雷波县白沙村滑坡-碎屑流粒度分布特征与运动过程关系

2017年7月1日,四川省雷波县白沙村发生滑坡-碎屑流灾害,为了揭示滑坡-碎屑流过程中粒度特征的变化情况,在野外调查和无人机航摄数据分析的基础上,通过碎屑流粒度特征的统计分析试验,结合谢德格尔公式对碎屑流运动速度的估算,研究了碎屑流粒度特征与运动过程的关系,结果表明：（1）碎屑流堆积体表层碎石的等效粒径为4~6cm,碎屑流中的巨石等效粒径主要在0.5~1m之间;（2）通过统计堆积体表层碎石粒径的变化情况可反映出碎屑流动能的变化,运移速度增加,碎石粒径越大,携带巨石能力越强,运移速度降低,碎石粒径减小,巨石越容易停积;（3）雷波县白沙村滑坡属于超高速滑坡,地形制约和挡土墙的阻挡是造成该滑坡-碎屑流移动性较低的原因。

Relationship between grain size distribution characteristics and kinetic process of rock avalanche in Baisha village, Leibo county

In First July 2017, a rock avalanche disaster occurred in the Baisha village of Leibo County, Sichuan province. In order to reveal the changes of grain size characteristics, a statistical test of the grain size characteristics of rock avalanche was designed and carried out based on field investigation and aerial photography. Combining with the estimated velocity of rock avalanche , the relationship between the grain size characteristics and the kinetic process was analyzed. The results showed that: (1) The equivalent size of rock avalanche surface was 4-6 cm, and the equivalent size of megalith in the rock avalanche was mainly 0.5-1 m (2) The change of debris particle size can reflect the change of kinetic energy of debris flow. With the increase of migration velocity of rock avalanche, the larger the particle size of the debris, the stronger the carrying capacity of the megalith; with the decrease of migration velocity of rock avalanche, the smaller the particle size of the gravel, the easier the stoppage of the megalith. (3) Rock avalanche in Baisha Village of Leibo County belonged to super-high-speed landslide. Terrain restriction and retaining wall obstruction were the reasons for the low mobility of the rock avalanche.