Effects of the Rainfall-Triggered Lisse Effect on the Stability of Loess Slopes.

This paper coupled a water-air two-phase hydrodynamic (WATPH) model with the Iverson's method to analyze the influence of the Lisse effect on the fast groundwater pressure (Pw) response and the slope stability. Furthermore, the sensitivities of the driving force and loess soil parameters were investigated. Results showed that the WATPH model simulated the height and rise of the depth to the water table reasonably well. The depth to water table before rainfall (H0) had a significant impact on the Lisse effect and the slope stability. When the H0 was less than approximately 1 m, the rainfall triggered a significant Lisse effect and decreased the slope factor of safety (Fs). When the rainfall intensity (Ri) was higher than the saturated hydraulic conductivity (Ks), the Lisse effect and the Fs slightly changed with the increase of the Ri, and the slope tended to be unstable with continuous rainfall. With increasing Ks, the Lisse effect noticeably increased, and the minimum Fs quickly decreases. The analysis of the normalized sensitivity coefficient revealed that H0 had a dramatic impact on the Lisse effect and loess slope stability. The different Ri and Ks values had prominent influences on the Lisse effect and slight impacts on Fs. [ABSTRACT FROM AUTHOR]