The Debris Flow Assessment Method Based On Fuzzy-AHP Method And Its Appication

Debris flow hazard is one of the major geo-hazards which often happen in themountaineous areas, with the characteristics of recurrency, burstiness, massiveness, simultaneousness and transmit performance. It can destroy houses, factories, all kinds of transport facilities, block river, drown people and livestock, destroying the land even cause village crash disaster. It’s devastating. In recent years, the frequency is high, especially after the Wenchuan earthquake, the ecological environment of the quake zone sufferedsevere damage. The earthquake gave birth to numerous landslides, avalanches, andpotentially unstable slopes of poor geological conditions, and provide favorable conditions for the occurrence of debris flow, withthreatening life and property safety of the mountain people.In order to prevent and control of debris flows and governance effectively, scientific research on the debris flow hazard evaluation is undoubtedly important theoretical andpractical significance. But in past theoretical studies, scholars do more research on description of the geographic and qualitative analysis of concept.In quantitative analysisand prediction of the risk assessment, we have not obtained satifactory results.Basedon the above, with selecting nine quantitative risk factors; the evaluation model of Fuzzy-AHP is established. Finally, the debris flow is analyzed in quantitative and evaluated.The main work and achievements include：(1) Debris flow characteristics, classification, occurrence conditions, influence factors are discussed. At the same time, on the debris flow risk assessment methods andsome new mixed evaluation methods were summarized, and pointed out their advantages and disadvantages, the final choice of fuzzy hierarchy comprehensive evaluationmethod is applied to the assessment of debris flow gully.(2) Choose a one-time debris flow(possibly) the maximum out of the amount ofdebris flow frequency,lithology grades, drainage area, main gully average slope basin,maximum relative height difference,24h maximum rainfall, vegetation cover within th e watershed, population density. Nine risk assessment factors used in this article in the evaluation model.(3) According to the basic principle of Fuzzy-AHP method, this paper establishsthe risk evaluation model of debris flow gully and uses this model to the mill ditchgully of risk evaluation, the evaluation results and Professor Liu Xilin recommended risk degree calculation formula is obtained for the risk evaluation result and the valleyhistorical data were compared. The method in debris-flow risk assessment is feasible.(4) The establishment of evaluation model on Guangdong Qingyuan flying Temple debris flow hazard analysis is carried on and the valley of the risk grade division,finally proposed in view of the Qingyuan flying Temple debris flow prevention measures.