Instability of partially saturated soil slopes due to alteration of rainfall pattern

Abstract The influence of climate change on rainfall patterns has the potential to alter stability of partially saturated soil slopes. Changes in rainfall patterns have a strong influence on stability of partially saturated soil slopes, which recently have resulted in shallow landslides. In this paper, slope stability is assessed using a monolithically-coupled finite element model for a deformable partially saturated soil subjected to surface infiltration of water. Numerical analysis solves for the matric suction distribution over a two-dimensional cross-section of a soil slope while varying permeability, and considering a surface layer of soil with different permeability. The formulation of hydraulic conductivity for a coupled analysis includes dependence on porosity and degree of saturation to illustrate the effects of water infiltration and deformation behavior in partially saturated soils. Numerical examples demonstrate that change in rainfall patterns may trigger slope instability earlier in the rainfall event than for rainfall events of the past. Assessment of these simulations can provide an indication of the potential influence of climate change on shallow landslides in many mountainous areas in South Korea.

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