Influence of the spatial variability of the root cohesion on a slope-scale stability model: a case study of residual soil slope in Thailand

  • Thanh Son Nguyen
  • Suched LikitlersuangEmail author
  • Apiniti Jotisankasa
Original Paper


The bioengineering method using vegetation is an ecological approach for slope stabilisation. However, due to a large variability of vegetation root patterns, a precise quantification of root reinforcement is relatively difficult, leading to a reluctance to use such a technique in practice. This paper presents a probabilistic framework for slope stability analysis considering the spatial variability of root reinforcement. A residual soil slope under a heavy rainfall event was used to model the seepage and stability analysis. The effect of root reinforcement was considered through an additional soil shear strength or root cohesion. Typical characteristics of the root reinforcement of vetiver grass (Chrysopogon zizanioides) in Thailand were assumed in the analysis. A probabilistic analysis was performed considering both stationary and non-stationary random fields of root cohesion. The results indicated that the failure of the vegetated slope could occur when the variance coefficient of the root cohesion was more than a critical value (a critical cov = 0.45 for the uniformly distributed root cohesion case and a critical cov = 0.32 for the case of linear decrease of root cohesion in this particular slope). In practice, the efficiency of the bioengineering method can be improved by controlling the variation of root cohesion within such limits.


Slope stability Probabilistic analysis Random field Vegetation Root cohesion 



This research was supported by the Thailand Research Fund Grant No. DBG-6180004 and the Ratchadapisek Sompoch Endowment Fund (2017), Chulalongkorn University (760003-CC). The first author would like to acknowledge the Ratchadapisek Sompot Fund (2018) for a Postdoctoral Fellowship. Field instrumentation and monitoring works were funded by the Kasetsart University Research and Development Institute (KURDI). The work was also carried out under the research and development project on landslide prevention and protection according to the Royal Initiatives of the Chaipattana Foundation.


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Geotechnical Research Unit, Department of Civil Engineering, Faculty of EngineeringChulalongkorn UniversityBangkokThailand
  2. 2.Department of Civil Engineering, Faculty of EngineeringKasetsart UniversityBangkokThailand

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