ROCK MASS RATING AND GEOLOGICAL STRENGTH INDEX OF ROCK MASSES OF INDONESIA COAL MINING AREAS
Abstract
Abstract
Rock slope stability is important for the safety of personnel and equipment in open pit mines. Slope instability and failure occurs due to many factors such as adverse slope geometries, geological discontinuities, weak or weathered slope materials. External loads such as high rainfall and seismicity can play an important role in slope failure. For this reason, it is necessary to classify the rock mass accurately against a rock mass as the basis for determining the technical policy of the rock mass. Rock slopes in open-pit coal mining areas, especially in Indonesia, are characterized by applying various rock mass classification systems, such as the Rock Mass Rating (RMR) and Geological Strength Index (GSI), because the study area consists of well exposed rock formations. In the RMR system, there are five main parameters namely. Uniaxial Compressive Strength (UCS) of rocks, Rock Quality Designation (RQD), discontinuity distances, discontinuity conditions, and groundwater conditions are considered. In this paper, several rock mass classification systems developed for the assessment of rock slope stability are evaluated against rock slope conditions in the tropics, namely the Indonesian region, especially in sedimentary rocks in coal-open mining areas. So that the corrected GSI equation is obtained which is used to characterize rock slopes based on the quantitative analysis of the rock mass structure and the surface conditions of the discontinuity.
Keywords : RMR, GSI, UCS, Rock, Quality, Designation
Stabilitas lereng batuan penting untuk diperhatikan bagi keselamatan personel dan peralatan di tambang terbuka. Ketidakstabilan dan kegagalan lereng terjadi karena banyak faktor seperti geometri lereng yang merugikan, diskontinuitas geologis, material lereng yang lemah atau lapuk akibat pengaruh cuaca. Beban eksternal seperti curah hujan yang tinggi dan kegempaan dapat memainkan peran penting dalam kegagalan lereng. Untuk itu diperlukan klasifikasi massa batuan secara tepat terhadap suatu massa batuan sebagai dasar penentuan kebijakan teknis terhadap massa batuan tersebut. Lereng batuan di daerah tambang terbuka batubara khususnya di Indonesia, dikarakterisasi dengan menerapkan berbagai sistem klasifikasi massa batuan, seperti Rock Mass Rating (RMR) dan Geological Strength Index (GSI), karena daerah penelitian terdiri dari formasi batuan yang terekspos dengan baik. Dalam sistem RMR, terdapat lima parameter utama yaitu. Uniaxial Compressive Strength (UCS) dari batuan, Rock Quality Designation (RQD), jarak diskontinuitas, kondisi diskontinuitas, dan kondisi air tanah dipertimbangkan. Dalam makalah ini, beberapa sistem klasifikasi massa batuan yang dikembangkan untuk penilaian stabilitas lereng batuan dievaluasi terhadap kondisi lereng batuan pada daerah tropis yaitu wilayah Indonesia, khususnya pada batuan sedimen di wilayah tambang terbuka batubara. Sehingga didapatkan persamaan GSI terkoreksi yang digunakan untuk mengkarakterisasi lereng batuan berdasarkan analisis kuantitatif struktur massa batuan dan kondisi permukaan dari diskontinuitas.
Kata Kunci : RMR, GSI, UCS, Rock, Quality, Designation
Keywords
Full Text:
PDFReferences
Barton, N. and Stephansson (1990): Rock Joint Review of Predictive Capabilities of JRC-JCS Model in Engineering Practice, Proc. Intrnl. Symp. On Rock Joint, Leon, Norway.
Barton, N.R. (1976): The shear strength of rock and rock joints, Intl. J. Rock Mech. Min. & Sci. Vol. 13: 255-279.
Bieniawski, Z.T. (1968): The Effect of Specimen Size on The Strength of Coal, International Journal on Rock Mechanics and Mining Sciences & Mecahnics Abstracts, V. 5 n. 4, 325-335.
Bieniawski, Z.T. (1973): Engineering Classification of Jointed Rock Masses, Trans. S. Afr. Inst. Civ. Eng. 15. pp. 335 – 344.
Bieniawski, Z.T. (1989): Engineering Rock Mass Classifications, John-Wiley, New York.
Brady, B.H.G. and Brown, E.T. (1985): Rock Mechanics for Underground Mining, George Allen and Unwin, London.
Dwinagara, B. (2006): Penentuan Kekuatan Jangka Panjang Massa Batuan Dengan Metode Tidak Langsung dari Hasil Pengukuran dan Pengujian Insitu, Disertasi, ITB, Bandung.
Edmond, J.M. and Paterson, M.S. (1972): Volume Changes during The Deformation of Rocks at High Pressures, Int. Journ. Rock Mech. Min. & Sci., Vol. 9, pp. 161-182.
Grasselli, G. (2001): Shear Strength of Rock Joints Based on Quantified Surface Description, Geophysical Technology Department, Sandia National Laboratories, New Mexico, USA.
Griffith, A.A. (1925): The Theory of Rupture, Proceeding of 1st Institutional Congress of Applied Mechanics, Delft. Biezeno and Burgers ed. Waltman, pp. 55 – 63.
Haines, A. and Terburgger, P.J. (1991): Preliminary Estimation of Rock Slope Stability Using Rock Mass Classification System, Proc. 7th Int. Society Rock Mechanics (Herausgeber ed.) Aachen. Vol 2 pp. 887 – 892.
Herget, G. (1988): Stresses in Rock, A.A. Balkema Publ: 179p.
Herryal, Z.A., Shimada, H., Ichinose, M., Matsui, K., Zulfahmi, M.F., (1999): Study on The Application of Rock Bolting Technology in Ombilin and Ikeshima Coal Mine, Ed. Matsui K., and Shimada, H. Japan-Korea Joint Symposium on Rock Engineering, Fukuoka, Japan.
Herryal, Z.A. (2000): Study on the progression and control of rock strength deterioration due to water, Ph.D. Dissertation, Department of Earth Resources Engineering, Kyushu University.
Hoek, E. (1994): Strength of Rock and Rock Masses, ISRM News Journal, 2 No. 2, 4-16.
ISRM (1981): Rock Characterization Testing and Monitoring ISRM Suggested Method. E.T. Brown (Ed). Pergamon Press. 5 – 30.
Janbu, N. (1954): Stability Analysis of Slopes with Dimensionless Parameter, D.Sc. thesis, Harvard Univerity, Cambridge, MA.
Johnstone, I. W. (1991): Discussion on The Development and Applications of A Synthetic Material to Simulate Soft Sedimentary Rock, Geotchnique, Vol. 41. No. 1, pp. 165 – 167.
Kramadibrata, S. (1996): The Influence of Rock Mass and Intact Rock Properties on The Design of Surface Mines with Particular Reference to The Excavatability of Rock, Ph. D. Thesis, Curtin University of Technology.
Kramadibrata, S., Saptono, S., Sulistianto, B. and Wattimena, R.K. (2011a): Penentuan Kriteria dan Prosedur Analisis Stabilitas Lereng Batuan Lunak di Tambang Terbuka Batubara, DIPA – Dikti, Pameran Poster, ITB, Bandung.
Kramadibrata, S., Saptono, S., Sulistianto, B. and Wattimena, R.K. (2011b): Pengujian Geser Langsung Skala Besar di Lapangan, Riset – KK ITB, Pameran Poster, ITB, Bandung.
Li, A.J., Merifield, R.S. and Lyamin, A.V. (2008): Stability Charts for Rock Slopes Based on The Hoek-Brown Failure Criterion, International Journal of Rock Mechanics & Mining Sciences 45 (2008) 689 – 700.
Lin, Y. (1998): An Introduction of The Chinese Standard for Engineering Classification of Rock Mass, In Advances in Rock Mechanics (Lin ed.), World Scientific Publishing Co., Singapore, pp. 317-327.
Londe, P. (1973): The Role of Rock Mechanics in The Reconnaissance of Rock Foundations, Qly J. Engng Geol., Vol 6/1.
Michalowski, R.L. (2002): Stability Charts for Uniform Slopes, Journal of Geotchnical and Geoenviromental Engineering, Vol. 128. No.4.
Muratha, J. and Cunha, P.A. (1990): About LNEC Experience on Scale Effects in The Mechanical Behaviour of Joints, Proc. The 1st Intl. Workshop on scale effects in Rock masses, Edited by Cunha, P.A. Luen, Norway 131-148.
Nakamura, S.T. (1949): On Visco-Elastic Medium. Sci. Rep. Tokyo Univ., 5th Series Geophysics, Vol. 1. No. 2, pp. 91-95.
Newland, P.L. and Alley, B.H. (1957): Volume Changes in Drained Triaxial Tests on Granular Material. , Geotechnique, Vol. 7, pp. 17 – 34.
Novello, E.A. (1988): Geomechanics and The Critical State, Ph.D. Thesis, Monash University, Melbourne.
Pankhrust, R.C. (1964): Dimensional Analysis and Scale Factor, Chapman & Hall Ltd. London.
Patton, F.D. (1966): Multiple Modes of Shear failure in Rock, In. Proc. 1st International Congress on Rock Mechanics (Lisbon), Vol. 1, pp. 509 – 513.
Pratt, H.R., Black, A.D. and Brace, W,F. (1972): Friction and Deformation of Jointed Quartz Diorite, Proc. 3rd Cong. of Int. Soc. Rock Mech., Denver Colorado, Vol. II. A: 306-310.
Rai, M.A., Kramadibrata, S. dan Wattimena, R.K. (2011): Mekanika Batuan, Penerbit ITB.
Saptono, S. (2011): Penentuan kekuatan geser jangka panjang batupasir dengan pendekatan perilaku rayapan geser visko-elastik. Seminar Kebumian Nasional, FTM – UPN ”Veteran” Yogyakarta. Yogyakarta.
Saptono, S., Kramadibrata, S. and Sulistianto, B. (2010): The Use of Rock Mass Characteristic for Assessing Slope Stability, The 5th AUTOLE International Postgraduate Students Conference on Engineering, ITB, Bandung, Indonesia.
Saptono, S., Kramadibrata, S., Sulistianto, B., Wattimena, K.R., Nugroho, P., Iskandar, E. and Bahri, S., (2008a): Low Wall Slope Monitoring By Robotic Theodolite System Likely to Contribute to Increased Production of Coal in PT. Adaro Indonesia, Proceeding 1st Southern Hemisphere International Rock Mechanics Symposium, Vol. 1, Potvin et al. eds. Perth. Australia.
Singh, M.M. (1981): Strength of rock. Physical properties of rock and materials, New York.
Singh, R.N., Hassani, F.P. and Elkington, P.A.S. (1983): The Application of Strength and Deformation Index Testing to The Stabality Assessment of Coal Measures Excavation,. Proceedings 24th US Symposium on Rock Mechanics, Texas A&M University, 599-609.
Sulistianto, B., Kramadibrata, S., Saptono, S., Wattimena, R.K. and Nugroho, P. (2009): Deformation Monitoring at Low-wall slope of coal open pit in PT. Adaro Indonesia, Earth resource science and technology, 2nd International Symposium of Novel Carbon Resources Science, March, ITB.
Taylor, D.W. (1937): Stability or Earth Slopes, Journal of the Boston Society of Civil Engineer, 24: 197 – 256.
Terzaghi, K. (1946): Rock Defects and Loads on Tunnel Support, Rock Tunneling with Steel Support, Commercial Shearing Co., Youngstown, OH., pp. 15 – 99.
Terzaghi, R.D. (1965): Sources of Error in Joint Surveys, Geotechnique, Vol. XV. Pp. 287 – 304.
Unal, E. (1996): Modified Rock Mass Classification: M-RMR System, Milestone in Rock Engineering, Balkema. Pp. 203 – 223.
Vutukuri, V.S. Lama, R.D. and Saluja, S.S. (1974): Handbook on mechanical properties of rocks, Vol., Trans Tech. Publ.
Wattimena, R.K., Kramadibrata,, S., Sulistianto, B. dan Saptono, S. (2009): Pengujian Geser Langsung Skala Besar, Riset – KK ITB, ITB, Bandung.
Yang, S.Q. and Cheng, L. (2011): Non-Stationary and Nonlinier Visco-Elastic Shear Creep Model for Shale, International Journal Rock Mechanics & Mining Sciences, Elsevier.
Yoshinaka, R., Yoshida, J., Arai, H. and Arisaka, S. (1993): Scale Effects on Shear Strength The Deformability of Rock Joint, The 2nd Intl. Workshop on scale effects in Rock masses, Edited by Cunha, P.A. Lisbon, Portugal, 143-149.
Refbacks
- There are currently no refbacks.