Model Building And Calculation Of The Debri Flow Rate In Dam Site Of Wudongde Hydropower Station Based On PPA

Wudongde hydropower station is located in the lower reaches of Jinsha River, and its dam site is located between Wudongde village of Luquan county in Yunnan province and the reach of Jinsha River of Leijiawan village of Huidong county in Sichuan province, in the left bank of which is Huidong county of Sichuan province and in the right bank of which is Luquan county of Yunnan province. Because of little vegetation down the mountain slope, both banks of the dam area of Wudongde hydropower station have been suffering the serious soil erosion. In recent years, the debris flow with the high potential fatalness may erupt in different scales every rainy season. The reason why we have carried out the comprehensive and systematic analysis on debris flow disasters in the dam area of Wudongde hydropower station, is to effectively reduce the debris flow disaster, which has an important significance on guaranteeing the security construction, the normal operation and its synthetical benefit of Wudongde hydropower station. Meanwhile, it also has a positive and directive influence on exploring the affluent hydroelectric resource of western mountain areas and ensuring the security construction of the hydropower station in mountain areas and its operation.The flow rate of debris flow is one of the most fundamental and important parameters in the process of analyzing the debris flow disaster. Various parameters that can cause severe disasters are closely linked with the flow rate, such as the flux of debris flow, the force of impact and so on, while the flow rate of debris flow cannot be directly obtained by means of field survey (only few domestic observation station of debris flow have the advantage to actually measure the flow rate of debris flow.). Therefore, how to accurately work out the flow rate of debris flow according to the previous survey information? This question is very important to prevent and forecast debris flow disasters.The thesis starts with materials of solid accretion of debris flow by the field investigation and adopts the inverting way. Based on the pulled particle analysis of debris flow (PPA), the computation model of the flow rate of debris flow has been built according to the research of the initiative condition of solid accretion of debris flow. And the thesis has verified the model by means of the actually measured data of Jiangjiagou observation station and the result from verifications is generally good. At last, combining with the situation of field survey, the thesis has calculated the flow rate of debris flow in the dam area of Wudongde hydropower station by adopting the computational formula of the flow rate of debris flow of Tie'eryuan in southwest area and the computational model of the flow rate of debris flow of PPA. The main research contents are as follows:A. Analysis on the development conditions. On the basis of the abundant theoretical research from home and abroad and combined with local data information and the result of field investigation, the thesis analyzes the integral development conditions of debris flow in the dam area of Wudongde hydropower station.B. Obtaining geometric parameters by means of GIS, RS and GPS (3S). First of all, the thesis interprets the picture of RS using GIS software indoors, and surveys every debris flow gully by holding GPS equipment outdoors, to obtain the accurate geometric parameters of debris flow.C. Analysis on cumulate particles. The thesis analyzes on solid particles by adopting the sieving analysis outdoors and the sink speed method indoors.D. Investigating the influencing factors to the flow rate. There are numerous influencing factors to the flow rate of debris flow. Combining with the situation of field investigation of every debris flow gully and the microstructure research and the composition testing of solid particles, the thesis analyzes the influence of the following aspects to the flow rate of debris flow:slope of the main gully, conditions of circulation area, amount and composition of solid particles.E. Qualitative estimation of dynamic characteristics of debris flow. On the basis of analysis on accretion particles of every debris flow gully and combining with specific influencing factors to every gully, twenty-seven debris flow gullies investigated on the spot will be divided into five types.F. Judging the characteristics of debris flow fluid. The thesis, first of all, confirms the unit weight of every debris flow fluid in reservoir region by means of normative approach, adopting the relationship between the accretion and the unit weight of debris flow. And then the unit weight of debris flow slurry of every gully in reservoir region will be determined by using the relationship between the unit weight of debris flow fluid and the concentration of debris flow slurry.G. Confirming the diameter of pulled particles. On the basis of the drawn graph of cumulative probability of particles in every gully and adopting Moss'sorting method, the interval of the diameter of particles has been roughly determined. And combining with the investigated situation of the profile of accumulation area of debris flow outdoors, the thesis comprehensively confirms the marked diameter of particle of pulled particles to calculate the flow rate of debris flow.H. Building the model. In view of PPA, the thesis analyzes the force which acts on the bodies of motionless solid particles at the bottom of channel-typed debris flow and makes the computation model of the flow rate of debris flow. The thesis also confirms the coefficient of the model and verifies the model by using the actually measured data of Jiangjiagou observation station in Dongchuan. At last, it calculates the flow rate of every debris flow in the dam area of Wudongde hydropower station, which would be compared with the computational formula of the flow rate of debris flow of Tie'eryuan in southwest area.