| The study area Hongchun basin is located in the northeast side of Yingxiu Town,which is the 2008.5.12 Wenchuan earthquake epicenter,It is also located on the left bank of the Minjiang River,the ditch and valley pattern is approximate a sector and its area is 5.35km2.The highest point is located in Xin Dian Zi Gou's source,the elevation is 2162.2m;Mizoguchi and Minjiang River inter-section height is 881 m,relative elevation is 1288.2m,channel longitudinal is 3.6km,average longitu-dinal gradient of gully is 357.8 per thousand.Because the Hongchun gully is located near the epicenter,after Wenchuan earthquake,accelerating the development of geological disasters,the development of a large number of landslide and collapse geological disasters within the basin,a large number of loose material in the basin,the present situation of geological environment is fragile,after the earthquake seven years ago,a total of 5 debris flow and multiple flood,including 1 large debris flow occurred in the Hongchun gully disaster prevention engineering construction before August 14,2010,Debris flow treatment project to be completed by the end of June 2011,Gully Hongchun debris flow control works completed by the end of 6 2011,After the projcet completion to today,Hongchun gully occurs 2 times medium debris flow,2 times small debris flow and many times flood,Debris flow geological hazards are very active,the frequency and scale of the outbreak were significantly increased before the earthquake,potential hazards of debris flow hazards.At present,the amount of the remaining material source in the Hongchun gully basin is very huge,the possibility of renewed large-scale debris flow is still large,by numerical simulation over the past few years comparative hydrological occurrence of debris flow,analysis of disaster prevention and reduction effect of the disaster prevention engineering,to protection of national highway G213,Duwen highway and Yingxiu town's life and property safety has important scientific value and practical significance,it can provide advanced prevention and control effect prediction and technical reference for other engineering design scheme of debris flow,also has a good economic and social benefits.This article has done a lot of work,the main results and conclusions is following :(1)on the base of analyzing the disaster mechanism of "8.14" in Hongchun gully on debris flow,expounds the design principle of Hongchun gully control project,can provide a good reference and reference value for the prevention of other debris flow.The earthquake zone of debris flow and start a concentrated outbreak of provenance is closely related to the,the earthquake source is mainly concentrated on the launch slot,blockage,propose three ways.Hongchun gully of debris flow disaster in the process of the groove in the domain H05 landslide source is concentrated to slope slot start;The solid material of H05 landslide kerve start accumulation in the landslide near the lower bend lake formed plugging point,the concentration caused by Gan Xi Pu Gou lower channel source lake outburst after the start;Gan Xi Pu Gou source block of solid material collapse and formation in the main channel and the formation near the confluence of two blocks and burst,the confluence of the Gan Xi Pu Gou again caused by channel on the.The alternating start pull trough,blocking the collapse,propose three kinds of source,superposition amplification,eventually lead to catastrophic outbreaks of debris flow.According to the above mechanism,in the design of disaster prevention engineering,on the basis of the upper solid source of anti blocking,reducing potential in regulation,downstream bed drainage principle,reasonable design of the existing control scheme.(2)This article uses the ArcGIS,Flo-2D and other software,the Hongchun gully debris flow with disaster prevention engineering as the research object,Repeated investigation and experiment in the field,using related data,through the high precision remote sensing data interpretation,to find out the characteristics of gully Hongchun debris flow channel,the distribution of material source,the layout and design parameters of the treatment project,a comprehensive analysis of the characteristics of the debris flow and the distribution of space position in the condition of engineering management,at the same time,a variety of factors related to the outbreak of debris flow were extracted and analyzed,spatial analysis function and high precision DEM data through GIS,division of Hongchun gully sub unit of debris flow catchment,then in each segment catchment as an evaluation criterion,with each control project layout conditions of the study area,to establish the evaluation model of the effect of debris flow control project in the study area,then the simulation results are obtained and combined with the monitoring data for analysis and research.(3)It was found in the study that after the Hongchun gully disaster prevention project completed,it have broken twice debris flow in the de-sign condition and once debris flow exceeded the design condition.In order to reasonably judge the effect of the project,we compared the simulation results with the actual operation results of the project,so the numerical simulation in this article,Select 2 representative recurrence periods of frequencies(p=2%,p=1%)to simulate.At the same time,according to the monitoring data of different sections and by setting up reasonable water gathering point positions in the simulation process,the disaster prevention project is divided into several sections for numerical simulation in this article.The numerical simulation results show that,in the design condition(p=2%)the Hongchun gully disaster prevention engineering effect is remarkable,and over the design condition(p=1%)the effect is also good. |
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