摘要
泥石流的降雨预警指标常常选用前期有效降雨量和激发雨强进行评价,而前期有效降雨的关键在于确定前期降雨影响天数和日降雨衰减系数。福建山区每年发生的泥石流众多且危害大。本文结合福建山区降雨特点,总结了前期有效降雨量确定方法以及福建区域的泥石流概况,通过对比历史数据8 d及14 d前期降雨量,确定了8 d作为前期有效降雨量影响时间;通过引入格拉布斯准则剔除异常数据和利用凸包算法寻找散点数据的外边界,建立了前期有效降雨量与1 h激发雨量的幂指数关系;最后根据福建地区的泥石流发育特征,分析了泥石流降雨阈值预测模型的影响因素及未来改进方向。结果表明福建省泥石流类型主要为坡面型泥石流,且利用前期有效降雨量和短历时强降雨量建立的阈值模型f(h_(60),Re)=h_(60)-38.93Re^(-0.12)(h_(60)为小时降雨量;Re为前期有效降雨量)在泥石流启动方面获得较好的预测效果;单沟泥石流的启动除了降雨外还与下垫面的地形和物源量存在一定的联系。本研究可为福建地区多植被覆盖区泥石流的降雨阈值模型提供一种改进方法与思路。
Precedent effective precipitation and critical rainfall intensity are usually selected to constitute the early warning index of debris flow.An imperative approach to settle precedent effective precipitation is to inquire the number of days affected by precedent rainfalls and the rainfall attenuation coefficient on a daily basis.Now,extensive debris flows are posing great threats to the mountainous areas of Fujian province,China,which need extensive investigation on their mobilization model.In this study,the situation of debris flows in the mountainous areas of Fujian,China was generally addressed and all methods to determine precedent effective precipitation were documented.By comparing historical data of 8-days and 14-days of precedent rainfall,it was certain that 8-days was a proper parameter serving as the influence period of precedent effective precipitation.By introducing the Grubbs criterion to eliminate anomalous data and using convex hull algorithm to find the outer boundary of scatter data,the power exponential relationship between precedent effective precipitation and 1-hour critical rainfall was established.Moreover,according to the development characteristics of debris flows in Fujian,the influencing factors of rainfall threshold prediction model of debris flows and the future improvement direction were analyzed.According to the analysis,it could be concluded that the debris flow type in Fujian province was mainly slope debris flow type,and the threshold model f(h 60,Re)=h 60-38.93Re-0.12(h 60,hourly precipitation;Re,precedent effective precipitation)based on precedent effective precipitation and short duration heavy rainfall could achieve good prediction effect for debris flow mobilization.The initiation of single gully debris flow was attributed not only to the rainfall of study area but more the underlying surface topography and geomaterial storage of underlying surface.This study can provide an improved method and idea for constructions of rainfall threshold models of debris flows in multi-vegetation covered areas of Fujian province.
作者
张添锋
郭朝旭
ZHANG Tianfeng;GUO Chaoxu(Key Laboratory of Geohazard Prevention of Hilly Mountains,Ministry of Land and Resources,Fuzhou 350002,China;Fujian Key Laboratory of Geohazard Prevention,Geological Engineering Survey in Fujian Province,Fuzhou 350002,China;Fujian Key Laboratory of Green Building Technology,Fujian Academy of Building Research Co Ltd.,Fuzhou 350002,China)
出处
《山地学报》
CSCD
北大核心
2021年第5期701-709,共9页
Mountain Research
基金
福建省生态地质项目(闽地环务[2021]56号)。
关键词
福建山区
临界降雨阈值
泥石流启动条件
前期有效降雨量
mountainous areas of Fujian province
critical rainfall threshold
debris flow initiation conditions
precedent effective precipitation
