以水力耦合模式評估土壤水力傳導異向性對邊坡穩定之研究

Translated title of the contribution: Effects of Anisotropic Soil Hydraulic Conductivity on Slope Stability Using a Coupled Hydromechanical Framework

Yi Jin Tsai, Hsin-fu Yeh

Research output: Contribution to journalArticle

Abstract

In studies on the effect of rainfall infiltration on slope stability, soil hydraulic conductivity has usually been assumed to be isotropic to simplify the analysis when using a numerical model; studies have ignored the influence of anisotropic hydraulic conductivity. Therefore, this study established a coupled hydromechanical framework using transient seepage and slope stability analyses to investigate the effects of changes in hydraulic conductivity isotropy on rainfall infiltration and slope safety at various locations (i.e., at the top of the slope, on the slope, and at the toe of the slope). The results showed that when the vertical hydraulic conductivity (ky) was constant, increase in the horizontal to hydraulic conductivity (kx) (an increase in anisotropy) caused the seepage of rainfall to tend to infiltrate into the interior of the slope. This resulted in the soil on top of the slope (near the slope) and on the slope being more easily influenced by rainfall, thereby leading to soil instability. The change on the slope was the most significant. When the anisotropic ratio kr (= kx/ky) increased from 1 to 100, the wetting zones on the slopes of loam, silt, and clay deepened by 23.3%, 33.3%, and 50%, respectively. However, increased kr led to a slower infiltration rate in the vertical direction at the toe of the slope. Comparing the results of kr = 1 and kr = 100, the thickness of the wetting zones at the toe of the slopes of loam and silt decreased by 23.3% and 30.0%, respectively. In the case of the clay slope, kr changes did not reach significance because of its poor permeability. Therefore, this study suggests considering the effects of soil hydraulic conductivity anisotropy when estimating slope stability, to precisely determine the effect of rainfall on slopes.

Original languageChinese
Pages (from-to)167-177
Number of pages11
JournalJournal of Chinese Soil and Water Conservation
Volume49
Issue number3
DOIs
Publication statusPublished - 2018 Sep 1

Fingerprint

Slope stability
Hydraulic conductivity
slope stability
hydraulic conductivity
Rain
Soils
rain
Infiltration
soil
Silt
Seepage
seepage
silt
Wetting
infiltration (hydrology)
Clay
Anisotropy
clay
rainfall
infiltration

All Science Journal Classification (ASJC) codes

  • Water Science and Technology
  • Geotechnical Engineering and Engineering Geology
  • Soil Science
  • Earth-Surface Processes

Cite this

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title = "以水力耦合模式評估土壤水力傳導異向性對邊坡穩定之研究",
abstract = "In studies on the effect of rainfall infiltration on slope stability, soil hydraulic conductivity has usually been assumed to be isotropic to simplify the analysis when using a numerical model; studies have ignored the influence of anisotropic hydraulic conductivity. Therefore, this study established a coupled hydromechanical framework using transient seepage and slope stability analyses to investigate the effects of changes in hydraulic conductivity isotropy on rainfall infiltration and slope safety at various locations (i.e., at the top of the slope, on the slope, and at the toe of the slope). The results showed that when the vertical hydraulic conductivity (ky) was constant, increase in the horizontal to hydraulic conductivity (kx) (an increase in anisotropy) caused the seepage of rainfall to tend to infiltrate into the interior of the slope. This resulted in the soil on top of the slope (near the slope) and on the slope being more easily influenced by rainfall, thereby leading to soil instability. The change on the slope was the most significant. When the anisotropic ratio kr (= kx/ky) increased from 1 to 100, the wetting zones on the slopes of loam, silt, and clay deepened by 23.3{\%}, 33.3{\%}, and 50{\%}, respectively. However, increased kr led to a slower infiltration rate in the vertical direction at the toe of the slope. Comparing the results of kr = 1 and kr = 100, the thickness of the wetting zones at the toe of the slopes of loam and silt decreased by 23.3{\%} and 30.0{\%}, respectively. In the case of the clay slope, kr changes did not reach significance because of its poor permeability. Therefore, this study suggests considering the effects of soil hydraulic conductivity anisotropy when estimating slope stability, to precisely determine the effect of rainfall on slopes.",
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以水力耦合模式評估土壤水力傳導異向性對邊坡穩定之研究. / Tsai, Yi Jin; Yeh, Hsin-fu.

In: Journal of Chinese Soil and Water Conservation, Vol. 49, No. 3, 01.09.2018, p. 167-177.

Research output: Contribution to journalArticle

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