Physical model test of the deformation mechanism of the multi-sliding zones landslide subjected to the operated reservoir

Many large landslides in reservoir areas have been recognized as the presence of multi-sliding zones owing to the distinctive deformation characteristics. Due to water-level fluctuations, the deformation mechanism of the multi-sliding zones landslide is poorly understood. Herein, a simplified model of a multi-sliding zones landslide subjected to the operation reservoir was conducted to reproduce the deformation process and obtain the deformation characteristics, pore water pressure, and earth pressure to investigate the deformation mechanism. The results suggest that the deformation exhibited by the multi-sliding zones landslide subjected to the operated reservoir take on a regional deformation characteristic with the multi-sliding zones as the boundary and correspond to the abrupt change in earth pressure and pore water pressure. According to the effective stress principle, the deformation mechanism is investigated by relying on the response relationship between effective stress and deformation. It shows that the softening effect caused by initial water infiltration, outward seepage force caused by initial water-level drawdown and the driving force are the external factors triggering the regional deformation of the multi-sliding zones landslide, while the immediate cause of the regional deformation is the rapid change in effective stress, which combined with the decreasing trend before the rapid effective stress release, is crucial for accurately assess whether the multi-sliding zones landslide is about to deform. This research provides improved insight into the deformation mechanism of the multi-sliding zones landslide.