Volume 3, Issue 1 — Year 2026 — Article e100057

ISSN (Online): 3115-8129 Biannually

Prediction of Slope Instability in Residual and Colluvial Soils using Field-derived Shear Strength Parameters

Article Type: Research
Pages: e100057
DOI: https://doi.org/10.22034/CGEL.3.1.e100057
Crossmark
Open Access
Authors
Affiliations
  1. School of Earth, Environment and Sustainability, University of Leeds, England LS2 9JT, UK
  2. Civil Engineering Department, Visvesvaraya Technological University, Belagavi 590018, India
Corresponding author
Email: drmartin.cross58@gmail.com
ORCID: 0009-0002-8070-507X
Received: 08 March 2026 / Accepted: 16 April 2026 / Published: 25 May 2026
Abstract

This study investigates slope instability in residual and colluvial soils using field-derived shear strength parameters from the South Pennines, UK. A total of 45 in situ open-sided direct shear box tests were conducted across three slope sections (upper 33°, middle 24°, lower 16°), with 15 tests per section under normal stresses ranging from 0 to 20 kN/m². The results show that the upper and middle slopes, composed of coarser materials, yielded higher friction angles (φ′ = 38.5°–42.8°) and low cohesion (c′ = 0–6.5 kPa), whereas the lower slope, dominated by finer soils, exhibited lower friction angles (φ′ = 25.2°–29.4°) and slightly higher cohesion (c′ = 2.0–4.8 kPa). Regression analysis indicates a strong relationship between φ′ and slope angle (R² = 0.76), while c′ shows moderate correlation with vegetation cover (R² = 0.58). Stability modelling using an infinite slope approach produced limiting angles between 17.2° and 22.4°, consistent with observed shallow failures in the field. The findings demonstrate that field-measured shear strength parameters provide a reliable basis for predicting slope instability. This approach captures the effects of soil heterogeneity and vegetation, offering a practical method for slope hazard assessment in similar upland terrains.

Keywords

Residual soils, Colluvial soils, Shear strength parameters, Slope instability, Field direct shear testing

Data availability statement

The data supporting the findings of this study are available from the corresponding author upon reasonable request. No publicly archived dataset was generated.

Funding

This research received no external funding.

Highlights
  • Field tests define slope shear strength behavior
  • Friction angle relates strongly to slope angle
  • Results improve slope instability prediction
References
  1. Aramaki S., Kitazono Y., Suzuki A., Kajiwara M. (1992). Application of direct shear test to analysis of tertiary landslides along a bedding plane. Soils and Foundations, 32(1), 1-12. https://doi.org/10.3208/sandf1972.32.1.
  2. Azarafza M., Akgün H., Ghazifard A., Asghari-Kaljahi E., Rahnamarad J., Derakhshani R. (2021). Discontinuous rock slope stability analysis by limit equilibrium approaches–a review. International Journal of Digital Earth, 14(12), 1918-1941. https://doi.org/10.1080/17538947.2021.1988163.
  3. Azarafza M., Bonab M.H., Derakhshani R. (2022). A novel empirical classification method for weak rock slope stability analysis. Scientific Reports, 12(1), 14744. https://doi.org/10.1038/s41598-022-19246-w.
  4. Bhat D.R. (2022). Shear rate effect on residual strength of typical clay soils. Innovative Infrastructure Solutions, 7(1), 36. https://doi.org/10.1007/s41062-021-00629-3.
  5. Cazzuffi D., Crippa E. (2005). Contribution of vegetation to slope stability: an overview of experimental studies carried out on different types of plants. Erosion of Soils and Scour of Foundations, pp. 1-12. https://doi.org/10.1061/40781(160)9.
  6. Clark C.D, Ely J.C., Greenwood S.L., Hughes A.L.C, Meehan R., Barr J.D., Bateman M.D., Bradwell T., Doole J., Evans D.J.A., Joran C.J., Monteys X., Pellicer X.M., Sheeyy M. (2017). BRITICE Glacial Map, version 2: a map and GIS database of glacial landforms of the British-Irish Ice Sheet. Boreas, 47 (1), 11-18, https://doi.org/10.1111/bor.12273.
  7. Collinson J., Rosen B.R. (2024). The Southern Pennines. Liverpool University Press, Liverpool, England, UK.
  8. Cross M. (2010). The use of a field open-sided direct shear box for the determination of the shear strength of shallow residual and colluvial soils on hillslopes in the south Pennines, Derbyshire. North West Geography, 10, 8-18.
  9. Cross M. (2011). Slope geomorphology and threshold slopes at Callow Bank, Hathersage, Derbyshire. Mercian Geologist, 17(4), 243-248.
  10. Cross M. (2019). Sensitivity analysis of shallow planar landslides in residual soils on south Pennine hillslopes, Derbyshire, UK. Bulletin of Engineering Geology and the Environment, 78, 1855-1872. https://doi.org/10.1007/s10064-017-1195-0.
  11. Dai M., Cui D., Chen Q., Wei J., Wang J., Zhang G. (2024). Reactivated mechanism of a slow-moving landslide with two shear zones based on ring shear test and in situ monitoring. Landslides, 21(11), 2617-2634. https://doi.org/10.1007/s10346-024-02320-x.
  12. Daramola A.M., Satyanaga A., Adejumo B.D., Kim Y., Qian Z., Kim J. (2025). Real-Time scanning curve of soil–Water characteristic curve for sustainability of residual soil slopes. Sustainability, 17(5), 1803. https://doi.org/10.3390/su17051803.
  13. Di Matteo L., Valigi D., Ricco R. (2013). Laboratory shear strength parameters of cohesive soils: variability and potential effects on slope stability. Bulletin of Engineering Geology and the Environment, 72(1), 101-106. https://doi.org/10.1007/s10064-013-0459-6.
  14. Eid H.T., Rabie K.H., Wijewickreme D. (2016). Drained residual shear strength at effective normal stresses relevant to soil slope stability analyses. Engineering Geology, 204, 94-107. https://doi.org/10.1016/j.enggeo.2016.02.003.
  15. Evans I.S. (2024). A note on glacial cirques and Late-glacial moraines in the Pennines, northern England. Geoconcept Journal, 1, 31-44.
  16. Evans, D.J.A., Clark, C.D. Wishart, A.M. 2005. The last British Ice Sheet: A review of the evidence utilized in the compilation of the Glacial Map of Britain. Earth-Science Reviews, 70 (3-4), 253-312.
  17. Fei J., Jie Y., Sun X., Xiong H. (2020). Physical interpretation of shear-rate behaviour of soils and geotechnical solution to the coefficient of start-up friction with low inertial number. Scientific Reports, 10(1), 12162. https://doi.org/10.1038/s41598-020-69023-w.
  18. Head K.H. (1981). Manual Of Soil Laboratory Testing, Vol 2: Permeability, Shear Strength & Compressibility Tests. John Wiley & Sons, New Jersey, USA.
  19. Heidemann M., Bressani L.A., Flores J.A. (2020). Residual shear strength of a residual soil of granulite. Soils and Rocks, 43(1), 31-41. https://doi.org/10.28927/SR.431031.
  20. Johnson R.H. (1980). Hillslope stability and landslide hazard—A case study from Longdendale, north Derbyshire, England. Proceedings of the Geologists' Association, 91(4), 315-325. https://doi.org/10.1016/S0016-7878(80)80026-5.
  21. Jones D.K.C, Lee E.M. (1994). Landsliding in Great Britain. Department for Environment, Food & Rural Affairs, London, England, UK.
  22. Jotisankasa A., Mairaing W. (2009). Suction-monitored direct shear testing of residual soils from landslide-prone areas. Journal of Geotechnical and Geoenvironmental Engineering, 136(3), 533-537. https://doi.org/10.1061/(ASCE)GT.1943-5606.0000225.
  23. Kholghifard M., Ahmad K. (2021). Effect of matric suction and density on yield stress, compression index and collapse potential of unsaturated granite soil. KSCE Journal of Civil Engineering, 25(8), 2847-2854. https://doi.org/10.1007/s12205-021-0830-2.
  24. Kimura S., Nakamura S., Vithana S.B. (2015). Influence of effective normal stress in the measurement of fully softened strength in different origin landslide soils. Soil and Tillage Research, 145, 47-54. https://doi.org/10.1016/j.still.2014.07.018.
  25. Lee E.M., Giles D.P. (2020). Landslide and slope stability hazard in the UK. In: Geological Hazards in the UK: Their Occurrence, Monitoring and Mitigation – Engineering Group Working Party Report, Chapter 4, https://doi.org/10.1144/EGSP29.4.
  26. Lian B., Wang X., Peng J., Huang Q. (2020). Shear rate effect on the residual strength characteristics of saturated loess in naturally drained ring shear tests. Natural Hazards and Earth System Sciences, 20(10), 2843-2856. https://doi.org/10.5194/nhess-20-2843-2020.
  27. Liu X., Zhang X., Kong L., Chen C., Yin S. (2023). Influence of intermediate principal stress on shear strength of natural granite residual soil. Journal of Geotechnical and Geoenvironmental Engineering, 149(5), 06023003. https://doi.org/10.1061/JGGEFK.GTENG-1051.
  28. Meehan C.L., Brandon T.L., Duncan J.M., Tiwari B. (2010). Direct shear testing of polished slickensided surfaces. Landslides, 7(2), 157-167. https://doi.org/10.1007/s10346-010-0199-7.
  29. Meehan C.L., Tiwari B., Brandon T.L., Duncan J.M. (2011). Triaxial shear testing of polished slickensided surfaces. Landslides, 8(4), 449-458. https://doi.org/10.1007/s10346-011-0263-y.
  30. Meisina C., Scarabelli S. (2007). A comparative analysis of terrain stability models for predicting shallow landslides in colluvial soils. Geomorphology, 87(3), 207-223. https://doi.org/10.1016/j.geomorph.2006.03.039.
  31. Mesri G., Huvaj-Sarihan N. (2012). Residual shear strength measured by laboratory tests and mobilized in landslides. Journal of Geotechnical and Geoenvironmental Engineering, 138(5), 585-593. https://doi.org/10.1061/(ASCE)GT.1943-5606.0000624.
  32. Miao H., Wang G. (2021). Effects of clay content on the shear behaviors of sliding zone soil originating from muddy interlayers in the Three Gorges Reservoir, China. Engineering Geology, 294, 106380. https://doi.org/10.1016/j.enggeo.2021.106380.
  33. Nguyen T.S., Likitlersuang S. (2019). Reliability analysis of unsaturated soil slope stability under infiltration considering hydraulic and shear strength parameters. Bulletin of Engineering Geology and the Environment, 78(8), 5727-5743. https://doi.org/10.1007/s10064-019-01513-2.
  34. Nguyen T.S., Phan T.N., Likitlersuang S., Bergado D.T. (2022). Characterization of stationary and nonstationary random fields with different copulas on undrained shear strength of soils: Probabilistic analysis of embankment stability on soft ground. International Journal of Geomechanics, 22(7), 04022109. https://doi.org/10.1061/(ASCE)GM.1943-5622.0002444.
  35. Pei X., Zhang X., Guo B., Wang G., Zhang F. (2017). Experimental case study of seismically induced loess liquefaction and landslide. Engineering Geology, 223, 23-30. https://doi.org/10.1016/j.enggeo.2017.03.016.
  36. Qi C., Shen, M., Zhang Z., Li J., Huang R., Guo C., Dong L. (2025). Case study on application of polymer in slope reinforcement and field direct shear test. Results in Engineering, 27, 106218. https://doi.org/10.1016/j.rineng.2025.106218.
  37. Rahardjo H., Satyanaga A., Leong E.C., Ng Y.S., Pang H.T.C. (2012). Variability of residual soil properties. Engineering Geology, 141-142, 124-140. https://doi.org/10.1016/j.enggeo.2012.05.009.
  38. Renani H.R, Martin C.D. (2020). Slope stability analysis using equivalent Mohr–Coulomb and Hoek–Brown criteria. Rock Mechanics and Rock Engineering, 53(1), 13-21. https://doi.org/10.1007/s00603-019-01889-3.
  39. Shibasaki T., Matsuura S., Okamoto T. (2017). Temperature-dependent residual shear strength of landslide soils. Journal of Geophysical Research: Solid Earth, 122(2), 1449-1469. https://doi.org/10.1002/2016JB013241.
  40. Stark T.D., Choi H., McCone S. (2005). Drained shear strength parameters for analysis of landslides. Journal of Geotechnical and Geoenvironmental Engineering, 131(5), 575-588. https://doi.org/10.1061/(ASCE)1090-0241(2005)131:5(575).
  41. Stark T.D., Hussain M. (2012). Empirical correlations: Drained shear strength for slope stability analyses. Journal of Geotechnical and Geoenvironmental Engineering, 139(6), 853-862. https://doi.org/10.1061/(ASCE)GT.1943-5606.0000824.
  42. Tian D., Zheng H. (2023). The generalized Mohr-Coulomb failure criterion. Applied Sciences, 13(9), 5405. https://doi.org/10.3390/app13095405.
  43. Tian Z., Pan Y., Chen M., Zhang S., Chen Y. (2023). The relationships between fractal parameters of soil particle size and heavy-metal content on alluvial-proluvial fan. Journal of Contaminant Hydrology, 254, 104140. https://doi.org/10.1016/j.jconhyd.2023.104140.
  44. Tiwari B., Ajmera B. (2023). Advancements in shear strength interpretation, testing, and use for landslide analysis. Progress in Landslide Research and Technology, 2(2), 3-54. https://doi.org/10.1007/978-3-031-44296-4_1.
  45. Waltham A.C., Dixon N.R. (2000). Movement of the Mam tor landslide, Derbyshire, UK. Quarterly Journal of Engineering Geology and Hydrogeology, 33, 105-123. 10.1144/qjegh.33.2.105.
  46. Wang Z., Qi C., Zhang Z., Huang R., Guo C., Dong L., Zheng R. (2025). Improved in-situ direct shear test of rock mass structural plane and its application to stability analysis of bedding slope. Case Studies in Construction Materials, 23, e04976. https://doi.org/10.1016/j.cscm.2025.e04976.
  47. Zádorová T., Penížek V. (2018). Formation, morphology and classification of colluvial soils: a review. European Journal of Soil Science, 69(4), 577-591. https://doi.org/10.1111/ejss.12673.
How to cite
Cross, M., & Dulal, S. (2026). Prediction of Slope Instability in Residual and Colluvial Soils using Field-derived Shear Strength Parameters. Civil and Geoengineering Letters, 3(1), e100057. https://doi.org/10.22034/CGEL.3.1.e100057
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