盆缘山区长江袭夺作用孕灾规律分析

Analysis on geohazards gestation law due to Yangtze River′s capture in basin-edge mountainous region

为研究长江袭夺作用对支流地质体孕灾规律的影响,以重庆市巫溪县为研究区,通过分析长江地质历史资料,研究了长江的形成及其对研究区内大宁河袭夺作用的地质过程;运用点核密度统计等方法,分析了袭夺作用的孕灾规律;此外,对比了在相似的河流规模及地质背景下,被袭夺的大宁河与区内另外2条主要河流在灾害体发育数量和密度上的显著差异。结果表明:地质灾害呈沿主要河流条带状分布、溯源发展的发育规律;地质灾害密集发育区与大宁河沿线高度重合;大型河流的袭夺作用为地质灾害营造了环境条件,是重要的地质灾害风险评价因子。研究成果可为地质灾害风险评价区划及风险管控措施制定提供参考。

In order to study the effects of Yangtze River′s capture on geohazards breeding law of its branch streams,Wuxi County of Chongqing City was taken as the research area,and the formation of the Yangtze River and the geological process of its capture on Daning River in the research area were studied by analyzing the geological historical data of the Yangtze River.Point kernel density statistics was used to analyze the law of geohazards gestation under influence of river capture.Furthermore,the significant differences of the number and density of geohazards between the Daning River that was captured by the Yangtze River,and the other two main rivers under similar river scales and geological backgrounds were compared.The results showed that geohazards developed along a belt shape and showed a source-oriented development.The high density area of geohazards gestation coincided with the Daning River highly.The capture of large rivers created an environment for geohazards development,which was an important factor in geohazards risk evaluation.The research results can provide a reference for geohazards risk evaluation zoning and risk control measures.