Academic literature on the topic 'Lao wu chu kou'

碩士
國立暨南國際大學
土木工程學系
104
It has been a long time that debris flows occurs in Taiwan. But the predilection of debris flows is mainly affected by the terrain and the rock materials. What’s more, the rock materials are also different which affected by the geological location of catchments and the rock types, and then bring out the differneces of the kinetic energy conditions of the debris flows’ occurences. First, to classified the rock types of the small catchment of Chuo-shui river, Wu river and Gaoping river basins, and aggregated the three physiographic factors, including: topographic factors (relative height, channel-bed slope and slope ratio), the flow factors (watershed area, the mainstream length, form coefficient and drainage density), material factosrs (hypsometric curve, landslide areas before and after typhoon events and the ratio of landslide areas before and after typhoon events), as well as rain-induced factor (RTI value) and other factors. Establishing to form the full factorial determination modes of debis flows from the datas of Typhoon Toraji event by logic regression formula, then verifing the justification of the modes by Typhoon Mindulle event. The second step of factor correlation analysis is to identify independent factors, and to explore the characteristics of the independent factors in the different rock f partition. To select independent factors in three physiographic factors in different rock partitions, and to add the hydrological factors into logical regression formula, then model the debris flow determination mode of characteristic factors. At the last, to analyze the debris flow determination modes of the full factorial factors and features factors. According the analysis, the correlation coefficient between the ratio of channel-bed slope factor and watershed area factor is the lowest in the sedimentary district, and the others are all higher. And the correlation coefficient between the slope ratio and other physiographic factors is the lowest in the slate district. Therefore, 4 factors considering the channel-bed slope, watershed area, landslide areas before typhoon events and RTI value as the features factors in the sedimentary district. 8 factors considering except the relative height and channel-bed slope in the slate district. According the final result, the full factors and characteristic factors of the debris flow determination mode are medium consistent in the sedimentary district, the accuracy is more than 87.4%. And the full factors and characteristic factors of the debris flow determination mode are almost exclusively consistent in the slate district, the accuracy is also more than 96%. The differences of physiographic factors characteristics between the two different rock types affect the accuracy of the debris flow determination mode. So the author recommended to consider the necessary to study the different rock types. Finally, this research used the datas of the three basins to establish a common debris flow determination mode by logical regression formula, and it showed that the common debris flow determination mode is provied with high-accuracy prediction. Then setting the threshold of the subsequent occurrence and assuming the maximum intensity of rainfall, to establish the alert accumulated rainfall of the small catchment by the accumulated rainfall values.