Basic characteristics and deformation mechanism of Zhoujiagou landslide in Three Gorges Reservoir area

Abstract

[Objective] The impact of reservoir water level fluctuations and rainfall on the cumulative displacement monitoring curves of water-related soil landslides in the Three Gorges Reservoir area is investigated, with a focus on periodic abrupt changes. Enhanced accuracy in landslide disaster warnings and improved effectiveness of prevention and control measures are deemed essential to prevent misjudgments in deformation stages and to address early warning failures caused by abrupt deformations. [Methods] The Zhoujiagou landslide, located in the Tongzhuang River Basin, is examined through the integration of reservoir water level and rainfall data, supported by monitoring records and field investigations. The finite element software Geo-Studio is utilized to compute seepage fields, displacement fields, and stability under actual conditions, with the objective of analyzing deformation characteristics and instability mechanisms. [Results] From April 2022 to April 2024, four abrupt deformation events were observed in the cumulative displacement monitoring curve of the Zhoujiagou landslide, closely correlated with heavy rainfall(daily rainfall exceeding 35.6 mm) and accompanied by a distinct lag effect. At reservoir water levels above 160 meters, inward-directed dynamic water pressure was found to enhance slope stability, raising the rainfall threshold to 40 mm. [Conclusion] The stability of the Zhoujiagou landslide is significantly affected by reservoir water level fluctuations and rainfall infiltration, with rainfall identified as the primary trigger for deformation. These insights provide valuable scientific guidance for the monitoring, early warning, and prevention of similar landslides in the Three Gorges Reservoir area.

Keywords

deformation mechanism / stability analysis / numerical simulation / rainfall / reservoir water level / landslide / deformation / Three Gorges Reservoir