Stability Analysis of Unsaturated Soil Slope by Coupled Hydro-mechanical Model Considering Air Flow

공기흐름을 고려한 수리-역학적 연동모델에 의한 불포화 토사사면의 안정해석

Cho, Sung-Eun

  • Received : 2015.09.29
  • Accepted : 2016.01.12
  • Published : 2016.01.31


Stability analysis based on the limit equilibrium method combined with the result of infiltration analysis is commonly used to evaluate the effect of rainfall infiltration on the slope stability. Soil is a three-phase mixture composed of solid particle, water and air. Therefore, a fully coupled mixture theories of stress-deformation behavior and the flow of water and air should be used to accurately analyze the process of rainfall infiltration through soil slope. The purpose of this study is to study the effect of interaction of air and water flow on the mechanical stability of slope. In this study, stability analyses based on the coupled hydro-mechanical model of three-phases were conducted for slope of weathered granite soil widespread in Korea. During the process of hydro-mechanical analysis strength reduction technique was applied to evaluate the effect of rainfall infiltration on the slope stability. The results showed an increase of air pressure during infiltration because rain water continuously displaced the air in the unsaturated zone. Such water-air interaction in the pore space of soil affects the stress-deformation behavior of slope. Therefore, the results from the three-phase model showed different behavior from the solid-water model that ignores the transport effect of air in the pores.


Slope stability;Coupled hydro-mechanical analysis;Rainfall infiltration;Strength reduction method;Air flow


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Supported by : 한국연구재단, 국토교통과학기술진흥원