岷江上游汶川县佛堂坝沟泥石流特征及危险性分区

Features and risk zonation of debris flow in Futangba Ravine of Wenchuan County of the Minjiang River

佛堂坝沟为岷江上游左岸一级支流,100a来多次发生过严重的泥石流灾害。该沟发育于青藏高原边缘的高山峡谷区,流域相对高差达2470 7m,又处于龙门山地震断裂带内,沟内松散固体物质丰富,激发泥石流的高强度局部暴雨时有发生,泥石流的形成条件充分;通过野外调查和取样试验分析确定,泥石流具有粘度低、固体物质颗粒粗大、重度高,活动频率低、规模大的特征。根据泥石流的特征进行了泥石流分类,对该沟下游和沟口地带按泥石流危险性大小,分出泥石流一级危险区、二级危险区和安全区三级共3个区,并提出减灾防灾措施。

Futangba Ravine,which is a branch in the upper reaches of the Minjiang River,Sichuan Province,China,occurred many times serious debris flows in recent 100 years.The ravine develops in the edge of Qinghai\|Xizang Plateau where the landforms is high mountains and canyons and the relative elevation is about 2470\^7 m.It is located in the Longmenshan Mountain seismic\|tectonic zone where the loose solid material is abundant,severe local torrential rains take place frequently.Conditions of formation for debris flow are ample there.Features of the debris flow have been understudied through field investigate with taking samples and analysis.The features are as follows:the viscosity of debris flow is low,the grain of solid material is buldy,unit weight is high,the activity frequency is low and acale is bit.Types of debris flow were classified by its characteristics.On the foundation of the above work,the ravine downstream is divided into three sections:the first class dangerous section,the second class dangerous section and the safe section.Finally the prevent and control countermeasures have been taken out.