四川汶川茶园沟泥石流灾害特征及危险度评价

2003年8月9日四川汶川县茶园沟泥石流造成了1人死亡,10人失踪和严重的财产损失.泥石流是由于短历时高强度的大雨激发而形成的.泥石流最大流速为10.8m/s,泥石流洪峰流量为999m3/s,冲出物方量约为5万m3.茶园沟流域内松散固体物质的密度为2.18 g/cm3,含水量为10.7%,空隙率为28%,塑性界限和流性界限分别为18.8%和32.5%,一遇大雨或较长时间的降雨就极易形成泥石流.茶园沟属中度危险的泥石流沟,中度危险的泥石流也造成了严重的人民生命财产的损失,这主要是由于受灾对象,即易损性的特性所决定的.茶园沟泥石流的防灾减灾措施,一是要实行封山育林,停止开矿弃渣;二是要提高公路桥梁的防洪标准,合理布局水利水电设施.

Characteristics and hazard assessment of debris flow in Chayuan Gully of Wenchuan County in Sichuan

The debris flow occurring on August 9, 2003 in Chayuan Gully of Wenchuan County of Sichuan, caused 1 death, 10 the missing and serious loss of property. Debris flow was triggered by the short duration and high intensity rainstorm. The maximum velocity of debris flow was 10.8 m/s. The maximum discharge of debris flow was (999 m~(3)/s.) The runout deposits of debris flow were about 50 000 m~(3). The density of the loose materials in Chayuan Gully is 2.17 g/cm~(3), and the water content is 10.7%, and the porosity is 28%. Plasticity limit of the materials is 18.8%; liquefaction limit of the materials is 32.5%. When runing into big storm or long-lasting rain, debris flow easily occurs in the catchment. Chayuan Gully is classed as moderate hazardous catchment, but the catchment likewise caused serious losses of life and property. This is mainly because of the characteristics of the vulnerability in the catchment. The countermeasures against debris flow in Chayuan gully is, on the one hand, to reforest the catchment and stopping mining; on the other hand, to rebuild the highway and bridge with a higher standard to prevent debris flow, and reasonably layout the electric infrastructure.