金沙江白格“11·29”滑坡成因机理及堵江风险分析

    Failure mechanism and river-damming risk analysis on "11·29" Baige Landslide on Jinsha River

    • 摘要: 金沙江白格滑坡经历了2018年10月和11月的两次堵江后,其后缘上编号为K1、K2、K3的3处残留崩滑体规模较大,有再次滑落堵江的可能性。2022年11月29~30日部分块体发生滑坡,未发生滑坡堵江灾害,但稳定安全问题不容乐观。针对新发险情,对白格滑坡残留体开展工程地质调查、物探、地表位移监测等工作,查明了K1-2、K1-3两处残留体历史变形破坏现象与潜在失稳规模;利用PFC3D颗粒离散元数值模拟技术,建立ball-wall模型,预测两处残留体可能失稳情况的运动过程与堆积形态,并用“四棱台堵江计算”方法进行验算,对残留体堵江风险进行科学评价。结果表明:K1-3块体现处于蠕滑阶段,变形较大,存在整体下滑趋势,其南侧K1-2块体变形较小,整体破坏可能性较低;极端情况下,若K1-3整体下滑导致K1-2块体失稳,二者一同整体破坏,会在金沙江上形成坝高约46.19 m的堰塞体,存在一定的滑坡堵江风险。

       

      Abstract: After two consecutive river-blocking events at the Baige Landslide site on the Jinsha River in October and November 2018, three large remnant landslide masses (K1, K2, K3) remain in the source area, which still pose a potential threat of renewed failure and river damming. A partial reactivation occurred from November 29 to 30, 2022, which did not cause another river blockage but highlighted ongoing stability issues. In response to this renewed hazard, this study conducted engineering geological surveys, geophysical exploration, and surface displacement monitoring on the residual masses, focusing on K1-2 and K1-3. The investigation clarified their historical deformation patterns and potential failure volumes. Using the discrete element method (DEM) with PFC3D, a ball-wall model was developed to simulate the post-failure motion and depositional morphology of potential instability scenarios. The river-damming risk was evaluated quantitatively by applying a "truncated pyramid volume" calculation method. The results show that the K1-3 mass is currently in a creeping stage with significant deformation and a trend towards overall failure, while the adjacent K1-2 mass exhibits minor deformation and a lower likelihood of large-scale failure. However, in an extreme scenario in which the overall failure of K1-3 triggers the instability of K1-2, the combined slide could form a landslide dam approximately 46.19 m high in the Jinsha River, indicating a significant risk of landslide blocking the river.

       

    /

    返回文章
    返回