Studies On The Origin Cause Of Formation And Law Of Development And Evolvement Of Debris Flow Of Qiongshan Ditch Of Danba County

As the development of people's societal and economic activity, people excessive exploit natural resources and the environment was destroyed continuously. These cause the natural disasters such as the debris flow become more serious. Therefore the study, evaluation, forecast and mitigation management of the debris flow must be strengthened, economical and effective preventing engineering must be enforced. Only by this way the occurrence of the disaster can be prevented and the damage of the disaster can be reduced.The thesis analyses the circumstances of the debris flow happened in Qiongshan ditch of Danba county of Sichuan province, studies the rainfall debris flow and analyses it's origin cause of formation and the law of development and evolvement. The thesis also systematically predicts and evaluates the risk of this type debris flow. According to the result of prediction and evaluation, put forward a preventing and curing scheme aimed at this area.First, analyses the character of the debris flow happened and obtains the primary character. Second, according to the three basic factors, rich solid material resource, essential terrain and enough hydrodynamic, systematically predict this type debris flow including occurrence moment, scale and danger degree of disaster which might take place in future. The analysis on topographical condition adopts the valley vertical section shape index N value of the ditch , ultra entropy 8 xp of basin system to predict. Adopt the analytic approach of the amount of source to solid material conditions. Adopt coefficient of module ratio and maximum entropy spectra analysis to carry on analysis to the cycle of water motive force condition, and predict with grey model. Predict the scale of debris flow which might take place in future by experiential method being based upon analysis to the debris flow happened. After confirming the dangerous area, forecast the fatalness of debris flow according to the model of evaluating a single ditch. Third, evaluate the risk of the disaster the debris flow brought. Confirm evaluation area on danger area basis, then evaluate the fatalness, damageability, loss of the debris flow. Finally, combining with foregoing research, put forward an economical and effective preventing and curing scheme for the debris flow happened in Qiongshan ditch, moreover, evaluate the project's benefit.