芦山“4·20”地震后宝兴县城打水沟泥石流发育趋势及防治方案  

The Potential Tendency and Mitigation Measures of Dashui Gully in Baoxing Coutny after Lushan“4·20”Earthquake of Schuan

作　　者：游勇[1] 柳金峰[1] 陈兴长[2] 

机构地区：[1]中国科学院山地灾害与地表过程重点实验室/中国科学院水利部成都山地灾害与环境研究所,四川成都610041 [2]西南科技大学环境与资源学院,四川绵阳621010

出　　处：《山地学报》2013年第4期495-501,共7页Mountain Research

基　　金：中国科学院重点部署项目(KZZD-EW-05-01);国家科技支撑计划课题(2011BAK12B03)资助~~

摘　　要：打水沟为宝兴河右岸的一级支流,位于宝兴县城城区,流域面积1.01 km2,主沟长度1.85 km,主沟比降640‰。受芦山"4·20"地震的影响,流域中下游直接引发了大量的崩滑体,加之地形陡峻,且位于青衣江-鹿头山暴雨区边缘,极容易发生泥石流。一旦发生泥石流,将会对沟口建筑和人员的安全造成巨大危害。通过对打水沟地震前后遥感影像的解译,结合野外考察,综合判定该沟为地震触发的潜在性泥石流沟。进一步分析估算,由于地震震动导致流域内发育6处崩塌体,总面积20 375 m2,松散固体物质总量为15.20×104m3。在分析泥石流形成条件与发展趋势的基础上,提出了打水沟泥石流减灾方案,并对泥石流排导槽梯形最佳过流横断面进行了设计。通过计算分析得到,在排泄设计标准的泥石流时,排导槽的最佳过流断面宽度为2.38 m,深度为2.23 m。The Dashui gully is a right-bank branch of the Baoxing River, located in Baoxing County, one of the are- as most affected by the Lushan＂4 · 20＂ Earthquake, Sichuan, China. The gully has a basin area of 1.01 km2, is 1.85 km long, and the gully＇ s longitudinal slope is 640 %. The gully was lack of sediment supply conditions be- fore the earthquake. After earthquake, 6 landslides varying in size were induced by the earthquake and distributed in the middle and lower reaches. Together with the steep high landform conditions and favorable rainfall conditions, debris flow will be easy to form and cause great damages to buildings and human lives at the outlet area. Based the satellite images interpretation before and after the earthquake and the filed investigation, the loose solid materials, catchment integrated coefficient, relative cutting degree, mean channel gradient, mean hillside gradient and stra- tum lithology were selected as identification factors. Then, the Dashui Gully was identified as an earthquake-in- duced potential debris flow torrent. The 6 landslide induced by the earthquake cover an area of 20 375 m2 with a to- tal volume of 15.20 x l04 m3. Based on the formation conditions and potential tendency, the debris flow mitigation measure was proposed and the optimal cross-section design for the trapezoid shaped debris flow drainage canal of the gully is discussed. After calculation, the width and depth of the optimal trapezoid shaped debris flow drainage canal were equal to 2.38 m and 2.23 m respectively for draining the debris flow of 50 years return period.

关 键 词：芦山“4·20”地震 宝兴县 打水沟 泥石流 潜在性 防治方案 

分 类 号：P642.23[天文地球—工程地质学]