Hydro-mechanical coupling effect on surficial layer stability of unsaturated expansive soil slopes

Qi, Suitao; Vanapalli, Sai K.

doi:10.1016/j.compgeo.2015.07.006

Cited by 128 publications

(44 citation statements)

References 61 publications

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“…For a slope with a larger HC, the slope failures possibly take place under rainfall with a shorter duration and a greater intensity [8]. Those research works also concluded that when the rainfall intensity is greater than the saturated hydraulic conductivity of the surface soils, a runoff occurs along the slope surface [8,22].…”

Section: Introductionmentioning

confidence: 95%

“…The change of the area from unsaturated to saturated is caused by the advancement of the wetting front from the surface [4,5,9,13,[21][22][23] and groundwater table from depth [6][7][8][10][11][12][13][14][15][16][17][18][19][20]. Those processes were found to be the primary factors controlling the instability of slopes due to rainfall and were greatly affected by rainfall intensity (RI) and soil properties, especially by unsaturated soil hydraulic conductivity [4,[17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36]. The unsaturated soil hydraulic conductivity (HC) controls the transient seepage, the depth of rainfall infiltration, the changes in pore pressure during the rainfall event, and finally, affects the FOS.…”

Section: Introductionmentioning

confidence: 99%

“…The unsaturated soil hydraulic conductivity (HC) controls the transient seepage, the depth of rainfall infiltration, the changes in pore pressure during the rainfall event, and finally, affects the FOS. The effects of soil hydraulic conductivity on slope stability in the rainy season are usually assessed from the point of view of three topics: (1) the effects of changes in the value of soil hydraulic conductivity and rainfall intensity [17][18][19][20][21][22][23][24][25][26][27][28][29][30]; (2) the soil anisotropic HC and hydraulic hysteresis [31][32][33][34][35]; (3) the failure delay phenomenon due to the defense of HC and RI [36]. This research focuses on the overview and analysis of the first of these topics.…”

Section: Introductionmentioning

confidence: 99%

“…When building the relationship of rainfall intensity and unsaturated hydraulic conductivity by the ratio of RI/HC, the previous research analyzed the RI = HC [5], RI ≥ HC [19,22]; and RI < HC [8,17,21,23,26,29] cases. Setting up a boundary with RI = HC or RI ≥ HC and no pond [5,19,22], the development of a wetting front from the crest of the slope and the reduction of soil suction during rainfall were found to dominantly affect the slope stability. The development of the defense of the wetting front under increased rainfall intensity shortens the time required for the wetting front to reach the pore-water pressure and moisture content sensors.…”

Section: Introductionmentioning

confidence: 99%

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Assessing the Effects of Rainfall Intensity and Hydraulic Conductivity on Riverbank Stability

Duong

Yasuhara

2019

Water

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Riverbank failure often occurs in the rainy season, with effects from some main processes such as rainfall infiltration, the fluctuation of the river water level and groundwater table, and the deformation of transient seepage. This paper has the objective of clarifying the effects of soil hydraulic conductivity and rainfall intensity on riverbank stability using numerical analysis with the GeoSlope program. The initial saturation condition is first indicated as the main factor affecting riverbank stability. Analyzing high-saturation conditions, the obtained result can be used to build an understanding of the mechanics of riverbank stability and the effect of both the rainfall intensity and soil hydraulic conductivity. Firstly, the rainfall intensity is lower than the soil hydraulic conductivity; the factor of safety (FOS) reduces with changes in the groundwater table, which is a result of rainwater infiltration and unsteady state flow through the unsaturated soil. Secondly, the rainfall intensity is slightly higher than the soil hydraulic conductivity, the groundwater table rises slowly, and the FOS decreases with both changes in the wetting front and groundwater table. Thirdly, the rainfall intensity is much higher than the soil hydraulic conductivity, and the FOS decreases dominantly by the wetting front and pond loading area. Finally, in cases with no pond, the FOS reduces when the rainfall intensity is lower than hydraulic conductivity. With low hydraulic conductivity, the wetting front is on a shallow surface and descends very slowly. The decreasing of FOS is only due to transient seepage changes of the unsaturated soil properties by losing soil suction and shear strength. These obtained results not only build a clearer understanding of the filtration mechanics but also provide a helpful reference for riverbank protection.

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Section: Introductionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Assessing the Effects of Rainfall Intensity and Hydraulic Conductivity on Riverbank Stability

Duong

Yasuhara

2019

Water

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“…Soil with higher permeability allows more rainwater to infiltrate and flow into the soil slope resulting in a quick change of pore-water pressure from negative to positive [5]. The infiltration of rainwater increases water content and decreases matric suction in the soil [6][7][8][9]. During rainfall, soil suction dissipates due to the saturation of the soil.…”

Section: Introductionmentioning

confidence: 99%

The Rise of Groundwater Due to Rainfall and the Control of Landslide by Zero-Energy Groundwater Withdrawal System

Alsubal¹,

Sapari²,

Harahap³

2018

IJET

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Slope failure is a common issue in tropical countries. The rise of groundwater table due to rainfall is one of the main triggering factors. There are several methods for slope stabilization such as soil nailing, retaining walls, cut and fill, vegetation and so on. Most of those methods are costly and we are in need for stabilizing methods that are more economical and easier to construct. This article introduces a new method for slope stability. This method is examined numerically and experimentally. It is represented in an automatic zero-energy groundwater withdrawal system to enhance slope stability. The system is validated in a pre-fabricated model to ensure that it works on natural soil slope. The numerical simulation is performed in Soilworks software with coupled seepage-slope stability analysis using finite element methods to check the safety factor with and without the system. The effectiveness of this method is investigated with various rainfall intensities and soil permeabilities. The results for slopes with the application of groundwater withdrawal system are compared with the results without the system. The results demonstrate the effectiveness of the proposed method in reducing groundwater table and enhancing slope stability. The factor of safety for the slope with high soil permeability drops from 1.312 before the rainfall to 1.292 and 0.93 after the third rainfall event for the slope with and without pumping groundwater respectively. For soil slope with moderate soil permeability, the factor of safety deteriorates from 1.314 to 1.157 at the end of the third day, while it remains stable with pumping groundwater. Matric suction is highly increased at the crest of the slope due to pumping.

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A three‐dimensional limit equilibrium method for slope stability analysis integrating machine learning optimized intercolumn force function

Zhou

2023

Geological Journal

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A calculation of the safety factor is the basis of slope stability analysis. The three‐dimensional (3D) limit equilibrium method is one of the most effective safety calculation methods, and ignoring the partial shear force between columns is the most common calculation assumption, which will lead to an unreasonable safety factor. By constraining the range of the intercolumn shear function and the position of the action point of the force between columns and integrating machine learning to optimize the net moment of the column, the simulated annealing algorithm is used to obtain the intercolumn shear function under the minimum net moment, and the safety factor is calculated by using boundary conditions. Finally, proving the accuracy of this method by calculating two examples of commonly used slopes. Example A verifies that the result of the proposed method is more conservative than that of other 3D calculation methods and that the coordinates of the action point of the intercolumn forces in the x and y directions have little influence on safety factor. Example B verifies the applicability of this method to various slope forms. This method fully considers the stress of soil under actual conditions, making the calculation results more reasonable.

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Hydro-mechanical coupling effect on surficial layer stability of unsaturated expansive soil slopes

Cited by 128 publications

References 61 publications

Assessing the Effects of Rainfall Intensity and Hydraulic Conductivity on Riverbank Stability

Assessing the Effects of Rainfall Intensity and Hydraulic Conductivity on Riverbank Stability

The Rise of Groundwater Due to Rainfall and the Control of Landslide by Zero-Energy Groundwater Withdrawal System

A three‐dimensional limit equilibrium method for slope stability analysis integrating machine learning optimized intercolumn force function

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