Stability Analysis of Slopes Subjected to Transient Unsaturated Seepage Effect Considering Hydromechanical Coupling Effect
Publication: International Journal of Geomechanics
Volume 22, Issue 6
Abstract
Analyzing the stability of slopes during rainfall can be critical in preventing landslide disasters. In this study, on the basis of the limit analysis method, a novel method for computing the safety factor of slopes considering transient unsaturated seepage effect is proposed, which considers the hydromechanical coupling effect. The proposed method is appropriate for vertical cut slopes which cannot be solved by the infinite slope analysis method. Two cases validate the proposed method. In the proposed method, the safety factor of slopes can be obtained by a simple optimization algorithm. The number of the independent variables of the proposed method is usually less than that of the limit-equilibrium method. The effect of hydrological parameters (the ratio of rainfall intensity to saturated permeability coefficient, desaturation coefficient, elasticity modulus related to suction), slope geometric parameters (slope angle and slope height), and soil shear strength parameters (effective cohesion and effective internal friction angle) on safety factor is also studied. The results show that the hydromechanical coupling has a great impact on slope stability, and the effect of shear strength parameters on slope stability is greater than that of geometric parameters. The hydrological parameters mainly control the degradation degree of slope safety factor over time. For actual slopes that do not completely satisfy the assumption of infinite slopes, too conservative results may be obtained by the infinite slope analysis method, resulting in huge economic waste in engineering construction.
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Notation
The following symbols are used in this paper:
- critical effective cohesion;
- c′, ϕ′
- effective cohesion and effective internal friction angle of soil;
- F
- elastic modulus of partially saturated porous medium related to soil suction;
- Fs
- slope safety factor;
- k
- permeability coefficient;
- ks
- saturated permeability coefficient;
- qa, qb
- rainfall intensity;
- t
- rainfall duration;
- α
- desaturation coefficient;
- β, H
- slope angle and slope height;
- γ
- unit weight of soil;
- ϑ, r
- polar angle and radius in polar coordinate system ϑ–r;
- ϑ0, ϑh, and β′
- three independent variables used to calculate slope safety factor;
- ψ
- pressure head;
- θs, θr
- saturated water content and residual water content;
- θ
- volumetric moisture; and
- σs
- suction stress.
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Published In
International Journal of Geomechanics
Volume 22 • Issue 6 • June 2022
Copyright
© 2022 American Society of Civil Engineers.
History
Received: Jul 9, 2021
Accepted: Jan 23, 2022
Published online: Apr 6, 2022
Published in print: Jun 1, 2022
Discussion open until: Sep 6, 2022
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