金沙江白格滑坡运动过程分析及潜在不稳定岩体预测

2018年10月11日和11月3日于西藏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,金沙江右岸先后发生两次滑坡,堵塞金沙江形成堰塞湖,经人工干预险情解除未造成严重损失。采用Voellmy流变模型,基于PCRaster环境使用MassMov2D模拟了两次滑坡的运动和堆积过程,并使用第二次滑坡的反演结果对白格滑坡滑源区的三处潜在不稳定岩体做了预测分析。模拟结果表明:MassMov2D可以用于金沙江白格滑坡这种滑坡-碎屑流的模拟,两次滑坡的主要堆积区域和堆积厚度均于实际情况接近;利用第二次滑坡模拟反演参数预测三处潜在不稳定岩体,假设三处不稳定岩土体同时失稳滑动,会形成64 m高的堰塞坝,可能再次堵塞金沙江形成堰塞湖。

Analysis of Movement Process of Baige Landslide in Jinsha River and Prediction of Potential Unstable Rock Mass Based on MassMov2D

On October 11 and November 3, 2018, at the junction of Baige Village, Boluo Township, Jiangda County, Tibet, and Zeba Village, Ronggai Township, Baiyu County, Sichuan Province, two landslides occurred on the right bank of the Jinsha River, blocking the Jinsha River and forming a barrier lake. The first landslide blocked the Jinsha River and released its natural flow on October 12. The danger was relieved on October 13; The second landslide blocked the Jinsha River again. Under the guidance of relevant departments, the manual excavation of diversion channel was adopted to start the flood discharge on November 12, and the danger was relieved on November 13.Based on the Voellmy rheological model, MassMov2D is used to simulate the movement and accumulation of two landslides in the environment of PCRaster. The inversion results of the second landslide are used to predict and analyze three potentially unstable rock masses in the source area of Baige landslide. The simulation results show that: MassMov2D can be used to simulate the landslide-debris avalanche of Baige landslide in Jinsha River. The main accumulation areas and thickness of the two landslides are close to the actual situation. The inversion parameters of the second landslide simulation are used to predict three potentially unstable rock mass bodies. It is assumed that three unstable rock and soil bodies will slide simultaneously and form a 64 m high barrier dam, which may block up the Jinsha River again and form a barrier lake.