西藏波密丹卡弄巴冰湖发育特征与潜在风险

    Development characteristics and potential risks of Dankanongba glacial lake in Bomi, Tibet

    • 摘要: 冰湖溃决是青藏高原的典型山地灾害之一,严重威胁川藏交通廊道的安全。开展沿线地区的冰湖灾害调查和溃决风险评估,并制定针对性的防控对策十分必要。选取西藏波密的丹卡弄巴冰湖为研究对象,通过遥感解译、野外调查、工程地质类比、数值模拟等方法,查明了冰湖、冰川积雪区、形成流通区、堆积区等分区流域的发育特征,提出了丹卡弄巴具有发生冰湖溃决和形成泥石流的条件,揭示了高位冰崩、冰川跃动、雪崩等是引发冰湖溃决的主要诱因类型,计算了终碛垄发生全溃的洪水流量曲线,模拟了泥石流在下游沟道的演进过程。结果显示,冰湖全溃条件下形成的泥石流将对堆积区28户85人造成淤埋的直接危害,还将挤占帕隆藏布河,造成主河偏流,对右岸沿河的川藏交通廊道及其附属设施等造成路基水毁的间接危害。对川藏交通廊道沿线冰湖发育区开展灾害调查和风险评估进行初步探索,可供西藏国土空间风险管控、水利水电开发、冰湖景区选址等冰湖灾害评价提供借鉴。

       

      Abstract: Glacial lake outburst flood (GLOF) is one of the serious mountain disasters in the Qinghai-Tibet Plateau, which seriously threatens the safety of the Sichuan-Tibet arterial traffic which is under construction recently.Therefore, it is necessary to carry out professional investigation and assessment of these potential hazard glacial lakes above the railway, and formulate targeted prevention and control countermeasures.The Dankanongba glacial lake in Bomi was selected as the research object, through remote sensing interpretation, field investigation, engineering geological analogy and numerical simulation, to investigate the background characteristics of glacial lake, glacier and snow covered zones, formation and transportation zones and accumulation zones.It is proposed that Dankarongba has the conditions for glacial lake breach and debris flow formation.It is also revealed that high-place glacier collapse, glacier surge and snow avalanche are the main inducement types of GLOF.Based on the calculation of flood discharge of the end moraine breach, the evolution process of debris flow in the downstream channel is also simulated.The results of numerical calculation and analysis show that the debris flow formed under the condition of GLOF will cause direct damage to 85 people of 28 households in the accumulation area.It will also cause diversion of the main stream and indirect damage to the Sichuan-Tibet arterial traffic and their ancillary facilities by the right bank of the river.A preliminary exploration on how to carry out disaster investigation and potential assessment in the glacial lake areas above the Sichuan-Tibet arterial traffic is carried out, which can be used for reference in the natural resource management, water conservancy and hydropower development, glacial lake scenic spot location and other glacial lake disaster assessment in Tibet.

       

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