Study On The Stability And Displacement Response Of The Reservoir-Involved Debris Landslides & Its Prevention Design Under Seismic Conditions

Debris landslides, which has loose materials induced by seismic effects of earthquake is extremely hazardous. Besides, it will provide lots of loose debris for debris flow after the earthquake, which make the degree of damage much larger. Therefore, it will have a profound significance to study on the stability and displacement response of debris landslides & its optimized design under seismic conditions.Supported by the projects of National Natural Science Foundation of China-"Responding Ratio Parameter to loading & unloading and Displacement Prediction of the Debris Landslides"(Code No:40672182) and"Dynamic Parameter to Displacement vector angle and Displacement Intergrated forecast in polyphyletic information of the Debris Landslides"(Code No:40872184), and selecting Da Yaogu landslide in the Three Gorge reservoir region as the example, the thesis has carried out a study on the dynamic response of the debris landslide by means of the numerical simulation software-ABAQUS. Finally, the supporting measures of the Da Yaogu landslide is carried on optimized control. The mainly research results are as follows:1. It is found that gravity, complex water environment and earthquake dynamic factor are the major revival factors of debris landslides by analysis of the basic features and dynamic displacement features of debris landslides.2. Investigated on the geological conditions of the typical debris landslides systematically, for instance, geological settings,hydrogeological conditions, terrain features. The effects on the dynamic stability of landslide which is induced by these engineering geological conditions is analysied in detail.3. Have calculated the Fs in the case of earthquake and non-earthquake separately according to the static method which is frequently used in actual projects. It is found that the stability of the landslide is very sensitive to the seismic loading through comparing the reduced degree of Fs of the landslide.4. Numerical simulation methods and the theory of dynamic time-history analsis are used to obtain the law of dynamic response of debris landslides. In this process, the time characteristic of seismic load and the effect induced by the earthquake-induced fluctuation of water are all considered. Finally, the dynamic stability factor versus time curve has been solved by explicit finite element lumped mass integration algorithm. 5. Three different retaining control measures were selected to protect the landslide. The finally different support effects have been obtained by using numerical simulation methods, then the most reasonable retaining control measures which is used to resistant to seismic load is determined through comparing the permanent displacement, velocity amplification and the minimum safety factor under every condition.