四川青衣江上游若壁小沟泥石流及其防治对策

若壁小沟为四川青衣江上游左岸的一级支沟,该沟处于深切割高山峡谷区,地形坡度陡,构造发育,岩石破碎,加之较为丰富的降雨,使该沟具备泥石流暴发的条件。该沟如果暴发泥石流,将对某电站拟建厂房产生威胁。该沟泥石流具有成灾快、危害严重、松散固体物质以坡面崩塌补给为主、活动频率中等等特征。通过野外考察和取样分析,该沟泥石流的性质和类型为中频率—中~大规模—低~高粘度泥石质泥石流。分析预测了该沟泥石流在强烈地震条件下、近期出现不同频率暴雨情况下及人类活动影响下的发展趋势。在此基础上,提出了该沟泥石流减灾工程规划方案。

The Debris Flow and Its Controlling Measures of Ruobixiao Gully in the Upper Reaches of Qingyi River of Sichuan Province

Ruobixiao gully in the left bank is one of the first tributaries in the upper reaches of Qingyi River of Sichuan province.It has a drainage area of 5.06 km2,and a total length of 3.56 km.Geological,geomorphologic,and climatic features of the Ruobixiao Gully are presented in this paper.The drainage develops in the eastern slope of the Jiajin mountain area,where the precipitation is very concentrated from May to October accounting for 85～90% of the year,the maximum daily precipitation is 119.1 mm.Therefore,the composition of landform,geology and rainstorm provides favorable conditions for the burst of debris flow.The damage of debris flow in this gully is potential.Through field observation,the characteristic of the debris flow in Ruobixiao Gully can be described as turbulatent～cambic.The density of the gully is 2.0 t/m3,1.9 t/m3,1.8 t/m3 for debris flow of P=1%,2%,5% respectively.The debris flow type of the gully can be defined as middle frequency-middle～large scale-low～high viscosity.The major activity characteristics of debris flow are as follows:(1) The loose solid material for debris flow is mainly supplied by the slope landslip;(2) The debris flow causes rapidly disaster and strong damage;(3) Middle frequency.Debris flow has three development tendencies in this gully,if unreasonable activities of human cease,and the comprehensive controlling measure work,debris flow will become weak.The engineering plans for disaster relief are put forward.After adopting the block,bed stabilization,diversion measures,the damage of debris flow can be mitigated.