川藏交通廊道龙利空泽错冰碛湖溃决危险性评价

Outburst Risk Assessment of Longlikongze Moraine Lake in Sichuan-Tibet Traffic Corridor

以川藏交通廊道龙利空泽错冰碛湖为研究对象,基于该区域1974-2017年遥感影像,利用空间地理处理软件分析、确定冰碛湖上游补给冰川危险冰体,并根据漫顶溃决模型对冰崩入湖引发冰碛湖溃决进行计算,最后应用HEC-RAS模型对冰碛湖溃决进行演进模拟,根据生成的淹没分布图及关键断面水深溃决曲线分析下游泛滥情况。结果表明:1)冰碛湖上游冰陡坎至冰舌段为不稳定冰体,根据溃决临界条件判断其存在发生溃决的可能;2)龙利空泽错冰碛湖溃决诱发因素充足,极易引起漫顶溢流溃坝,最大峰值流量为1011.97 m3/s;3)坝体1/2溃决情况下最大峰值流量为769.49 m3/s,此时下游村落均为低风险区域,坝体全溃情况下对下游查捕村、江查村、仲沙村造成潜在威胁,其中查捕村是重要潜在威胁地区,应重点关注并及时防治。

Taking Longlikongze moraine lake in southeastern Tibet as the research object,based on the remote sensing images(1974 to 2017)and the temperature and rainfall data(1981 to 2017)of the region,the moraine lake and its upstream glaciers were analyzed and evaluated.The moraine lake outburst caused by icefall was discriminated by numerical calculation,and then the HEC-RAS model was used to simulate the evolution of the moraine lake outburst.According to the generated inundation distribution map and outburst curve of the key section water depth,the downstream flooding was analyzed.The results show that:1)The upper reaches of the moraine lake from the ice ridge to the ice tongue are unstable ice bodies,and it is considered that there is a possibility of outburst according to the critical judgment conditions.2)Longlikongze moraine lake has sufficient inducing factors,which can easily cause overflow and dam breach.The maximum peak flow rate is 1011.97 m3/s,and the maximum peak flow rate under 1/2 residual dam breach condition is 769.49 m3/s.3)The downstream villages under the 1/2 residual dam breach condition are all low-risk areas.The flood caused by the dam breach under the full dam breach condition poses potential threats to the downstream Chabu Village,Jiangcha Village and Zhongsha Village.Chabu Village is an important potential threat area and should be focused on prevention and control.