Reliability analysis of reservoir landslides in multi-slip zones considering spatial variability and seepage field fluctuation

Rainfall and reservoir water level fluctuations are recognized as primary triggers of landslide instability in conventional reservoir landslide stability and reliability analyses. However, deterministic methods that treat landslides as homogeneous masses disregard the inherent spatial variability in soil parameters, resulting in inaccurate calculations of landslide failure probabilities. This study investigates the Taping landslide, a multi-slip zone landslide in the Three Gorges Reservoir area. The landslide stability is evaluated using a deterministic analysis method under rainfall and reservoir water level fluctuation conditions. Subsequently, the unsaturated seepage analysis result is incorporated into a random finite difference method computational framework that considers soil spatial variability to assess the landslide reliability. The probabilistic analysis method is employed to examine the impact of spatial variability in soil parameters on the reliability of the reservoir landslide. The results show that landslide stability and reliability are negatively affected by spatial variability of geotechnical parameter. Furthermore, the coefficient of variation, correlation coefficient, and scales of fluctuation for soil shear strength parameters adversely affect the stability and reliability of the landslide to varying degrees. The study results contribute to the assessment of the probability of failure and the implementation of mitigation and prevention measures for the Taping landslide.