Study on reactivation mechanism and ductile deformation of Sanmendong Landslide in Three Gorges Reservoir area
The impoundment of the Three Gorges Reservoir triggers a large number of reactivated and deformed ancient land-slides along the reservoir banks.The concept of"ductile deformation"is introduced to explain the differential deformation re-sponse of ancient landslides under similar influencing factors.Taking the Sanmendong Landslide in the Three Gorges Reservoir ar-ea as an example,we analyzes the deformation characteristics and the mechanism of"ductile deformation"during the reactivation process based on field geological investigations and 17 a of monitoring data.The research findings indicate that:① The Sanmen-dong Landslide is a gentle ancient sedimentary landslide that is reactivated and deformed after the impounding of the Three Gorges Reservoir.The main deformation features at the front,middle,and rear parts of the landslide are bank collapse,tensile cracks or slumping,and tensile-shear cracks respectively.② During the falling stage of reservoir water level,the landslide deformation is sensitive to rapid water level decrease.When the reservoir operates at low water levels and during the water rising periods,rainfall especially continuous heavy rainfall is the main triggering factor of landslide deformation,resulting in sustained deformation.③During the occurrence of"ductile deformation",the internal part of the landslide undergoes a process of compaction,leading to in-creased soil density and enhanced cohesion,thus improving the shear resistance of the soil and providing the strength to resist sub-sequent deformations for a certain period.The research results can provide a reference for landslide monitoring and early warning in Three Gorges Reservoir area.
ancient landslidereactivation mechanismductile deformationSanmendong LandslideThree Gorges Reservoir area
国家科技期刊平台
NSTL
万方数据
维普
