Document Type : Original Research Paper

Authors

1 Department of Mining Engineering, Balochistan University of Information Technology Engineering and Management Sciences, Quetta, Pakistan

2 School of Materials and Mineral Resources Engineering, University Sains Malaysia, Engineering Campus, Nibong Tebal, Penang, Malaysia

3 Department of Mining Engineering, Karakoram International University, Gilgit, Pakistan

4 Department of Sustainable Advanced Geomechanical Engineering, Military College of Engineering, National University of Sciences and Technology, Risalpur, Pakistan

5 Department of Mining Engineering, Institute of Technology Bandung, Indonesia

6 Department of Mining Engineering, Karakoram International University, Gilgit, PakistanUniversiti Technologi Malaysia

10.22044/jme.2022.12231.2219

Abstract

Support design is the main goal of the Q and rock mass rating (RMR) systems. An assessment of the Q and RMR system application in tunnelling involving high-stress ground conditions shows that the first system is more appropriate due to the stress reduction factor. Recently, these two systems have been empirically modified for designing the excavation support pattern in jointed and highly stressed rock-mass conditions. This research work aims to highlight the significance of the numerical modelling, and numerically evaluate the empirically suggested support design for tunnelling in such an environment. A typical horse-shoe-shaped headrace tunnel at the Bunji hydropower project site is selected for this work. The borehole coring data reveal that amphibolite and Iskere Gneiss are the main rock mass units along the tunnel route. An evaluation of the proposed support based on the modified empirical systems indicate that the modified systems suggest heavy support compared to the original empirical systems. The intact and mass rock properties of the rock units are used as the input for numerical modelling. From numerical modelling, the axial stresses on rock bolts, thrust bending moment of shotcrete, and rock load from modified RMR and Q-systems are compared with the previous studies. The results obtained indicate that the support system designed based on modified version of the empirical systems produce better results in terms of tunnel stability in high-stress fractured rock mass conditions.

Keywords

[1]. Mirza, U.K., N. Ahmad, T. Majeed, and K. Harijan. (2008). Hydropower use in Pakistan: past, present and future. Renewable and Sustainable Energy Reviews, 12(6): p. 1641-1651.
[2]. Carter, T. (Year of conference). Himalayan Ground Conditions challenge innovation for successful TBM Tunnelling. in Invited paper in Proc. Hydrovision India 2011 Conf, Delhi. SESSION 5c:(Risk Management in Tunnelling), 20pp.
[3]. Panthi, K.K. (2012). Evaluation of rock bursting phenomena in a tunnel in the Himalayas. Bulletin of Engineering Geology and the Environment, 71(4): p. 761-769.
[4]. Palmstrom, A. and H. Stille. (2007). Ground behaviour and rock engineering tools for underground excavations. Tunnelling and Underground Space Technology, 22(4): p. 363-376.
[5]. Stille, H. and A. Palmström. (2008). Ground behaviour and rock mass composition in underground excavations. Tunnelling and Underground Space Technology, 23(1): p. 46-64.
[6]. Sharma, H. and A. Tiwari. (2012). Tunnelling in the Himalayan Region: geological problems and solutions. International Water Power and Dam Construction, 64(9): p. 14-19.
[7]. Rehman, H., A.M. Naji, K. Nam, S. Ahmad, K. Muhammad, and H.-K. Yoo. (2021). Impact of construction method and ground composition on headrace tunnel stability in the Neelum–Jhelum Hydroelectric Project: A case study review from Pakistan. Applied Sciences, 11(4): p. 1655.
[8]. Rehman, H., A.M. Naji, J.-j. Kim, and H. Yoo. (2019). Extension of tunneling quality index and rock mass rating systems for tunnel support design through back calculations in highly stressed jointed rock mass: An empirical approach based on tunneling data from Himalaya. Tunnelling and Underground Space Technology, 85: p. 29-42.
[9]. Hoek, E. (2001). Big tunnels in bad rock. Journal of Geotechnical and Geoenvironmental Engineering, 127(9): p. 726-740.
[10]. Rehman, H., W. Ali, A. Naji, J.-j. Kim, R. Abdullah, and H.-k. Yoo. (2018). Review of Rock-Mass Rating and Tunneling Quality Index Systems for Tunnel Design: Development, Refinement, Application and Limitation. Applied Sciences, 8(8): p. 1250.
[11]. Barton, N., R. Lien, and J. Lunde. (1974). Engineering classification of rock masses for the design of tunnel support. Rock mechanics, 6(4): p. 189-236.
[12]. Bieniawski, Z.T., Engineering rock mass classifications: a complete manual for engineers and geologists in mining, civil, and petroleum engineering. 1989: John Wiley & Sons.
[13]. Celada, B., I. Tardáguila, P. Varona, A. Rodríguez, and Z. Bieniawski. (Year of conference). Innovating tunnel design by an improved experience-based RMR system. in World Tunnel Congress. Proceedings… Foz do Iguaçu, Brazil.
[14]. Barton, N. (2002). Some new Q-value correlations to assist in site characterisation and tunnel design. International journal of rock mechanics and mining sciences, 39(2): p. 185-216.
[15]. Marinos, P. and E. Hoek. (Year of conference). GSI: a geologically friendly tool for rock mass strength estimation. in ISRM international symposium. OnePetro.
[16]. Rehman, H., J.-J. Kim, and H.-K. Yoo. (Year of conference). Stress reduction factor characterization for highly stressed jointed rock based on tunneling data from Pakistan. in World Congress on Advances in Structural Engineering and Mechanics (ASEM17). Seoul, Korea.
[17]. Lee, J., H. Rehman, A. Naji, J.-J. Kim, and H.-K. Yoo. (2018). An Empirical Approach for Tunnel Support Design through Q and RMi Systems in Fractured Rock Mass. Applied Sciences, 8(12): p. 2659.
[18]. Pinheiro, M., X. Emery, T. Miranda, L. Lamas, and M. Espada. (2018). Modelling Geotechnical Heterogeneities Using Geostatistical Simulation and Finite Differences Analysis. Minerals, 8(2): p. 52.
[19]. Feng, X.-T. and J.A. Hudson, Rock engineering design. 2011: CRC Press.
[20]. Lak, M., M. Fatehi Marji, A. Yarahamdi Bafghi, and A. Abdollahipour. (2019). Discrete element modeling of explosion-induced fracture extension in jointed rock masses. Journal of Mining and Environment, 10(1): p. 125-138.
[21]. Zhou, F., V. Sarfarazi, H. Haeri, M.H. Soleymanipargoo, J. Fu, and M.F. Marji. (2021). A coupled experimental and numerical simulation of concrete joints' behaviors in tunnel support using concrete specimens. Computers and Concrete, 28(2): p. 189-208.
[22]. Haeri, H., V. Sarfarazi, P. Ebneabbasi, A. Shahbazian, M.F. Marji, and A. Mohamadi. (2020). XFEM and experimental simulation of failure mechanism of non-persistent joints in mortar under compression. Construction and Building Materials, 236: p. 117500.
[23]. Manouchehrian, A., M.F. Marji, and M. Mohebbi. (2012). Comparison of indirect boundary element and finite element methods. Frontiers of Structural and Civil Engineering, 6(4): p. 385-392.
[24]. Lak, M., M.F. Marji, A.Y. Bafghi, and A. Abdollahipour. (2019). A coupled finite difference-boundary element method for modeling the propagation of explosion-induced radial cracks around a wellbore. Journal of Natural Gas Science and Engineering, 64: p. 41-51.
[25]. Abdollahi, M.S., M. Najafi, A.Y. Bafghi, and M.F. Marji. (2019). A 3D numerical model to determine suitable reinforcement strategies for passing TBM through a fault zone, a case study: Safaroud water transmission tunnel, Iran. Tunnelling and Underground Space Technology, 88: p. 186-199.
[26]. Ali, W., H. Rehman, R. Abdullah, Q. Xie, and Y. Ban. (2022). TOPOGRAPHY INDUCED STRESS AND ITS INFLUENCE ON TUNNEL EXCAVATION IN HARD ROCKS–A NUMERICAL APPROACH. GEOMATE Journal, 22(94): p. 93-101.
[27]. Nikadat, N. and M.F. Marji. (2016). Analysis of stress distribution around tunnels by hybridized FSM and DDM considering the influences of joints parameters. Geomechanics & engineering, 11(2): p. 269-288.
[28]. Nikadat, N., M. Fatehi, and A. Abdollahipour. (2015). Numerical modelling of stress analysis around rectangular tunnels with large discontinuities (fault) by a hybridized indirect BEM. Journal of Central South University, 22(11): p. 4291-4299.
[29]. Lee, J.-K., J. Kim, H. Rehman, and H.-K. Yoo, Evaluation of rock load based on stress transfer effect due to tunnel excavation. 2017.
[30]. Rehman, H., A.M. Naji, W. Ali, M. Junaid, R.A. Abdullah, and H.-k. Yoo. (2020). Numerical evaluation of new Austrian tunneling method excavation sequences: A case study. International Journal of Mining Science and Technology.
[31]. Hoek, E., C. Carranza-Torres, and B. Corkum. (2002). Hoek-Brown failure criterion-2002 edition. Proceedings of NARMS-Tac, 1: p. 267-273.
[32]. Bunji_Consultants, Main Report, Bunji Hydropower project. 2012.
[33]. Vestad, M. (2014). Analysis of the Deformation Behavior at the Underground Caverns of Neelum Jhelum HPP. Pakistan, Department of Geology and Mineral Resources Engineering, Norvegian University of Science and Technology.
[34]. DiPietro, J.A. and K.R. Pogue. (2004). Tectonostratigraphic subdivisions of the Himalaya: A view from the west. Tectonics, 23(5).
[35]. Bieniawski, Z. (1973). Engineering classification of jointed rock masses. Civil Engineer in South Africa, 15 (12): p. 333-343.
[36]. Rehman, H., A. Naji, J.-j. Kim, and H.-K. Yoo. (2018). Empirical Evaluation of Rock Mass Rating and Tunneling Quality Index System for Tunnel Support Design. Applied Sciences, 8(5): p. 782.
[37]. Kirsten, H., Case histories of groundmass characterization for excavatability, in Rock classification systems for engineering purposes. 1988, ASTM International.
[38]. Peck, W. (2000). Determining the stress reduction factor in highly stressed jointed rock. Aust Geomech, 35(2).
[39]. BIENIAWSKI, R.Z., D. AGUADO, B. CELADA, and A. RODRIQUEZ. (2011). Forecasting tunnelling behaviour. T & T international, (AOU): p. 39-42.
[40]. NGI. The Q-system, Rock mass classification and support design. 2015  09 04 2018]; Available from: https://www.ngi.no/eng/Publications-and-library/Books/Q-system.
[41]. Lowson, A. and Z. Bieniawski. (Year of conference). Critical assessment of RMR based tunnel design practices: a practical engineer’s approach. in Proceedings of the SME, Rapid Excavation and Tunnelling Conference, Washington, DC.
[42]. Carranza-Torres, C. and M. Diederichs. (2009). Mechanical analysis of circular liners with particular reference to composite supports. For example, liners consisting of shotcrete and steel sets. Tunnelling and Underground Space Technology, 24(5): p. 506-532.
[43]. Lee, J.K., H. Yoo, H. Ban, and W.-J. Park. (2020). Estimation of rock load of multi-arch tunnel with cracks using stress variable method. Applied Sciences, 10(9): p. 3285.
[44]. Yang, J., S. Wang, Y. Wang, and C. Li. (2015). Analysis of arching mechanism and evolution characteristics of tunnel pressure arch. Jordan Journal of Civil Engineering, 9(1).
[45]. Wang, S.-r., C.-l. Li, Y.-g. Wang, and Z.-s. Zou. (2016). Evolution characteristics analysis of pressure-arch in a double-arch tunnel/Analiza razvoja znacajki tlacnog svoda u tunelu s dvostrukim svodom. Tehnicki Vjesnik-Technical Gazette, 23(1): p. 181-190.