass along tunnel axis was characterized based on the empirical methods, intrinsic and strength properties of the rock mass. After characterization, the rock mass was divided into three geotechnical units i.e. GU-1, GU-2 and GU-3. Different support systems for each geotechnical unit were recommended to stabilize the tunnel. The conventional drilling and blasting technique was proposed for driving of the tunnel.
References
Biniawski, Z.T., 1989. Classifcation of Rock Masses for Engineering: The RMR System and Future Trends, USA.
Cai, M., 2011. Rock Mass Characterization and Rock Property Variability Considerations for Tunnel and Cavern Design. Rock Mechanics and Rock Engineering, 44, 379-399.
Cai, M., Kaisera, P.K., Unob, H., Tasakab, Y., Minamic, M., 2004. Estimation of rock mass deformation modulus and strength of jointed hard rock masses using the GSI system. International Journal of Rock Mechanics & Mining Sciences, 41, 3-19.
Geni, M., Basarir, A., Ozarslan, E., Bilir, E., Balaban, 2007. Engineering Geological appraisal of the rock masses and preliminary support design, Doorukhan Tunnel, Zonguldak, Turkey. Engineering Geology, 92, 14-26.
Google Earth map, 2016. Golen Gol Hydro Power Project Chitral location map, downloaded from myearthonline.blogspot.com/
Hashemi, M., Moghaddas, S., Ajalloeian, R., 2 010. Application of Rock Mass Characterization for Determining the Mechanical Properties of Rock Mass: a Comparative Study. Rock Mechanics and Rock Engineering, 43, 305-320.
Hoek, E., Diederichs, M. S., 2006. Empirical estimation of rock mass modulus. International Journal of Rock Mechanics & Mining Sciences, 43, 203-215.
Hoek, E., Kaiser, P.K., Bawden, W.F., 1993. Support of Underground Excavations in Hard Rock.
Marinos, V., Marios, P., Hoek, E., 2005. Gelogical strength index: applications and limitations. Bulletin of Engineering Geology and Environment, 55-65.
Rockscience, 2015,https:www.rocscience.com
Shen, J., Karakus, M., Xu, C., 2012. A comparative study for empirical equations in estimating deformation modulus of rock masses. Tunnelling and Underground Space Technology, 32, 245-250.
Sonmez, H., Ulusay, R., 2002. A discusion on the Hoek and Brown failure criterion and suggested modifications to the criterion verified by slope stability case studies. Bulletin of Earth Sciences, 77-99.
Sopac, E., Akgun, H., 2008. Engineering geological investigations and the preliminary support design for the proposed Ordu Peripheral Highway Tunnel, Ordu, Turkey. Engineering Geology, 96, 43-61.
Tahir, M., Mohammad, N., 2014. Prediction performance and generalization of the empirical estimation of rockmass deformation modulus based on rockmass classification systems. International Journal of Scientific Engineering and Technology, 3, 1488-1495.
Wahid, A., Mohammad, N., 2014. Rock Mass Characterization for Diversion Tunnels at Diamer Basha Dam, Pakistan– a design perspective. International Journal of Scientific Engineering and Technology, 3, 1292-1296.
Water and Power Development Authority (WAPDA), 2011. Geology and Geotechnics of Golen Gol Hydropower Project Chitral, Pakistan, 1-30.
