滑坡、泥石流堰塞湖灾害主要的成灾特点与减灾对策

Major Disasters and Countrtmeasures of Dammed Lakes from Landslides and Debris Flows

"5·12"汶川特大地震,在灾区形成了大量堰塞湖,具有明显危害的达34处,严重地危害或威胁到上下游人民生命财产安全。为了及时有效地处置和减轻堰塞湖灾害损失,收集、分析了我国西部一些滑坡、泥石流堰塞湖灾害的形成、危害和处置的资料,启示如下:滑坡、泥石流形成的堰塞湖灾害往往较滑坡、泥石流本身的灾害更严重;滑坡堰塞湖一般较泥石流堰塞湖规模大,堵塞时间长,危害更严重;大地震既能形成滑坡堰塞湖,余震又能造成其溃决;冰湖溃决泥石流易堵塞江河,形成堰塞湖;控制或减缓湖水位上涨,尽早在水位较低时泄流是滑坡、泥石流堰塞湖首选的减灾对策。

The 5 · 12 Wenchuan earthquake resulted in a number of landslides and debris flows which formed dozens of dammed lakes in the quake-hit area. Among these quake lakes, 34 are of high risk of failure, threatening cities and towns downstream. For the purpose of preventing the dam failure, this paper reviews some failure events of dammed lakes formed by landslides and debris flows in the southwest and draws conclusion as follows： the dammed lake has higher potential of damage than the landslide and debris flow that formed it; landslide lake is often larger than debris flow lake and also has a longer duration and hence higher risk; the quake lake is prone to break during the aftershock and causes more disasters. In practice, the limiting of water level and timely draining of the lake are the primary control measures to prevent the potential disaster.