The Basic Characteristics And Occurrence Mechanism Of Extra Large Viscous Debris In Donyuege Of Nu River

Dongyuege gully is located in the east of Gongshan County, Nu River autonomous prefecture, Yunnan province.The Basin has wide coverage of loose material, and vegetation is very well developed. In recent years, the landslide and debris flow disaster occurs every year, but which can really transport to Mizoguchi and cause great disaster of large debris flow does not see more. On August 18,2010, this basin experienced the outbreak of the large debris flow under the ice and snow meltwater and short-term rainfall, which destroyed a large number of houses located in Mizoguchi, resulting in huge casualties and property losses. It was one of the typical large viscous debris flows and a rare and huge highway geological disasters. To study the starting movement characteristics and mechanism of this kind of strong regional debris flow as well as provide more accurate feasible basis for the debris flow prevention and early warning system, so I did detailed field investigation on the Dongyuege the debris flow and indoor and outdoor test research, and I obtained the following conclusions:(1) The whole process of the debris flow lasted for nearly half an hour, there was a number of blockage in the ditch, the formation of nearly 13 flows. In particular, a generous amount of jam is located in the about 500m upper reaches of the formation of Mizoguchi, extent promotes the the debris flow rapidly spewing out, flooding the iron ore plant, entire cottage and farmland on the Mizoguchi and cause blockage of the Nu River, return water up to 10 meters, destroyed 15 cottage on the both side of ditch, Caused 92 people to die.(2) The generous amount of loose rock body accumulation after years in the Dongyuege ditch is the occurrence of debris flow disaster in the required source conditions. "V" type narrow funnel shaped gully form can not only promote the formation of material source and water conditions, but also provide plenty of power conditions in the running process of the debris flow. The rich vegetation in the debris flow after the start, not only as a part of the debris flow fluid itself to expand the scale of debris flow and debris flow in the source area of a large number of loose accumulation of the formation of a larger role in promoting.(3) Through field investigation of Dongyuege ditch the debris flow related parameters, combined with relevant specification and empirical formula, the bulk density velocity, flow and pressure of debris flow gully Dongyuege are calculated, and determined Nujiang 8.18 Dongyue the debris flow as determine for the large-viscous-low frequency gully type rainstorm-snowmelt debris flow.(4) Based on the Beckman Coulter IS 13320 laser diffraction particle size analyzer, combined with field field particle size test, the relative particle size curves were drawn. Combined with a diameter of value analysis method, using Fokker and ward the granularity parameter formula, mean to the granularity, sorting coefficient, skewness and kurtosis parameters of the Dongyuege gully for calculation and analysis.