Recent catastrophic debris flows in Luding county, SW China: geological hazards, rainfall analysis and dynamic characteristics
Recent catastrophic debris flows in Luding county, SW China: geological hazards, rainfall analysis and dynamic characteristics
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DOI：
10.1007/s11069-010-9545-2
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发表时间：
2010-05
期刊：
影响因子：
3.7
通讯作者：
Huayong Ni;W. Zheng;Zongliang Li;Renji Ba
中科院分区：
文献类型：
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作者：
Huayong Ni;W. Zheng;Zongliang Li;Renji Ba
泥石流已成为泸定县重要的地质灾害类型，对城镇、农村、风景名胜区以及矿山、水利等人类工程设施造成了严重的影响。对2005年6月30日发生在该县中部楚泥镇和8月11日发生在该县西南部海螺沟风景区的两次特大泥石流灾害进行了回顾。在野外调查和遥感解译的基础上，对泥石流事件进行了介绍，确定了泥石流发生的触发因素。进一步分析了前期降雨量和日内降雨量等与洪水发生相关的降雨量，建立了基于前期有效降雨量和日内降雨量的幂律函数作为洪水发生的基本警戒线。然后分别计算了水流速度、流量等动力学参数。通过对比和讨论，得出以下结论：（1）前期降雨对泥石流的形成起着重要作用，泥石流主要是基于饱和松散沉积物引起的边坡失稳而产生的;（2）尽管流速较慢，幅度较小，像2005-6-30泥石流这样的斜坡型泥石流由于难以预测和预防，往往会造成严重的破坏;（3）对泥石流灾害认识的错误和防治意识的缺乏，加剧了泥石流灾害的危害程度。该研究对今后泥石流灾害的防治、小城镇建设规划和旅游开发具有一定的指导意义。
About 127 debris flow gullies have been identified, and debris flows have been an important type of geological hazards in Luding County, affecting cities, towns, rural areas, scenic spots and human’s engineering projects, such as mining and waterpower utilizing equipments. In this summary paper, recent two catastrophic debris flow events occurred on June 30, 2005, in Chuni town, in the central of the county, and on August 11, 2005, in Hailuogou scenic spot, in the southwest of the county, respectively, are reviewed. The debris flow events are introduced on the basis of field investigation and RS interpretation and the triggering factors for flow occurrence are identified. Furthermore, the rainfall related to flow occurrence including antecedent rainfall and intraday rainfall is analyzed, and a power-law function which can be used as a basic warning line is established based on both antecedent effective rainfall and intraday rainfall. Then dynamic parameters such as flow velocity and flow discharge are calculated, respectively. Through comparison and discussion, some conclusions are made including (1) The antecedent rainfall played an important role for debris flows which generated predominately based on the slope-instability due to the saturated loose sediments; (2) Despite slower flow velocity and smaller magnitude, the slope-type debris flows just like 2005-6-30 debris flows usually lead to serious damages for the difficulty to forecast and to prevent; (3) The mistaken recognition on debris flow hazards and lack of prevention consciousness strengthen the hazard and damage degree. This research is of certain significance for the prevention and mitigation of debris flow hazards and for the planning of the town building and tourism development in the future.