Study On The Characteristic And Occurrence Mechanism Of Niujuangou High-Speed Landslide

The earthquake occurred in 12th May 2008 induced more than 15000 landslides, more than 300 are large-scale landslides. The Niujuangou Landslide is one of them. It has large size, and the features different from those of the usual gravity environment geological disasters. These features include unusual vibration destruction, deformation instability mechanism, causing ground vibration, strong dynamic characteristic, high-speed projectile in large scale and remote motion etc.The thesis, based on the research in the characteristic slip of Niujuangou high-speed landslide, puts forward the formation mechanism of high-speed motion caused by Niujuangou high-speed landslide under the circumstance of strong vibration. The thesis indicates that the formation of high-speed motion is related to the process of the broken locked patches.The locked patches are the special zone between landslide mass and high strength of the landslide bed (it is similarly to the locked patches with stress concentration in seismogenic fault). In the process of the broken locked patches inducing ground vibration is called seismic landslide which is considered as an important mechanism for sudden initiation of the Niujuangou landslide. The focus of seismic landslide is between slip mass and slip bed, it has direct effect on the start style and accelerated velocity of the slip mass, therefore,it is the essential cause of sudden initiation.It is hereby think that the generation of seismic landslide is the formation mechanism of Niujuangou landslide and is also the prerequisite of the high-speed cast of slip mass.(1)The thesis, using the means of M.wyss and catastrophe theory, estimates the earthquake magnitude of landslide earthquake and the energy released from the earthquake and analyze the whole process of locked patches from breaking to vibrating, in fact analyzing the muzzle velocity and accelerate velocity causes by landslide earthquake.(2)The thesis, through numerical simulation software simulating the landslide setout process, analyzes the effects on slope motion after the landslide vibration.(3)In this thesis, through model test the relationship between landslide energy and locked patch of Niujuangou landslide is got by studying the sudden initiation phenomena in shearing moment of locked patches with different diameters.There are not much research in landslide earthquake both in China and abroad especially the research on the mechanism of landslide vibration causing high-speed landslide. Nowadays, no systematical theory in the world can explain the occurrence of high-speed landslide. The thesis, based on the, puts forwards the new interpretation about the high-speed acute landslide, provides new methods for the research on large scale high-speed earthquake landslide and guidance on geological disaster prevention.