关键词: 地形条件, 河床类型, 水动力分析, 形成机理, 堰塞湖地形

Abstract:

The barrier dams can be divided into 3 types according to the formation mechanism, namely, the landslide-induced type, collapse-induced type and debris flow-induced type. The topographical conditions, riverbed conditions and hydro-dynamic conditions for the formation of the landslide-induced barrier dams, accounting for more than 70% of the barrier dams, are analyzed. The formation possibilities of barrier dams under different conditions are obtained, and the areas where the barrier dams are easily formed in China are analyzed. On the basis of the formation conditions, the 5 stages of the barrier dam formation are analyzed, including the creep-crack, shear planes penetration, dramatic initiation, leaping at high speed in air, dam forming by gravity collision after crashing and bouncing down. The study showed that the landslide-induced barrier dam would be easily formed in inclined slope area with where the slopes are 30°to 50。 with shallow water and narrow riverbed.

Key words: topographical conditions, types of riverbed, hydro-dynamic analysis, formation mechanism, topography of the barrier dam