Analysis and discussion on the stability of Jinjiang Landslide under the operating conditions of earthquake

The limit equilibrium method from mimetic statics numeric method, a recommended method in current specifications, is adapted at present in most calculations to the stability of landslide. To most permanent and transient operating conditions in landslides, the result calculated with this method is in accordance with the result evaluated by geologic theory; but to the operating conditions in earthquakes, most results are quite different with each other. The Jinjiang landslide is a giant one near the dam of the Baihetan power plant. In the calculations to the slide with limit equilibrium method, 3 steps are adopted in the study. Firstly, based on the calculation ways for anti-seismic stability of the earth-rock dam specified by “The Seismic Design of Hydraulic Structure DL 5073-2000”, values such as the dynamic distribution coefficients at different heights and the horizontal seismic force component and the dynamic distribution coefficient at the corresponding heights are figured out by means of the handling method to earthquake effect. Secondly, the horizontal acceleration value of the earthquake force that acting on the whole landslide mass is solved. Lastly, the stability calculation is done with the horizontal acceleration value. The results prove that, under seismic operating conditions, the Jinjiang slide is stable as a whole with the stability coefficient being1.23~1.45, which is not only quite in accordance with the results by geologic analysis, but also avoids the discrepancy between the mimetic statics numeric method calculating results and practical geologic analysis results.