Research On The Development Characteristics And Control Engineering Measures Of Wenjiagou Debris Flows After The Earthquake In Qingping Township Of Mianzhu City

At14:28on May12,2008, magnitude8.0strong earthquake occurred in Wenchuan County, Sichuan Province. The meizoseismal area of Wenjiagou debris flow had such characteristics as synchronization, high frequency and simultaneous occurrence, which become the biggest impact characteristics of debris flow activity.The paper, using Wenjiagou debris flow after the earthquake as the research object, study,in detail, the development background, forming conditions, debris flow zoning, active characteristics, and dynamic features, and based on the mechanism of this debris flow to put forward the prevention and control measures of Wenjiagou debris flow. The paper mainly for understanding and the conclusions are as follows:(1) Wenjiagou before "5.12" earthquake was not a debris flow gully, causing the giant high-speed remote-debris flow landslide in the earthquake,which provides a rich source of solid content for the development of debris flow.(2) Trough the analysis of the main gully with branch trenches, the shape of the material sources and the quantity material sources show that the gully formation after geographic and geomorphic conditions and content source conditions.(3) After the "5.12" Wenchuan earthquake, Wenjiagou debris flow outbreaks so much, and each occurrence of debris flows are high-intensity rainfall in the region closely.Studies have shown that the formation of the critical earthquake debris flow rainfall significantly reduced.Wenjiagou debris flow in the development phase, activity frequently, are high-frequency debris flow, the future until both sides of the trench and slope deposits on the slope stability and debris flow activity to stabilize.(4) Reference Liu Xilin-Karagawa model of debris flow deposits on Wenjiagou "9.24","8.13","8.19" and "9.18" four times to evaluate the scope of the accumulation of debris, but the accumulation of evaluation results and the actual difference is relatively large; so, increase the seismic reference model correction coefficient K for the establishment of the correct model for different frequency ranges Wenjiagou to predict the risk of landslides, debris flows in the model for the earthquake risk provide a basis for the forecast range.(5) Through the analysis of Wenjiagou Debris flow conditions, valleys activity characteristics and the dynamic characteristic, this paper use Wenjiagou Debris flow prevention and treatment programs are based, and to take soil and Landang governance. For Wenjiagou "8.13" Debris flow prevention project using the general idea is:"Water sand separation, solid barricade to stop, monitor maintenance."(6) Rainfall in in flood season in2011before the completion of the project management of construction of the main, from May1to August31so far, there are10times more than50mm of rainfall in rainfall, maximum rainfall of a single180mm, hour maximum rainfall intensity for the54.5mm/h. Automatic rain gauges to monitor the total rainfall is1223.5mm. Upper, middle and lower reaches of engineering measures have played a proper construction of basic effects, the overall project performance and stability, ensure the Qingping Township residents downstream lives and property.