STABILITY ANALYSIS OF ROCK BLOCKS WITH ENTIRE SPHERE STEREOGRAPHIC PROJECTION BASED ON THE BLOCK THEORY: A CASE STUDY FOR A TUNNEL ENTRANCE PROJECT
DOI:
https://doi.org/10.29121/granthaalayah.v10.i8.2022.4735Keywords:
Entire Sphere Stereographic Projection, Block Theory, Rock Masses, Rock Failure, Tunnel Entrance ProjectAbstract [English]
This paper presents a static equilibrium kinematic analysis of rock performed in the tunnel entrance project using entire sphere stereographic projection under block theory. The objective of this study is to improve the predictive analysis of rock masses in terms of stability in rock masses area. Different key blocks with failure modes are determined. The conventional upper hemisphere stereographic projection is also employed for comparative analysis. Based on the findings, it was concluded that the planar failure is not probable in the case of the kinematic and block theory method in the tunnel entrance area. However, the wedge failure is more probable in both cases of analysis and the number of possible slide blocks in the case of kinematic analysis was found to be less than in the case of block theory; In these conditions, the support system should be provided for the reasons of safety. The comparative analysis shows that the results of block theory analysis are close to reality and provide more precision on the stable and unstable block than the results of kinematic analysis; Moreover, the block theory method using the entire sphere stereographic projection provides more precision on the sliding angle than the use of one sphere stereographic projection. Based on this study, the tunnel entrance is more stable for the dip slope face equal to 45 and not probable for slope face 60˚ and 85˚; but these results were limited in the case of stability analysis under gravitational loading.
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Azarafza, M., Asghari-Kaljahi, E., and Akgün, H. (2017). Assessment of Discontinuous Rock Slope Stability with Block Theory And Numerical Modeling: A Case Study for The South Pars Gas Complex, Assalouyeh, Iran. Environ Earth Sci. 76, 397. https://doi.org/10.1007/s12665-017-6711-9 DOI: https://doi.org/10.1007/s12665-017-6711-9
Fu, G.Y, Ma, G.W.(2014). Extended Key Block Analysis For Support Design of Blocky Rock Mass. Tunneling and Underground Space Technology, 41, 1-13. http://dx.doi.org/10.1016/j.tust.2013.11.003 DOI: https://doi.org/10.1016/j.tust.2013.11.003
Gischig V. S. (2011). Kinematic and Failure Mechanism of Randa Rock Slope Instability (Switzerland). Ph.D Thesis, ETH ZURICH, 217.
Goodman, R. E., Shi, G. (1985). Block Theory and Its Application to Rock Engineering. Prentice-Hall Inc., New Jersey, USA.
Hoek, E. Bray, J. W. (1981). “Rock Slope Engineering, 3rd Ed. Institute of Mining and Metallurgy,” London, 358. DOI: https://doi.org/10.1201/9781482267099
Inc. Rocscience (2014), “Dip V.6.0 – Graphical And Statistical Analysis of Orientation Data. Toronto,” Canada.
Kulatilake, P. H. S. W, Wang, L., Tang, H., and Liang, Y.(2011). Evaluation of Rock Slope Stability for Yujian River Dam Site By Kinematic and Block Theory Analyses. Computers and Geotechnics, 38, 846–860. https://doi.org/10.1016/j.compgeo.2011.05.004 DOI: https://doi.org/10.1016/j.compgeo.2011.05.004
Li, J., Xue, J., Xiao, J., and Wang, Y.(2012). Block Theory on the Complex Combinations of Free Planes. Computers and Geotechnics, 40, 127–134. https://doi.org/10.1016/j.compgeo.2011.10.006 DOI: https://doi.org/10.1016/j.compgeo.2011.10.006
Li, J., Yuan, G., Zhang, Y., and Zhao, Y. (2015). “Study on a General Cutting Algorithm of Complex Blocks”, Geotechnical and Geological Engineering, 33, 1193-1203. DOI: https://doi.org/10.1007/s10706-015-9895-3
Mboussa D. J. W., Sun S. (2022). Analysis of Rock Mass Behavior with Empirical and Numerical Method for The Construction of Diversion Tunnel, Laos : IOP Conf. Series: Material Sciences and Engineering 1212, 012028. DOI: https://doi.org/10.1088/1757-899X/1212/1/012028
Mboussa,D. J. W., Sun, S. Zhang, Y., and Elenga H. I.(2019). “Rock Slope Stability Analysis With A Kinematic Method for the Nam Phoun Dam Site, Laos”, IOP Conference Series: Earth and Environmental Science, 362, 012137. DOI: https://doi.org/10.1088/1755-1315/362/1/012137
Noroozi, M., Jalali, S. E., and Yarahmadi-Bafghi, A.R. (2011). 3D Key-Group Method Forslope Stability Analysis. Int. J. Numer. Anal. Meth. Geomech., 36(16), 1780-1792. http://dx.doi.org/10.1002/nag.1074 DOI: https://doi.org/10.1002/nag.1074
Stead, D., Wolter, A.(2015). A Critical Review of Rock Slope Failure Mechanisms: The Importance of Structural Geology. Journal of Structural Geology 74, 1- 23. https://doi.org/10.1016/j.jsg.2015.02.002 DOI: https://doi.org/10.1016/j.jsg.2015.02.002
Thompson, A. G., (2002). Stability Assessment And Reinforcement of Block Assemblies Near Underground Excavations. Mining and Tunneling Innovation and Opportunity In: Hammah, Bawden, Curran, Telesnicki (Eds.), Proceedings of 5th North American Rock Mechanics Symposium and the 17th Tunneling Association of Canada Conference: NARMS-TAC V2, 1439–1446, University of Toronto Press: Toronto.
Thompson, A.G., Windsor, C.R. (2007). Block Formation Around Excavations Using Deterministic and Probabilistic Methods. In : 11th ISRM Congress on Rock Mechanics, V2, 183–186, Lisbon, July, Taylor and Francis : London.
Um, J., Kulatilak, P. H. S. W. (2001). Kinematic and Block Theory Analysis for Shiplock Slopes of the Three Gorges Dam Site in China. Geotechnical and Geological Engineering Journal 19, 21 – 42. DOI: https://doi.org/10.1023/A:1012284727685
Warburton, P.M. (1981). Vector Stability Analysis of an Arbitrary Polyhedral Rock Block with Any Number of Free Faces, Int J Rock Mech Min Sci., 18(5), 415–427. https://doi.org/10.1016/0148-9062(81)90005-X DOI: https://doi.org/10.1016/0148-9062(81)90005-X
Wibowo, J. L., (1997). Consideration of Secondary Block in Key-Block Analysis. Int. J. Rock Mech. Min. Sci., 34 (3–4), 333. https://doi.org/10.1016/S1365-1609(97)00131-7 DOI: https://doi.org/10.1016/S1365-1609(97)00131-7
Windsor, C.R.(1997). Rock Reinforcement Systems. Int. J. Rock Mech. Min. Sci., 34 (6),919–951. https://doi.org/10.1016/S1365-1609(97)80004-4 DOI: https://doi.org/10.1016/S1365-1609(97)80004-4
Windsor, C.R., Thompson, A.G., (1992). Reinforcement Design for Jointed Rock Mass. In : Tillerson, J.R., Wawersik, W.R., Balkema, Rotterdam (Eds.), Proc., 33rd US Symp. Rock Mech. Sante Fe. Rock Mechanics, 521–530.
Yarahmadi-Bafghi, A.R. and Verdel, T. (2003). The Key-Group Method. Int. J. Num. Anal. Meth. Geomech 27,495–511. https://doi.org/10.1002/nag.283 DOI: https://doi.org/10.1002/nag.283
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Copyright (c) 2022 Djohn Josia Weaver Mboussa, Shulin Sun, Paul Nkombe Joseph, Yan Zhang
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