极端水力条件下三峡库区藕塘滑坡灾变过程物质点法模拟OA

[Objective]Reservoir bank landslides are triggered by multiple factors,and their disaster evolution process and dynamic response characteristics exhibit significant nonlinearity and spatiotemporal heterogeneity.To achieve effective prevention and control of reservoir bank landslides,it is essential to elucidate the influence of the coupled action of rainfall infiltration and rapid reservoir water level drawdown under extreme conditions on the landslide evolution mechanisms and dynamic response patterns of landslides.[Methods]This study employed the material point method(MPM)to construct a two-dimensional numerical model of the Outang landslide in the Three Gorges Reservoir area,and simulated its initiation and acceleration processes under the combined action of rainfall and reservoir water level fluctuations.By analyzing the deformation and stability of different parts of the Outang landslide under different hydraulic conditions,this study revealed the evolutionary characteristics and instability mechanisms of the landslide.[Results]The results showed that:① The stability of the Outang landslide was jointly controlled by rainfall and reservoir water level fluctuations.Reservoir water level drawdown mainly affected the primary sliding mass at the toe,while rainfall had the most significant impact on the stability of the tertiary sliding mass at the crest.This finding was highly consistent with monitoring data.② Under the combined action of rainfall and water level fluctuations,localized collapse occurred at the toe and overall sliding occurred at the crest of the Outang landslide,and no obvious signs of instability were observed in the middle part.③ Under extreme conditions of rapid water level drawdown and intense rainfall,significant sliding occurred only at the toe and crest,and the probability of overall sliding of the landslide mass along the bedrock interface was low.④ During the failure initiation stage of the landslide mass,significant differences were observed between the distributions of initial strain and initial displacement along the main sliding direction,and this should be considered when arranging monitoring points.[Conclusion]Based on large-deformation numerical simulation,this study analyzes the main controlling factors of the long-term stability of giant paleo-landslides along reservoir banks,providing a theoretical basis for the early warning and prevention of such landslides.