川藏铁路四川段沿线诱发地质灾害降水阈值研究

利用2009—2019年川藏铁路沿线四川段地质灾害数据、国家气象中心逐小时降水量资料，统计了地质灾害与降水的关系，发现研究区89%的滑坡灾害和96.6%的泥石流均发生在汛期，且地质灾害高发路段位于青衣江暴雨区，与四川地区降水时空分布特征相吻合。分析雨型、降雨强度、前期降雨等因子对地质灾害的影响，发现快速激发，中速激发和慢速激发的地质灾害分别约占33.3%、25.9%、40.8%,表明降雨历时并不是影响地质灾害发生的最直接因子，前期降雨的作用不可忽视；结合环境因子对地质灾害进行了分区，基于降雨历时-雨强(I-D)预报模型建立了川藏铁路沿线四川段引发地质灾害的降水阈值分布。利用该降水阈值的分布特征，检验了2019年引发地质灾害的降水量，发现阈值雨量的判别方法较为科学，具有较强的参考价值。

Study on Precipitation Threshold of Geological Disasters along Sichuan Section of Sichuan-Tibet Railway

Based on the geological disaster data of Sichuan section along Sichuan-Tibet railway from 2009 to 2019 and hourly precipitation data of National Meteorological Center,this paper makes statistics on the relationship between geological disasters and precipitation.It is found that 89%of landslide disasters and 96.6%of debris flows occurred in flood season,and the road section with high geological disasters is located in the rainstorm area of Qingyi River.It is consistent with the temporal and spatial distribution characteristics of precipitation in Sichuan.By analyzing the influence of rain type,rainfall intensity and previous rainfall on geological disasters,it is found that geological disasters with rapid excitation,medium-speed excitation and slow excitation account for about 33.3%,25.9%and 40.8%respectively.It shows that rainfall duration is not the most direct factor affecting geological disasters,and the role of early rainfall can not be ignored.The geological disasters were divided according to environmental factors,and the precipitation threshold distribution of geological disasters in Sichuan along the Sichuan-Tibet railway was established based on the rainfall duration-rainfall intensity(I-D)forecast model.Based on the distribution characteristics of the precipitation threshold,the precipitation that caused geological disasters in 2019 was tested,and it was found that the method of judging the threshold rainfall was scientific and had strong reference value.