都汶公路沿线诱发泥石流的降雨特征-《山地学报》

文章信息/Info

Title:: Triggering Rainfall Characteristics for Debris Flows along Dujiangyan-Wenchuan Highway of Sichuan

作者:: 郭晓军; 崔鹏; 马力; 孔应德; 1. 中国科学院山地灾害与地表过程重点实验室/中国科学院水利部成都山地灾害与环境研究所，四川成都 610041；
2. 中国科学院大学，北京 100049；
3. 四川省气象局，四川成都 610072

Author(s):: GUO Xiaojun; CUI Peng; MA Li; KONG Yingde; 1. Key Lab. of Mountain Hazards and Earth Surface Progress/Insti. of Mountain Hazards and Environment，CAS，Chengdu，610041，China；
2. University of Chinese Academy of Sciences，Beijing 100049，China；
3. Sichuan Meteorological Administration，Chengdu 610072，China

Keywords:: Rainfall type; rainfall intensity; antecedent rainfall; debris flow; Dujiangyan-Wenchuan Highway

摘要:: 都（江堰）汶（川）公路是通往川西北的重要交通要道，地震造成该路段泥石流危害极为严重。选择都汶公路南段为研究区，收集了2008—2011年间的22次泥石流事件及其对应的降雨过程，分析了雨型、降雨强度、前期降雨等因子对泥石流的影响，并利用I-D模型得出研究区泥石流的降雨阈值，分析时间和流域面积对阈值的影响。各种档次降雨雨型都可能诱发泥石流，降雨强度是泥石流的控制因子，降雨历时越长，需要的激发雨强越小；前期降雨对泥石流起着较为重要的作用，只有在超过14.8 mm/h时，较小的雨强才有可能诱发泥石流，且有效前期降雨越大，需要的激发雨强越小。地震造成泥石流的诱发临界降雨大幅减小，地震之后诱发泥石流的降雨条件逐年回升，2009年之后泥石流的降雨阈值较2008年大幅上升；流域面积不同，泥石流的频率也有所差异。该研究可为该区泥石流的监测预警与预测预报作贡献。

Abstract:: Dujiangyan-Wenchuan Highway is the key traffic trunk to Northwest Sichuan of China which was heavily influenced by debris flows induced by the “5·12 ”Wenchuan Earthquake. 22 debris flow events during 2008 and 2011 and their responsible rainfall processes were collected，and triggering rainfall intensity，rainfall duration，and effective antecedent rainfall was analyzed. I-D threshold was used to represent the critical rainfall conditions for debris flows. Event rainfall intensity is the key factor that triggering debris flows. Debris flow happens potentially over the condition that rainfall intensity is over 3.7 mm/h in longduration rainfall types and the critical intensity decreases as duration increases. Effective antecedent rainfall also affects the debris flow occurrences that debris flows were only possibly triggered by small rainfall intensity when the effective antecedent rainfall is over 14.8 mm/h. The lowest rainfall intensity and rainfall amount rise up annually from 2008 to 2011. I-D threshold is quite low in this region for debris flows after the earthquake，while that threshold is much higher from between 2009 and 2010，represents the effect of solid materials stability. The frequency varies according to the area of basins. The study can contribute to the debris flow warning in the study area.