Performance estimation of a shallow foundation on an unsaturated expansive soil slope subjected to rainfall infiltration

In the last two decades, there has been a significant increase in infrastructure development on slopes of hilly regions of the world, due to population growth. There are many infrastructures on unsaturated expansive slopes, especially in semi-arid and arid regions. Rainfall infiltration is one of the major factors that contributes to the slope and infrastructure foundations failures on hilly slopes with unsaturated expansive soils. In the current study, a rational approach is proposed considering the combined influence of the foundation-slope behavior based on the principles of unsaturated soil mechanics. This is achieved by a novel numerical modelling approach using the commercial software Geo-studio to investigate the performance of strip foundation located on the top of the unsaturated expansive soil slope subjected to various rainfall infiltration conditions. Hydro-mechanical coupling analysis is conducted to evaluate the rainfall water infiltration influence combined with slope stability analysis using limit equilibrium method. Comparisons are made between both the foundation bearing capacity, slope stability before and after rainfall water infiltration. Different failure mechanisms of the foundation and slope system are presented with and without foundation loading for various rainfall scenarios. Results summarized in this paper are helpful for the geotechnical engineers for understanding the performance of shallow foundations on unsaturated expansive soil slopes considering the influence of rainfall infiltration conditions.

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Analysis on the Impact of Expansive Soil Slope Stability by Rainfall Infiltration

2018 International Conference on Engineering Simulation and Intelligent Control (ESAIC) ◽

10.1109/esaic.2018.00014 ◽

2018 ◽

Author(s):

Huang Zhi-Fang

Keyword(s):

Slope Stability ◽

Expansive Soil ◽

Rainfall Infiltration ◽

Soil Slope ◽

The Impact

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Field study of rainfall infiltration into a grassed unsaturated expansive soil slope

Canadian Geotechnical Journal ◽

10.1139/t07-001 ◽

2007 ◽

Vol 44 (4) ◽

pp. 392-408 ◽

Cited By ~ 64

Author(s):

Tony LT Zhan ◽

Charles WW Ng ◽

Del G Fredlund

Keyword(s):

Field Study ◽

Water Content ◽

Pore Water ◽

Surface Runoff ◽

Expansive Soil ◽

Rainfall Infiltration ◽

Slope Instability ◽

Simulated Rainfall ◽

Soil Slope ◽

Unsaturated Expansive Soil

A full-scale field study was conducted to investigate the effects of rainfall infiltration on a natural grassed expansive soil slope in China. A 16 m wide × 28 m long area was selected for instrumentation. The instrumentation included jet-filled tensiometers, moisture probes, a tipping bucket rain gauge, and a vee-notch flow meter. One artificial rainfall event amounting to about 370 mm rain depth in total was applied to the slope. The monitored results suggested that there was about a 3 day delay in the response of surface runoff, pore-water pressure, and water content to the commencement of the simulated rainfall. The depth of influence of the rainfall, depending on the elevation along the slope, ranged from 2.8 to 3.5 m. Positive pore-water pressures were measured within the influence depth, and there existed significant subsurface downslope flow at the end of the simulated rainfall, particularly near the lower part of the slope. A comparison of infiltration rates between the grassed area and a bare area nearby indicated that the presence of grass significantly increased the infiltration rate and reduced surface runoff. The cracks and fissures developed in the unsaturated expansive soil played an important role in the hydrological process.Key words: expansive soil, slope instability, infiltration, vegetation cover, grass, soil suction, water content, unsaturated soil.

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The Effect of Rainfall Infiltration Time to the Unsaturated Soil Slope Stability

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.71-78.4864 ◽

2011 ◽

Vol 71-78 ◽

pp. 4864-4867

Author(s):

Guang Hua Cai ◽

Hai Jun Lu ◽

Wei He ◽

Long Guan ◽

Wei Qi Xu

Keyword(s):

Slope Stability ◽

Pore Water ◽

Pore Water Pressure ◽

Limit Equilibrium ◽

Water Pressure ◽

Rainfall Infiltration ◽

Soil Slope ◽

Soil Permeability ◽

Rainfall Condition ◽

Pressure Changes

Rainfall infiltration is currently one of the important factors in studying the soil-slope stability. By using saturated-unsaturated seepage theory, the traditional limit equilibrium method and so on, analyze the water content and the pore-water pressure changes under the rainfall condition, then analyze the influence mechanism of the slope stability. Through the Seep/W and the Slope/W of the GEO-Slope software, do the numerical simulation of the slope stability under the rainfall condition, to seek the distribution of pore-water pressure on the rainfall situation and the influence of the seepage field from various parameters such as rainfall intensity and the soil permeability coefficient, thus to study the slope stability.

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Performance of an unsaturated expansive soil slope subjected to artificial rainfall infiltration

Géotechnique ◽

10.1680/geot.2003.53.2.143 ◽

2003 ◽

Vol 53 (2) ◽

pp. 143-157 ◽

Cited By ~ 109

Author(s):

C. W. W. Ng ◽

L. T. Zhan ◽

C. G. Bao ◽

D. G. Fredlund ◽

B. W. Gong

Keyword(s):

Expansive Soil ◽

Rainfall Infiltration ◽

Soil Slope ◽

Artificial Rainfall ◽

Unsaturated Expansive Soil

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Comparative Study of Rainfall Infiltration into a Bare and a Grassed Unsaturated Expansive Soil Slope

SOILS AND FOUNDATIONS ◽

10.3208/sandf.47.207 ◽

2007 ◽

Vol 47 (2) ◽

pp. 207-217 ◽

Cited By ~ 18

Author(s):

C.W.W. Ng ◽

L.T. Zhan

Keyword(s):

Comparative Study ◽

Expansive Soil ◽

Rainfall Infiltration ◽

Soil Slope ◽

Unsaturated Expansive Soil

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Analysis of Fissured Expansive Soil Slope Stability and its Reinforcement with Anti-Slippery Piles

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.275-277.1489 ◽

2013 ◽

Vol 275-277 ◽

pp. 1489-1492 ◽

Cited By ~ 1

Author(s):

Hui Sun ◽

Bo Hu ◽

Guo Qiang Zhang

Keyword(s):

Slope Stability ◽

Expansive Soils ◽

Limit Equilibrium ◽

Expansive Soil ◽

Water Diversion ◽

Soil Slope ◽

Water Diversion Project ◽

North Water ◽

Channel Slope ◽

The Stability

Fissure is one of the most important characteristics in expansive soil. It’s an important factor affecting slope stability in the expansive soil area. With the study of expansive soils typical channel slope fissured characters in the South-to-North Water Diversion Project, different impaction on slope stability such as location and inclination of the fissure are analyzed. By using the limit equilibrium method, the stability of expansive soil slope is analyzed; the most adverse condition of expansive soil slope is concluded. Then anti-slippery pile reinforcement in expansive soil channel slope is studied by using finite difference method. The research is of great significance to the construction and reinforcement of expansive soil slopes in South-to-North Water Diversion Project.

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