Geomechanics and Engineering

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Comparative study of stability analysis methods for slopes with weak soil layers

  • Lei Huang (College of Architecture and Civil Engineering, Sanming University) ;
  • Leilei Liu (Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring, Ministry of Education, School of Geosciences and Info-Physics, Central South University)
  • Received : 2025.03.25
  • Accepted : 2026.01.27
  • Published : 2026.02.10
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Abstract

This paper revisits a classical topic in the geotechnical profession, i.e., how to select an appropriate method for slope stability analysis. This study focuses on slopes with weak soil layers, and the methods investigated are the typical approaches based on the frameworks of limit equilibrium method (LEM), finite element method (FEM) and limit analysis (LA). This study includes the LEMs, finite element stress method (FESM), strength reduction method (SRM) and discontinuity layout optimization (DLO). It is found that when dealing with slopes with weak soil layers using LEM, there are higher requirements for the factor of safety (FS) iteration algorithm. The difficulty in convergence of FS during iterative solution may occur due to the assumption regarding the inter-slice force, which may cause overestimated FS with relative error exceeding 45% for a slope with a weak foundation layer. Meanwhile, the inherent transition of failure mechanisms of slopes with weak layers increases the difficulty in determining the critical slip surface by LEMs. The non-convergence issue is avoided in FESM, but its FS results are sensitive to the model domain and element size for a slope with a thin soft band (FS results ranging from 0.439 to 1.238 under different element sizes and model domains), exhibiting unsatisfactory performance under complex conditions. In general, DLO has better performance in analyzing the stability of slopes with weak soil layers, especially in capturing the failure mechanism.

Keywords

Acknowledgement

This study is supported by Fujian Provincial Natural Science Foundation of China (Grant No.: 2025J011055); and the start-up funding from Sanming University (Project No.: 24YG03). The financial support is greatly acknowledged. Furthermore, we would like to express our gratitude to Professor Yung-ming Cheng, who has retired from The Hong Kong Polytechnic University for the guidance, suggestions and support regarding this work.

References

  1. Griffiths, D.V., Lane, P.A. (1999). Slope stability analysis by finite elements. Géotechnique, 49(3), 387-403. https://doi.org/10.1680/geot.51.7.653.51390.
  2. Cheng, Y.M., Lansivaara, T., Wei, W.B. (2007). Two-dimensional slope stability analysis by limit equilibrium and strength reduction methods. Computers and Geotechnics, 34, 137-150. https://doi.org/10.1016/j.compgeo.2007.05.006.
  3. Alkasawneh, W., Malkawi, A.I.H., Nusairat, J.H., Albataineh, N. (2008). A comparative study of various commercially available programs in slope stability analysis. Computers and Geotechnics, 35(3), 428-435. https://doi.org/10.1016/j.compgeo.2007.06.009.
  4. Wei, W.B., Cheng, Y.M. (2010). Soil nailed slope by strength reduction and limit equilibrium methods. Computers and Geotechnics, 37(5), 602-618. https://doi.org/10.1016/j.compgeo.2010.03.008.
  5. Liu, S.Y., Shao, L.T., Li, H.J. (2015). Slope stability analysis using the limit equilibrium method and two finite element methods. Computers and Geotechnics, 63, 291-298. https://doi.org/10.1016/j.compgeo.2014.10.008.
  6. Lim, K., Li, A.J., Schmid, A., Lyamin, A.V. (2017). Slope-stability assessments using finite-element limit-analysis methods. International Journal of Geomechanics, 17(2), 06016017. https://doi.org/10.1061/(ASCE)GM.1943-5622.0000715.
  7. Chen, X., Zhang, L., Chen, L., Li, X., Liu, D. (2019). Slope stability analysis based on the coupled eulerian-lagrangian finite element method. Bulletin of Engineering Geology and the Environment, 78(6), 4451-4463. https://doi.org/10.1007/s10064-018-1413-4.
  8. Elkamhawy, E., Wang, H., Zhou, B., Yang, Z. (2018). Failure mechanism of a slope with a thin soft band triggered by intensive rainfall. Environmental Earth Sciences, 77(9), 340. https://doi.org/10.1007/s12665-018-7538-8.
  9. Xu, J.S., Li, Y.X., Yang, X.L. (2018). Stability charts and reinforcement with piles in 3D nonhomogeneous and anisotropic soil slope. Geomechanics and Engineering, 14(1), 71-81. https://doi.org/10.12989/gae.2018.14.1.071.
  10. Tran, A.T.P., Kim, A.R., Cho, G.C. (2019). Numerical modeling on the stability of slope with foundation during rainfall. Geomechanics and Engineering, 17(1), 109-118. https://doi.org/10.12989/gae.2019.17.1.109.
  11. Zhang, W., Wang, D. (2020). Stability analysis of cut slope with shear band propagation along a weak layer. Computers and Geotechnics, 125(1), 103676. https://doi.org/10.1016/j.compgeo.2020.103676.
  12. Zuo, J.Y., Wang, B.T., Li, W.W., Zhang, H.X. (2022). Upper-bound solution for the stability analysis of layered slopes. Journal of Engineering Mechanics, 148(3), 04022007. https://doi.org/10.1061/(ASCE)EM.1943-7889.0002087.
  13. Qin, C.B., Zhou, J.F. (2023). On the seismic stability of soil slopes containing dual weak layers: true failure load assessment by finite-element limit-analysis. Acta Geotechnica, 18, 3153-3175. https://doi.org/10.1007/s11440-022-01730-2.
  14. Janbu, N. (1957). Earth pressure and bearing capacity by generalized procedure of slices. Proceedings of the Fourth International Conference on Soil Mechanics, London, UK, August.
  15. Deng, D.P., Li, L., Zhao, L.H. (2019). Stability analysis of slopes under groundwater seepage and application of charts for optimization of drainage design. Geomechanics and Engineering, 17(2), 181-194. https://doi.org/10.12989/gae.2019.17.2.181.
  16. Deng, D.P., Lu, K., Wen, S.S., Li, L. (2020). The expanded LE Morgenstern-Price method for slope stability analysis based on a force-displacement coupled mode. Geomechanics and Engineering, 23(4), 313-325. https://doi.org/10.12989/gae.2020.23.4.313.
  17. Motlagh, A.T., Ghanbari, A., Maedeh, P.A., Wu, W. (2018). A new analytical approach to estimate the seismic tensile force of geosynthetic reinforcement respect to the uniform surcharge of slopes. Earthquakes and Structures, 15(6), 687-699. https://doi.org/10.12989/eas.2018.15.6.687.
  18. Azarafza, M., Akgün, H., Asghari-Kaljahi, E. (2017). Assessment of rock slope stability by slope mass rating (SMR): A case study for the gas flare site in Assalouyeh, South of Iran. Geomechanics and Engineering, 13(4), 571-584. https://doi.org/10.12989/gae.2017.13.4.571.
  19. Das, S.K., Mandal, K.K., Niyogi, A.G. (2022). A finite element based approach to observe hydrodynamic pressure in reservoir adjacent to concrete gravity dam. Ocean Systems Engineering, 12(4), 385-402. https://doi.org/10.12989/ose.2022.12.4.385.
  20. Yi, Z., Kang, J. (2025). Finite element-based spatial distribution model for slope stability during earthquakes. Earthquakes and Structures, 28(2), 149-159. https://doi.org/10.12989/eas.2025.28.2.149.
  21. Liu, S.Y., Su, Z.N., Li, M., Shao, L.T. (2020). Slope stability analysis using elastic finite element stress fields. Environmental Earth Sciences, 273, 105673. https://doi.org/10.1016/j.enggeo.2020.105673.
  22. Su, Z.N., Shao, L.T. (2021). A three-dimensional slope stability analysis method based on finite element method stress analysis, Environmental Earth Sciences, 280, 105910. https://doi.org/10.1016/j.enggeo.2020.105910.
  23. Nandi, S., Santhoshkumar, G., Ghosh, P. (2022). Assessment of seismic stability of finite slope in c-ϕ soils-a plasticity approach. Geomechanics and Engineering, 31(5), 439-452. https://doi.org/10.12989/gae.2022.31.5.439.
  24. Zhou, J.F., Zheng, Z.Y., Bao, T., Tu, B.X., Yu, J., Qin, C.B. (2023). Assessment of rigorous solutions for pseudo-dynamic slope stability: finite-element limit-analysis modelling. Journal of Central South University, 30, 2374-2391. https://doi.org/10.1007/s11771-023-5370-0.
  25. Ji, J., Liao, H.J. (2014). Sensitivity-based reliability analysis of earth slopes using finite element method. Geomechanics and Engineering, 6(6), 545-560. https://doi.org/10.12989/gae.2014.6.6.545.
  26. Smith, C., Gilbert, M. (2007). Application of discontinuity layout optimization to plane plasticity problems. Proceedings of the Royal Society of London A Mathematical Physical & Engineering Sciences, 463(2086), 2461-2484. https://doi.org/10.1098/rspa.2006.1788.
  27. Cheng, Y.M. (2003). Locations of critical failure surface and some further studies on slope stability analysis. Computers and Geotechnics, 30(3), 255-267. https://doi.org/10.1016/S0266-352X(03)00012-0.
  28. Zolfaghari, A.R., Heath, A.C., Mccombie, P.F. (2005). Simple genetic algorithm search for critical noncircular failure surface in slope stability analysis. Computers and Geotechnics, 32(3), 139-152. https://doi.org/10.1016/j.compgeo.2005.02.001.
  29. Cheng, Y.M., Li, L., Chi, S.C., Wei, W.B. (2007). Particle swarm optimization algorithm for the location of the critical non-circular failure surface in two-dimensional slope stability analysis. Computers and Geotechnics, 34(2), 92-103. https://doi.org/10.1016/j.compgeo.2006.10.012.
  30. Cheng, Y.M., Lau, C.K. (2008). Slope Stability Analysis And Stabilization. Routledge, London, UK.
  31. Smith, C., Gilbert, M. (2010). Advances in computational limit state analysis and design. Proceedings of GeoFlorida Advances in Analysis, Modeling & Design, West Palm Beach, FL, USA, February.
  32. Bishop, A.W. (1955). The use of the slip circle in the stability analysis of earth slopes. Géotechnique, 5(1), 7-17. https://doi.org/10.1680/geot.1955.5.1.7.
  33. Spencer, E. (1967). A method of analysis of the stability of embankments assuming parallel inter-slice forces. Géotechnique, 17, 11-26. https://doi.org/10.1680/geot.1968.18.3.384.
  34. Morgenstern, N., Price, V.E. (1965). The analysis of the stability of general slip surfaces. Géotechnique, 15(1), 79-93. https://doi.org/10.1680/geot.1965.15.1.79.
  35. Cheng, Y.M., Law, C.W., Liu, L.L. (2024). Analysis, design and construction of foundations, (2nd Ed.). CRC Press, Boca Raton, FL, USA.
  36. Geostudio (2019). [Computer Software]. GEOSLOPE International, Calgary, AB, Canada.
  37. Plaxis2D (2022). [Computer Program]. Bentley Systems Incorporated, Exton, PA, USA.
  38. LimitState GEO (2013). [Computer Program]. LimitState Ltd., Sheffield, UK.
  39. GEO-SLOPE International Ltd. (2019). Stability modelling with SLOPE/W 2019 version: an engineering methodology [Computer Program]. GEO-SLOPE International Ltd., Calgary, AB, Canada.
  40. Huang, L., Leung, Y.F. (2021). Reliability assessment of slopes with three-dimensional rotated transverse anisotropy in soil properties. Canadian Geotechnical Journal, 58(9), 1365-1378. https://doi.org/10.1139/cgj-2019-0611.
  41. Florkiewicz, A., Kubzdela, A. (2013). Factor of safety in limit analysis of slopes. Geomechanics and Engineering, 5(5), 485-497. https://doi.org/10.12989/gae.2013.5.5.485.
  42. Huang, L., Leung, Y.F., Liu, W., Pan, Q. (2020). Reliability of an engineered slope considering the Regression Kriging (RK)-based conditional random field. HKIE Transactions, 27(4), 183-194. https://doi.org/10.33430/V27N4THIE-2020-0004.
  43. Slide (2015). [Computer Program]. Rocscience Incorporated, Toronto, ON, Canada.
  44. Cheng, Y.M. (2007). Global optimization analysis of slope stability by simulated annealing with dynamic bounds and dirac function. Engineering Optimization, 39(1), 17-32. https://doi.org/10.1080/03052150600916294.