金沙江杀威台子滑坡成因动力学特性研究

规模巨大的金沙江杀威台子滑坡形成于约4万年前,现存体积约2.69×108 m~3,其堆积体物质结构表现出典型强动力触发的溃散型滑坡特性。进一步的离散元数值反演分析成果表明:山体内广泛发育的结构面是控制斜坡稳定的关键;a_(max)=0.4g为斜坡岩体保持整体稳定的极限动力荷载,形成高速远程运移碎屑流溃散型破坏的临界动力荷载为a_(max)=1.3g;滑坡的成因机理是底部剪切滑移锁固段岩体在强震作用下无法抵抗上部岩体的推挤而触发溃屈破坏;滑体前端受底部摩擦逐渐减速,中后部物质在强大的地震惯性力驱动下,仍以较大速度猛烈撞击前部低速滑体并抛射形成溃散型碎屑流,这是滑坡前部物质极具冲击力并远程运移越过河床甚至急剧爬坡冲覆于岸坡之上达200m的关键动力学原因。

The Genetic Dynamics Characteristics of the JinshaRiver Shaweitaizi Landslide

The massive Shaweitaizi landslide in the Jinsha River was formed about 40,000 years ago, and its existing volume is about 2.69 × 10⁸ m³. The material structure of the accumulation body shows typical collapse landslide characteristics of strong dynamic triggering. Further analysis results of discrete elemental inversion show: The extensive structural surfaces in the mountains are the key factors on slope stability controlling. The ultimate dynamic acceleration of the slope rock mass is a_max=0.4g , and the critical dynamic load for collapse flow formation is a_max=1.3g. The mechanism of landslide formation is that the bottom shear-slip-locked section cannot resist the pushing of the upper rock mass under the action of strong earthquake, resulting in buckling failure. During the sliding of the landslide, the front slide body decelerated gradually with the action of bottom friction, but the mid and back materials driven by a strong earthquake still had great speed. The mid and back materials hit the front material and formed debris flow, which is the key reason that the front materials of the landslide had a great kinetic energy. The front deposits of the landslide transported remotely across the riverbed and even climbed to the opposite slope to a height of 200 m.