2018年10月和11月金沙江白格两次滑坡-堰塞堵江事件分析研究

    STUDY ON SUCCESSIVE LANDSLIDE DAMMING EVENTS OF JINSHA RIVER IN BAIGE VILLAGE ON OCTORBER 11 AND NOVEMBER 3, 2018

    • 摘要: 2018年10月11日和11月3日,在西藏自治区江达县波罗乡白格村与四川省白玉县绒盖乡则巴村交界处金沙江西藏岸(右岸)先后两次发生大规模高位滑坡,堵塞金沙江,形成堰塞湖。尤其是第二次滑坡-堰塞堵江,因坝体过高(堰塞湖水位可到50 m),堰塞湖库容较大(超过5×108 m3),不得不通过修建导流槽主动降低堰塞湖水位。经过人工干预,第二次堰塞体于11月13日被完全冲开,险情得以解除,但下泄的洪水在下游四川、云南境内仍造成严重的洪涝灾害。本文通过对两次滑坡的现场地质调查,结合历史遥感影像解译、InSAR监测、无人机航拍、地面变形监测等技术手段,查明了白格滑坡区斜坡的变形历史、两次滑坡及其堰塞堵江的基本特征及其动态演化特征,简述了第二次滑坡-堰塞体的应急处置以及为保证现场施工安全所开展的"实战性"监测预警工作。在同一部位先后两次发生大规模滑坡堵江事件并对其采取了及时有效的应急处置,其案例非常典型,对类似地质灾害事件具有很好的参考借鉴意义。

       

      Abstract: A large-scale landslide occurred in Baige village, at the border between Tibet Autonomous Region and Sichuan Province, on October 11, 2018. The sliding mass detached from a high-elevation mountain ridge, then dammed the Jinsha River impounding a barrier lake. This initial lake drained naturally. Afterwards, on November 3, a second landslide involved with a large mass of loose material from the first event blocked the river again, inducing a 50 m high dam and a barrier lake with a capacity of 500 million cubic meters. In order to alleviate the dangers of potential dam-breach flood, the artificial spillway was constructed allowing controlled breaching until November 13. However, downstream flooding still cause a major loss of property and damage, covering a large area of Sichuan Province and Yunnan Province. Extensive on-site investigation, combined with historical satellite images interpretation, InSAR monitoring, UAV aerial photography and ground deformation monitoring techniques, was conducted in this paper, to analyze the historical deformation of the study area and the evolutional characteristics of these two events. Based on that, the emergency measurements after each event have been developed, and the implementation of spillway was secured by monitoring and early-warning work at site. The successive landslides damming the Jinsha River presents a good example to study the emergency response and mitigation plan for similar cases in the future.

       

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