1991年9月23日云南省昭通市头寨沟特大滑坡

A CATASTROPHIC LANDSLIDE OF SEPT. 23,1991 AT TOUZHAIGOU OF ZHAOTONG, YUNNAN PROVINCE

1991年9月23日云南省昭通市境内,发生了一个头寨沟特大滑坡。其属顺层岩质滑坡,位于103°51′11″E,27°34′30″N。滑坡发生区滑体前后缘海拔分别为2230米和2580米,长250米。其间方量约1600万立方米的滑体剪出后,滑落到海拔2060米的沟道内,并遇障碍物,滑体被碎屑化而进入滑动区,滑动方向经三次转折,抵海拔1820米的沟口,滑程全长3000米。滑坡总方量约1800万立方米,滑动历时3分钟左右,致死216人,伤8人,造成直接经济损失近百万元。

At 18 :10 on Sept. 23,1991,a catastrophic landslide at Touzhaigou,located at 30km from northeastern Zhaotong City,on the left bank of Panhe River in Yunnan Province occurred. It belongs to bedded rock landslide and situated at 103°51′11″E,27°34′30″N. The altitude is at 2580-1820m.The total volume of the landslide is about 18Mm3;the sliding length is 3000m,and it lasted 3min. 216 people were killed and 8 ones wounded. The economic loses ;are a million yuan.The characters of Touzhaigou Landslide are.1.The whole slide region may be divided into the occurring area of landslide (the length of sliding body is 250m, the width is 400m and mean thickness is 180m; the volume is 16Mm3 and the altitude is at 2580-2230m)and the sliding area (the length is 3000m and the altitude is at 2060-1820m).2.In the occurring area,the sliding body was broken to pieces and slide into the sliding area and became the sliding debris while it sliped to 170m and ran into obstacle (increased volume of landslide is 2Mm3).3.The sliding body in the occurring area is sliding mass by mass,and the sliding body in the sliding area belongs to driving pattern and is the debris sliding.4.In the sliding area,the sliding body(debris)changed the sliding directions constantly,and accumulated into 4 ridge body in the gully (parallel to sliding direction) and overlapped continuously.At present,in the occurring area,there are 2Mm3material. They would fall.