Global sensitivity analysis for evaluation of water level fluctuation of anchored and non-anchored slope on reservoir bank

Water-level fluctuation (WLF) caused by rainfall or reservoir operation has an impact on the long-term stability of reservoir bank soil slopes because it changes the equilibrium of surface and groundwater levels. Thus, determining the link between groundwater level and surface water level, as well as the association between WLF parameters and other parameters, is critical for slope stability control measures execution. This research identifies essential factors for anchored and non-anchored slope on reservoir bank under WLF using a variance-based global sensitivity analysis (SA) method while accounting for multiple parameters and scenarios. This investigation involves two types of soil slopes: sand and clay. It consists of more than 10 parameters divided into three categories: geological characteristics, WLF, and anchoring parameters. WLFs are the most sensitive contributors to slope stability in sand and clay slopes. Furthermore, the surface water level parameter is more sensitive than the groundwater level parameter, with total-order Sobol' indices of 0.48 and 0.28, respectively. After the anchors are installed on the slope, the sensitivity indices of slope inclination and angle of failure surface rose dramatically, increasing by 0.11 and 0.24, respectively. The findings of the first-order indices show that surface water level and groundwater level have opposing tendencies, which is a significant inducement to cause a soil landslide on the reservoir bank. This study investigates the sensitivity of sand and clay soil slope parameters to changes in water level, as well as the interaction mechanism between its primary control elements.