Rock Mass Classification Using RMR and GSI for Slope Stability at PT Bukit Asam, Tanjung Enim

Dona Sabila, Harnani Harnani, Muhammad Hafits Qistan, Muhammad Sidiq

Abstract


Evaluating slope stability in tropical open-pit mining environments remains a technical challenge due to the complex geological formations and the influence of dynamic climatic conditions, particularly intense rainfall and high humidity. This study aims to assess the effectiveness of integrating the Rock Mass Rating (RMR) system and the Geological Strength Index (GSI) for classifying rock mass quality and predicting slope stability in such settings. Field data were collected from interbedded claystone and sandstone formations through systematic mapping of RMR parameters, including Rock Quality Designation (RQD), spacing and condition of discontinuities, groundwater presence, and uniaxial compressive strength. Complementary evaluations using GSI focused on block structure, joint surface conditions, and weathering characteristics. The RMR analysis classified the rock mass as Class III (Fair Rock), indicating moderate stability. However, the system’s static framework and limited responsiveness to rapid hydrogeological changes posed constraints in capturing the actual slope behavior. In contrast, GSI, with values ranging between 40 and 50, offered enhanced interpretive depth by incorporating qualitative assessments of lithological heterogeneity and structural anisotropy. The adaptability of GSI proved critical in environments where visual and textural indicators of degradation fluctuate spatially and temporally. The combined application of RMR and GSI enabled a more accurate, context-sensitive geotechnical evaluation, bridging the gap between empirical rigidity and field-based complexity. This integrated methodology supports more reliable engineering decisions and enhances the predictive capacity for slope failures in tropical geological settings, emphasizing the necessity for multidimensional classification tools in geotechnical practice.

Keywords


RMR; GSI; slope stability; tropical geology; rock mass; geotechnical analysis.

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References


Barton, N., Wang, C., & Yong, R. (2023). Advances in joint roughness coefficient (JRC) and its engineering applications. Journal of Rock Mechanics and Geotechnical Engineering, 15(12), 3352–3379. https://doi.org/10.1016/J.JRMGE.2023.02.002

Bieniawski, Z.T. (1989). Engineering Rock Mass Classification: A Complete Manual for Engineers and Geologists in Mining, Civil, and Petroleum Engineering. Canada: John Wiley and Sons.

Chen, T., Shu, J., Han, L., Tovele, G. S. V., & Li, B. (2023). Landslide mechanism and stability of an open-pit slope: The Manglai open-pit coal mine. Frontiers in Earth Science, 10, 1038499. https://doi.org/10.3389/FEART.2022.1038499

Deliveris, A. V., Theocharis, A. I., Koukouzas, N. C., & Zevgolis, I. E. (2022). Numerical Slope Stability Analysis of Deep Excavations Under Rainfall Infiltration. Geotechnical and Geological Engineering, 40(8), 4023–4039. https://doi.org/10.1007/S10706-022-02135-4

Dong, S., Zhang, H., Peng, Y., Lu, Z., & Hou, W. (2022). Method of calculating shear strength of rock mass joint surface considering cyclic shear degradation. Scientific Reports, 12(1), 1–14. https://doi.org/10.1038/S41598-022-13505-6

Hasan, M., Shang, Y., Yi, X., Shao, P., & He, M. (2023). Determination of rock mass integrity coefficient using a non-invasive geophysical approach. Journal of Rock Mechanics and Geotechnical Engineering, 15(6), 1426–1440. https://doi.org/10.1016/J.JRMGE.2022.07.008

Muarif, I. F., Maryati, S., Hutagalung, R., Kunci, K., Lereng, K., & Massa Batuan, K. (2022). Analisis Kelas Massa Batuan Terhadap kestabilan Lereng Bendungan Lolak Menggunakan Metode Rock Mass Rating. Journal of Applied Geoscience and Engineering, 1(2), 61–75. https://doi.org/10.34312/JAGE.V1I1.15507

Johari, M. A. F., Mazlan, S. A., Ubaidillah, U., Nordin, N. A., Ahmad Khairi, M. H., Abdul Aziz, S. A., Sedlacik, M., & Nikmat Leong, S. A. (2022). Natural Weathering Effects on the Mechanical, Rheological, and Morphological Properties of Magnetorheological Elastomer (MRE) in Tropical Climate. International Journal of Molecular Sciences 2022, Vol. 23, Page 9929, 23(17), 9929. https://doi.org/10.3390/IJMS23179929

Marinos, V., Marinos, P. and Hoek, E. (2005). Geological Strength Index: Applications and Limitations. Bulletin of Engineering and Environmental Geology, 64, 55-65. https://doi.org/10.1007/s10064-004-0270-5

Marotti, J. C., Gomes, G. J. C., Velloso, R. Q., Vargas Júnior, E. A., Nunes, R. S., & Fernandes, N. F. (2023). Exploring extreme rainfall-triggered landslides using 3D unsaturated flow, antecedent moisture and spatially distributed soil depth. CATENA, 229, 107241. https://doi.org/10.1016/J.CATENA.2023.107241

Narimani, S., Davarpanah, S. M., Bar, N., Török, Á., & Vásárhelyi, B. (2023). Geological Strength Index Relationships with the Q-System and Q-Slope. Sustainability 2023, Vol. 15, Page 11233, 15(14), 11233. https://doi.org/10.3390/SU151411233

Shao, J., Zhang, W., Wu, X., Lei, Y., & Wu, X. (2022). Rock Damage Model Coupled Stress-Seepage and Its Application in Water Inrush from Faults in Coal Mines. ACS Omega, 7(16), 13604–13614. https://doi.org/10.1021/acsomega.1c07087

Shu, S., Ge, B., Wu, Y., & Zhang, F. (2023). Probabilistic Assessment on 3D Stability and Failure Mechanism of Undrained Slopes Based on the Kinematic Approach of Limit Analysis. International Journal of Geomechanics, 23(1), 06022037. https://doi.org/10.1061/(ASCE)GM.1943-5622.0002635

Singh, J., Pradhan, S. P., Vishal, V., & Singh, M. (2023). Characterization of a fractured rock mass using geological strength index: A discrete fracture network approach. Transportation Geotechnics, 40, 100984. https://doi.org/10.1016/J.TRGEO.2023.100984

Uno, D. A. N., Uno, I., Saputra, A., Arum, D. A., Mumin, R. P., & Alfaed, M. R. F. (2025). Analysis Slope Stability Using RMR and SMR Method in Nupaomba Area Tanantovea Donggala. Jambura Geoscience Review, 7(1), 60–67. https://doi.org/10.37905/JGEOSREV.V7I1.30388

Yang, Y., Jiang, Q., Liu, J., Zheng, H., Xu, D., & Xiong, J. (2023). Equivalent Constitutive Model for Jointed Rock Masses and Its Application in Large Underground Caverns. International Journal of Geomechanics, 23(1), 04022259. https://doi.org/10.1061/(ASCE)GM.1943-5622.0002633

Zhang, L., Chen, Z., Bao, M., Nian, G., Zhou, Z., & Zhu, T. (2022). Stability analysis and movement process determination of rock masses under open-pit to underground mining conditions. Geomechanics and Geophysics for Geo-Energy and Geo-Resources, 8(5), 1–19. https://doi.org/10.1007/S40948-022-00459-2

Zhou, J., Lou, J., Wei, J., Dai, F., Chen, J., & Zhang, M. (2023). A 3D microseismic data-driven damage model for jointed rock mass under hydro-mechanical coupling conditions and its application. Journal of Rock Mechanics and Geotechnical Engineering, 15(4), 911–925. https://doi.org/10.1016/J.JRMGE.2022.10.002




DOI: https://doi.org/10.37905/jgeosrev.v7i2.32492

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