西藏波密易贡高速巨型滑坡特征及减灾研究

20 0 0年 4月 9日晚 ,西藏林芝地区波密县易贡藏布河发生巨型高速滑坡。滑坡经历了高位滑动—碎屑流—土石水气浪—泥石流—次级滑坡等过程 ,具复合性。滑坡由 5 5 2 0 m高程的雪山向下高速滑动 ,历时约 10 min,滑程 8km,堆积于约2 190 m高程的易贡藏布江 ,形成坝高 5 4m,长约 2 5 0 0 m,库容可达 2 88× 10 8m3,体积约 2 .8× 10 8～ 3.0× 10 8m3的滑坡堰塞湖。为了减轻水位上涨对湖区 40 0 0多人员的淹没危害和防止滑坡“溃坝”对下游 318国道及雅鲁藏布江大峡谷地区的危害 ,采用了在坝体开渠引流降低溃坝高程和湖水库容的减灾措施。

The rapid huge landslide occurred in Yigong River in the Bomi, Tibet, on the April 9,2000. The landslide processing is divided into four stages: a)high place sliding and fall at the elevation 5500m; b)avalache; c)mix flow and wave with mud, rock, snow water, air; c)mudflow, secondary landslide, lasted 10 minutes. A “landslide dam” is formed suddenly with 2500m long, 2500m wide, 60m high, 280～300 million m 3 in volume and a landslide\|blocked lake is born holy. To reduce drown hazard in the lake area and flooding disaster in the lower reaches, a measurement of excavate trench is applied.