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汶川“5·12”地震以来,四川地区地质构造活动进入活跃期。而芦山“4·20”地震后,雅安地区地质灾害进入高发期。2013年7月4日20时,四川省雅安市石棉县熊家沟暴发了大规模泥石流过程,堵塞竹马河,造成重大经济损失和人员伤亡。为了研究地震后熊家沟泥石流的堵江特征及其防止措施,通过泥石流流域野外调查,发现由于石-甘公路,特别是竹马河的河堤工程,使得熊家沟堆积区地形纵坡突增泥石流在其堆积区运动时,其汇入主河的运动方式发生突变。根据堵江型泥石流堆积区的纵坡变化特征,将该泥石流定义为工程纵坡增加型堵江泥石流。而对比熊家沟“7·04”泥石流物源的前后变化情况,可知其泥石流物源的平均转化率为0.307,且位于下游的泥石流物源更容易被侵蚀。通过熊家沟“7·04”泥石流的水上和水下堆积物筛分试验,发现其中值粒径d60增加值为3.4%,容重增加了3%。运用Spss统计软件和理论分析,得到工程纵坡增加型堵江泥石流的流速、流量与流域特征的关系,及其等衰减特征,为该区泥石流的类型研究及其防治提供一定依据。
Wenchuan “5.12 ” earthquake, Sichuan tectonic activities into the active period. After Lushan “4.20 ” earthquake, geological disasters in Ya’an entered the high-incidence period. At 20:00 on July 4, 2013, a large-scale debris flow broke out in Xiongjiagou County, Shimian County, Ya’an City, Sichuan Province, blocking the Zhumahe River and causing major economic losses and casualties. In order to study the plugging characteristics of the Xijiagou debris flow and its prevention measures after earthquake, the field investigation in the debris flow basin found that due to the embankment project of Shi-Gan highway, especially the Zhuma River, Debris flow in its accumulation area movement, its movement into the main river of sudden change. According to the longitudinal slope change characteristics of the blockage-type debris flow accumulation area, this debris flow is defined as the increase of the type of debris flow in the longitudinal slope of the project. Comparing the foregone changes of XUJIAgou “7.40 ” debris source, we know that the average conversion rate of debris source is 0.307, and the debris source located in the downstream is more likely to be eroded. Through Xiongjiagou “7.40” debris flow of water and underwater sediment screening test found that the median particle size d60 3.4% increase in bulk density increased by 3%. Using Spss statistical software and theoretical analysis, the relationship between the flow rate and the characteristics of the drainage basin debris flow and the isosectional characteristics of the debris flow increased in the longitudinal slope of the project are obtained, which can provide some evidences for the study on the type of debris flow and its prevention and control.