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Design Charts for the Stability Analysis of Unsaturated Soil Slopes

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Abstract

Simple limit equilibrium analyses can be performed to determine the Factor of Safety (FOS) against slope failure of unsaturated soil slopes. However, many of the input parameters needed for these analyses are highly variable, and the FOS value obtained is critically dependent on assumptions made by the designer. This paper describes a suite of reliability analyses on unsaturated soil slopes performed using an invariant reliability model. The results are presented in design charts from which a designer can choose the FOS value required to ensure a given target reliability index for a slope. The approach ensures that despite the variability of input parameters the slope will have a probability of failure of 2.23% or less.

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Abbreviations

C :

Total cohesion

COV:

Coefficient of variation

E(X):

Mean value of vector X

FOS:

Factor of Safety

P f :

Probability of failure

X:

Vector of variables

\( \overline{\text{X}} \) :

Vector of reduced variables

W :

The weight of a slice of the slope

c′:

Effective cohesion of soil

g(X):

Limit state function defined with vector [X]

\( g (\overline{\text{X}} ) \) :

Limit state function defined with reduced variables

h :

Wetting front depth

r :

Radius in polar coordinate

u a :

Pore air pressure

u w :

Pore water pressure

α:

Slope angle

β:

Reliability index

βHL :

Reliability index defined with Hasofer–Lind method

γ:

Unit weight of soil

ϕ′:

Friction angle of soil

ϕb :

Angle indicating the rate of increase in shear strength relative to the matric suction

θ:

Angle in polar coordinates

σ(X):

Standard deviation of vector X

σ n :

Total normal stress on the failure plane

τ:

Shear strength of unsaturated soils

∂:

Partial differential

References

  • Babu GL, Murthy DS (2005) Reliability analysis of unsaturated soil slopes. J Geotech Geoenviron Eng ASCE 131(11):1423–1428

    Article  Google Scholar 

  • Benjamin JR, Cornell CA (1970) Probability, statistics, and decision for civil engineers. McGraw-Hill, New York

    Google Scholar 

  • Cho SE, Lee SR (2001) Instability of unsaturated soil slopes due to infiltration. Comput Geotech 28(3):185–208

    Article  Google Scholar 

  • Chowdhury R, Flentje P (2003) Role of slope reliability analysis in landslide risk management. Bull Eng Geol Environ 62:41–46

    Google Scholar 

  • Doherty P, Casey P, Gavin K (2007) Suitability of Macamore clay as an embankment fill and the role of soil suction in embankment stability. In: Proceedings of the 3rd national bridge and transportation infrastructure symposium, Dublin

  • Eurocode 7 (2004) Geotechnical design—Part 1. European Committee for Standardisation, Brussels

    Google Scholar 

  • Fourie AB, Owe DR, Blight GE (1999) The effect of infiltration on the stability of the slopes of a dry ash dump. Geotechnique 49(1):1–13

    Article  Google Scholar 

  • Fredlund DG, Rahardjo H (1993) Soil mechanics for unsaturated soils. John Wiley, New York

    Google Scholar 

  • Fredlund DG, Morgenstern RA, Widger RA (1978) The shear strength of unsaturated soils. Can Geotech J 15(3):313–321

    Article  Google Scholar 

  • Gasmo JM, Rahardjo H, Leong EC (2000) Infiltration effects on stability of a residual soil slope. Comput Geotech 26(2):145–165

    Article  Google Scholar 

  • Gavin K, Xue JF (2008) A simple approach to analyze infiltration into unsaturated slopes. Comput Geotech 35(2):223–230

    Article  Google Scholar 

  • Gavin K, Xue JF (2009) Use of a genetic algorithm to perform reliability analysis of unsaturated soil slopes. Geotechnique. doi:10.1680/geot.8.T.004

  • Hasofer AM, Lind NC (1974) Exact and invariant second-moment code format. J Eng Mech Div, ASCE 100, EM1, 11:111–121

    Google Scholar 

  • Ng CW, Shi Q (1998) A numerical investigation of the stability of unsaturated soil slopes subjected to transient seepage. Comput Geotech 22(1):1–28

    Article  Google Scholar 

  • Paikowsky SG, Birgisson M, Mcvay M, Nguyen T (2004) Load and resistance factor design (LRFD) for deep foundations. Transportation Research Board, Washington, D.C

    Google Scholar 

  • Springman SM, Jommi C, Teysseire P (2003) Instability on moraine slopes induced by loss of suction: a case history. Geotechnique 53(1):3–10

    Google Scholar 

  • USACE (1997) ETL 1110-2-547. Introduction to probability and reliability methods for use in geotechnical engineering. U.S. Army Corps Engineers Document

  • USACE (1999) ETL 1110-2-556. Risk-based analysis in geotechnical engineering for support of planning studies, Appendix A. U.S. Army Corps of Engineers Document

  • Val D, Bljuger F, Yankelevsky D (1996) Optimization problem solution in reliability analysis of reinforced concrete structures. Comput Struct 60(3):351–355

    Article  Google Scholar 

  • Whitman RV (1984) Evaluating calculated risk in geotechnical engineering. J Geotech Eng ASCE 110(2):143–188

    Article  Google Scholar 

  • Xue JF (2007) Reliability analysis and the simulation of rainfall infiltration into partly saturated soil slopes. School of Architecture, Landscape and Civil Engineering. Dublin, University College Dublin

  • Xue JF, Gavin K (2007) Simultaneous determination of critical slip surface and minimum reliability index for earth slopes. ASCE J Geotech Geoenviron Eng 133(7):878–886

    Article  Google Scholar 

  • Zhang LL, Zhang LM, Tang WH (2005) Rainfall-induced slope failure considering variability of soil properties. Geotechnique 55(2):183–188

    Google Scholar 

Download references

Acknowledgments

This project is funded by Iarnród Éireann. The authors wish to thank Mr. Brian Garvey, former Chief Civil Engineer with Iarnród Éireann for technical and financial assistance received. The second author was the recipient of a Geotechnical Trust Fund award from the Geotechnical Society of Ireland. We wish to thank Paul Doherty (PhD student at University College Dublin) for performing the Monte–Carlo simulations presented in this paper.

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Authors and Affiliations

  1. School of Architecture, Landscape and Civil Engineering, University College Dublin, Newstead Building, Dublin 4, Ireland

    Kenneth Gavin

  2. Monash University, Melbourne, VIC, Australia

    Jianfeng Xue

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  1. Kenneth Gavin
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  2. Jianfeng Xue
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Correspondence to Kenneth Gavin.

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Gavin, K., Xue, J. Design Charts for the Stability Analysis of Unsaturated Soil Slopes. Geotech Geol Eng 28, 79–90 (2010). https://doi.org/10.1007/s10706-009-9282-z

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