Comprehensive Evaluation and Practical Stabilization of Roadside Rock-Cut Slopes along the Narayangadh–Mugling Highway Section
DOI:
https://doi.org/10.64862/ajeg.2025.201.04Keywords:
Slope stability analysis, Rock anchors, Optimum rock-cut slope angle, Kinematic analysis, RMRbasic, SMRAbstract
The Narayangadh–Mugling Highway corridor in Nepal is highly vulnerable to recurrent rock-cut slope failures—including rockslides, rockfalls, toppling, and debris flows—that pose significant risks to life, infrastructure, and transportation. Two representative high-risk slopes were investigated through geological mapping, discontinuity surveys, and slope geometry measurements. Laboratory testing determined rock strength parameters and discontinuity shear strength. Rock mass quality was evaluated using RMRbasic and Slope Mass Rating (SMR) systems. Kinematic analysis identified potential planar, wedge, and toppling failures, while numerical modeling with SLIDE 5.0 computed factors of safety (FoS) under existing and remedial conditions. Both slopes were found to be critically unstable under current conditions. Installation of rock anchors at −150° significantly improved stability, while slope re-profiling to 60° (1H:1.73V) further enhanced performance. The combined approach of re-profiling with anchoring was identified as the most economical solution. The study provides practical insights for designing targeted slope stabilization measures, offering guidance for reducing geohazard risks along this critical transportation corridor.
References
Ahmad, R., and Joshi, M. N. (2010). Assessment of landslide susceptibility on land degradation processes in Chamoli and surrounding areas using RS and GIS technique. International Geoinformatics Research and Development Journal, 1(3).
Aleotti, P., and Chowdhury, R. (1999). Landslide hazard assessment: Summary review and new perspectives. Bulletin of Engineering Geology and the Environment, 58(1), 21–44. https://doi.org/10.1007/s100640050066
Baharvand, M., and Hosseinitoudeshki, V. (2015). The effect of installation angle of rock bolts on the stability of rock slopes. Journal of Novel Applied Sciences, 4(1), 67–71.
Bieniawski, Z. T. (1973). Engineering classification of jointed rock masses. Civil Engineering (South Africa), 15, 335–344.
Bieniawski, Z. T. (1976). Rock mass classifications in engineering. In Proceedings of the Symposium on Exploration Rock Engineering (pp. 97–106). Johannesburg.
Bieniawski, Z. T. (1989). Engineering rock mass classification. Wiley.
Brunsden, D., Jones, D. K. C., Martin, R. P., and Doornkamp, J. C. (1981). The geomorphological character of part of the Low Himalaya of eastern Nepal. Zeitschrift für Geomorphologie Supplementband, 40, 25–72.
Duncan, J. M., Wright, S. G., and Brandon, T. L. (2005). Soil strength and slope stability (2nd ed.). John Wiley and Sons.
Gerrard, J. (1994). The landslide hazard in the Himalayas: Geological control and human action. Geomorphology, 10(3), 221–230. https://doi.org/10.1016/0169-555X(94)90041-8
Goodman, R. E. (1995). Block theory and its application. Géotechnique, 45(3), 383–423. https://doi.org/10.1680/geot.1995.45.3.383
Goodman, R. E. (2000). Introduction to rock mechanics. John Wiley and Sons.
Haswanto, W. A., and Abd-Ghani, R. (2008). Kinematic and block theory applications to rock slope stability analysis at Fraser’s
Hill, Pahang, Malaysia. Electronic Journal of Geotechnical Engineering, 13(D).
Hoek, E., and Bray, J. W. (1981). Rock slope engineering (3rd ed.). Institute of Mining and Metallurgy.
Kainthola, A., Singh, P. K., and Singh, T. N. (2015). Stability investigation of road-cut slope in basaltic rock mass, Mahabaleshwar, India. Geoscience Frontiers, 6(6), 837–845. https://doi.org/10.1016/j.gsf.2014.06.006
Khanal, S., and Dahal, R.K. (2024). Influence of Precipitation Variability on Pore Water Pressure and Surface Layer Failures in Naturally Undulating Slopes at Nau Kilo, Narayanghat–Mugling Road, Central Nepal. Asian Journal of Engineering Geology, 1(1 and 2), 39-48. https://doi.org/10.64862/ajeg.112.05
Kliche, A. C. (1999). Rock slope stability. Society for Mining, Metallurgy, and Exploration.
OnlineKhabar (2017). Two killed, Two missing as landslide buries police van in Chitwan. Available at: https://english.onlinekhabar.com/2-killed-2-missing-as-landslide-buries-police-van-in-chitwan.html
Owen, L. A. (1991). Mass movement deposits in the Karakoram Mountains: Their sedimentary characteristics, recognition, and role in landform evolution. Geomorphology, 35(4), 401–424. https://doi.org/10.1016/0169-555X(91)90007-E
Paudyal, K. (2014). Geological and petrological evolution of Mugling–Damauli area of central Nepal, Lesser Himalaya (Doctoral dissertation). Tribhuvan University, Nepal.
Regmi, A. D., Yoshida, K., Dhital, M. R., and Devkota, K. (2013a). Effect of rock weathering, clay mineralogy, and geological structures on the formation of a large landslide: A case study from Dumre Besei, Lesser Himalaya, Nepal. Landslides, 10(4), 483–494. https://doi.org/10.1007/s10346-011-0311-7
Regmi, A. D., Devkota, K. C., Yoshida, K., Pradhan, B., Pourghasemi, H. R., Kumamoto, T., and Akgün, K. (2013b). Application and comparison of frequency ratio, statistical index, and weights-of-evidence models in landslide susceptibility mapping in central Nepal Himalaya. Arabian Journal of Geosciences, 6(7), 2727–2743. https://doi.org/10.1007/s12517-012-0807-z
Rocscience. (2006). Slide 5.0: 2D limit equilibrium slope stability analysis [Computer software]. Rocscience Inc.
Romana, M. (1985). New adjustment ratings for application of Bieniawski classification to slopes. In International Symposium on the Role of Rock Mechanics (ISRM) (pp. 49–53). Zacatecas.
Romana, M. (1995). The geomechanics classification SMR for slope correction. In Proceedings of the 8th International ISRM Congress (pp. 1085–1092).
Sharma, R. K., Mehta, B. S., and Jamwal, C. S. (2013). Cut slope stability evaluation of NH-21 along the Natayan–Gambhrola section, Bilaspur District, Himachal Pradesh, India. Natural Hazards, 66(1), 249–270. https://doi.org/10.1007/s11069-012-0469-x
Shroder, J. F., and Bishop, M. P. (1998). Mass movement in the Himalaya: New insights and research directions. Geomorphology, 26(1–3), 13–35. https://doi.org/10.1016/S0169-555X(98)00052-7
Singh, P. K., Kainthola, A., and Singh, T. N. (2013). Rock mass assessment along the right bank of the River Sutlej, Luhri, Himachal Pradesh, India. Geomatics, Natural Hazards and Risk, 5(3), 205–222. https://doi.org/10.1080/19475705.2013.834486
Umrao, R. K., Singh, R., Ahmad, M., and Singh, T. N. (2011). Stability analysis of cut slopes using continuous slope mass rating and kinematic analysis in Rudraprayag District, Uttarakhand. Geomaterials, 1(2), 79–87. https://doi.org/10.4236/gm.2011.12012
World Bank (2025). Protecting slopes to build resilient roads in Nepal. Available at: https://www.worldbank.org/en/news/feature/2025/02/10/protecting-slopes-to-build-resilient-roads-in-nepal
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