Abstract Two successive Baige landslides are presented in this study to investigate the dynamics and emplacement mechanisms. Field survey shows that the deposit characteristics of the first landslide are affected by the extremely fractured rock masses and the complex spatial distribution of lithologies in the source area. This deposit consists of abundant angular megablocks on the surface supported by clasts, with a relatively abundant content of rubble ranging from micrometre to decimetre sizes, and rarely well-preserved original stratigraphic sequence, diapiric structure, and convoluted structure. These sedimentological characteristics imply that a simple differential shear process, induced by compression, is distributed through the entire avalanche masses with low internal disturbance during the emplacement of the first landslide. The three-dimensional discrete element simulations show that: (i) the first landslide reaches its maximum average velocity of 41 m/s in ~28 s and eventually is bulldozed to a halt in the river within ~80 s. (ii) The second landslide is controlled by entrainment, which impedes the avalanche from further accelerating, and simultaneously imparts kinematic energy to the substrate, eventually becoming entirely mobilized and reaching a maximum average velocity of 35 m/s in ~36 s. In the dynamic process of the second landslide, the significant entrainment-induced enlarged volume (its entrainment ratio reaches 3.3) is associated with the steep concave terrain, water-bearing substrate and lower-roughness substrate basal boundary, and overloading-impact-induced erosion is proposed to be the most significant contribution to this entrainment.

中文翻译：

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金沙江上游白鸽连续滑坡动力学及侵位机制

摘要 本研究介绍了两个连续的白格滑坡，以研究其动力学和就位机制。现场勘察表明，第一滑坡的沉积特征受震源区岩体极度破碎和岩性空间分布复杂的影响。该矿床由大量碎屑支撑的地表角状巨块组成，碎石含量从微米级到分米级不等，原始地层层序、底辟构造和盘绕构造保存完好，极少见。这些沉积学特征表明，在第一次滑坡就位期间，由压缩引起的简单的差动剪切过程分布在整个雪崩体中，内部扰动很小。三维离散元模拟表明：(i) 第一次滑坡在约 28 秒内达到其最大平均速度 41 m/s，并最终在约 80 秒内被推土机停在河中。(ii) 第二次滑坡受夹带控制，阻止雪崩进一步加速，同时将运动能传递给基底，最终完全移动并在约 36 秒内达到最大平均速度 35 m/s。在第二次滑坡的动力过程中，显着的夹带增大体积（夹带比达到3.3）与陡峭的凹陷地形、含水基底和低粗糙度基底边界以及超载冲击引起的侵蚀有关。被认为是对这种夹带的最重要贡献。