Abstract
In general, soil properties, including shear strength and hydraulic parameters, are characterised as a spatial variability. This paper aims to investigate the effect of spatial variability of the soil properties on slope stability during rainfall infiltration. The effective friction angle, saturated hydraulic conductivity, and soil water characteristic curve parameters of sand are simulated using random field theory. A seepage analysis is conducted using the random finite element method to obtain pore water pressure distribution. A stability analysis is performed to show the variation of safety factors and failure probability. The results show that the random field of the soil-water characteristic curve produces a significant variation of pore water pressure, while the random field of the effective friction angle is the most important parameter for probabilistic stability analysis.
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Abbreviations
- θ :
-
Volumetric water content
- ψ :
-
Suction
- σ :
-
Normal total stress
- ρ(τ x ,τ y ) :
-
Correlation coefficient between two arbitrary points in a soil layer
- ξ :
-
Independent standard normal samples
- β :
-
Slope angle
- δ :
-
Normalised correlation length
- ϕ’ :
-
Effective friction angle
- ρ a,n :
-
Cross-correlation coefficient between the SWCC parameters a & n
- τ f :
-
Shear strength of saturated-unsaturated soils
- γ i :
-
Average unit weight of slice ith
- α i :
-
Angle of the base of the ith slice
- μ lnz :
-
Mean of a normal distribution
- σ lnz :
-
Standard deviation of a normal distribution
- θ r :
-
Residual volumetric water content
- θ s :
-
Saturated volumetric water content
- τ x :
-
Absolute distances between two points in the horizontal direction
- τ y :
-
Absolute distances between two points in the vertical direction
- μ z :
-
Mean of a lognormal distribution
- σ z :
-
Standard deviation of a lognormal distribution
- a, n, m :
-
SWCC parameters
- b i :
-
Width of the ith slice
- \( {C}_{n_e\times {n}_e} \) :
-
Correlation matrix
- h :
-
Total pressure head
- H :
-
Height of slope
- h i :
-
Height of the ith slice
- I :
-
Indicator function
- k :
-
Hydraulic conductivity
- k s :
-
Saturated permeability
- k x :
-
Hydraulic conductivity in the horizontal direction
- k y :
-
Hydraulic conductivity in the vertical direction
- L :
-
Width of slope
- L 1 , L 2 :
-
Lower triangular matrices
- l x :
-
Horizontal correlation length
- l y :
-
Vertical correlation length
- m s :
-
random field numerical identifier
- n e :
-
Random field elements
- n M :
-
Number of realisations
- n s :
-
Total number of slices
- P f :
-
Failure probability
- q :
-
Applied flux boundary
- R :
-
Cross-correlation matrix
- u a :
-
Pore air pressure
- u w :
-
Pore water pressure
- W i :
-
Weight of the ithslice
- x :
-
Horizontal direction
- \( {X}_i^G \) :
-
Cross-correlation standard Gaussian random field
- y :
-
Vertical direction
- Z i(x, y):
-
Lognormal random field
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Acknowledgements
This research was supported by the Thailand Research Fund Grant No. DBG-6180004 and the Ratchadapisek Sompoch Endowment Fund (2019), Chulalongkorn University (762003-CC). The first author would like to acknowledge the Ratchadapisek Sompote Fund (2019) for Postdoctoral Fellowship, Chulalongkorn University. The second author would like to acknowledge the Royal Society-Newton Advanced Fellowship (NA170293).
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Nguyen, T.S., Likitlersuang, S. Reliability analysis of unsaturated soil slope stability under infiltration considering hydraulic and shear strength parameters. Bull Eng Geol Environ 78, 5727–5743 (2019). https://doi.org/10.1007/s10064-019-01513-2
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DOI: https://doi.org/10.1007/s10064-019-01513-2