Analysis On Cause Mechanism And Stability Of Gangjian Landslide Of Kala Hydropower Station In Yalongjiang River

The gangjian landslide is located in the middle of the upper bank and the lower bank of kala hydropower station, which is 1.316km away from the upper bank and is 2.797km away from the lower bank. It is a very huge landslide with nearly 67m average thickness and about 8846.40×10~4m~3 of accumulation. If the landslide slides to the river rapidly, it will cause tremendous slope surge to destroy the dam. So that, evaluating the stability of the landslide and forecasting its danger are also particularly important to assess the possibility of the project.This paper uses many methods integratively to study the gangjian landslide, such as geological—historical analysis, limiting equilibrium and numerical analysis. By analyzing the physical geographical condition and geological background of the investigated area, this paper researches the basic features and genetic mechanism about the landslide, and evaluates sensitivity factors and the current stability as well as development tendency about the landslide's stability. Based on these, recurring to experienced formula and correlated theory, this paper forecasts the events about landslide damming of river and surge caused by the slope failure, furthermore, evaluates the harmfulness.The gangjian landslide's mechanism of deformation failure is a representative Sliding—Bending Mode of the consequent slope. The results calculated by the methods of geological—historical analysis, limiting equilibrium and numerical analysis are as same as each other. They all show that the whole stability of the landslide is very well, and indicate that the accumulation in the first—part of the landslide would not glide while as reservoir and earthquake. The result of the research of the landslide surge indicates that the failure of the part of the landslide will arise a surge only height to less than lm, which will not destroy the important buildings in the lower dam. Based on the calculation, the accumulation of the first-part of the landslide which would slide into the river is only 55,200 m~3, it will influence the effective capacity very little, and it will not endanger the important buildings in the middle dam.