降雨型泥石流临界雨量定量分析

QUANTITATIVE ANALYSIS OF CRITICAL RAINFALL-TRIGGERED DEBRIS FLOWS

利用Logistic回归模型对当日雨量和前期有效降雨量进行回归分析,形成了一整套对降雨型泥石流临界雨量进行定量分析的方法,并在辽宁省岫岩县进行了试用。在收集灾害发生当日各雨量站点雨量数据的基础上,采用等值线法将点雨量转变成面雨量,从而获得灾害发生对应雨量,进而采用向前顺推的办法获得灾害未发生时所对应降雨量,并利用Logistic回归模型确定最佳雨量计算天数。然后,基于Logistic回归模型对灾害发生及未发生样本对应的当日雨量和前期有效降雨量进行回归分析,有效降雨量系数分别采用了经验值(0.84)和利用岫岩雨量、水文数据计算得到的实际数值(0.61)。分析结果表明,该方法具有较好的分类效果,可对于泥石流灾害做到了定量化预测,利用两种有效降雨量系数计算得到的结果都具有较好的预报效果。

A multidisciplinary approach based on logistic regression and antecedent effective rainfall was adopted to study the very complex phenomenon of rainfall-triggered debris flows.An integrated method for quantitative analysis of critical rainfall has been promoted.And a test of this approach was applied in Xiuyan,Liaoning Province.Rainfalls are the main inducement factors of debris flows in China.So it is very important to study the relationship between rainfall and debris flows.But many different subjects such as geology,meteorology,hydrology and agrology are mutually acted.So there is not any universal method to calculate the critical rainfall.The rainfall days when debris flows happened or not were collected from rainfall stages.Then point rainfall was converted into surface through isoline method.Thus,the rainfall corresponding to the happening of debris flows was obtained.The rainfall samples of safe days were gained through counting ahead;and the most suitable days for analysis were computed through logistic regression.Then the rainfall and the antecedent effective rainfall of samples were analyzed based on logistic regression.Experiential value(0.84) and actual value(0.61) were respectively adopted as the effective rainfall coefficient.The actual value was computed with precipitation rainfall data and hydrological data of Xiuyan.The good classifying ability of this method was approved,and a quantitative prediction of debris flows was achieved and the effects of using two different coefficients were both satisfying.