冕宁县白泥巴沟泥石流特征及治理对策.docVIP

冕宁县白泥巴沟泥石流特征及治理对策 　　摘要：白泥巴沟位于安宁河断裂中段，受断块差异升降运动影响，泥石流活动发育。根据“面积-高程分析法”定量计算，白泥巴沟地貌发育处于壮年期，利于泥石流的形成，泥石流潜在危险性等级达中型。泥石流的物源由崩塌堆积物、滑坡堆积物、沟道堆积物和坡面侵蚀物四部分组成，松散固体物源总量为2139万 m3，可能参与泥石流活动的物源动储量为488万 m3。通过实地调查分析，该流域环境动态的不稳定性，是造成泥石流易发的主要因素，暴发中小型黏性泥石流的机率达85%以上。建议采用“以拦为主、多级拦挡”的措施进行泥石流工程防治。 　　关键词：白泥巴沟；泥石流；侵蚀特征；物源特征；发生机率 　　中图分类号：P642.23 文献标志码：A 文章编号2015 　　Features and measures of Bainiba gully debris flow in Mianning County 　　GUO Ning 　　（School of Engineering and Technology，Xichang College，Xichang 615013，China） 　　Abstract：Bainiba gully is located in the middle section of the fault zone in the Anning River，where debris flow is well developed due to the influence of vertical lifting and depressing with difference in fault blocks.Based on the quantitative calculation of the areaaltitude analysis method，the geomorphic development is in the adult stage and beneficial to the formation of debris flow，and the hazard potential grade of debris flow is medium.The debris flow source consists of four parts，including eboulement accumulation，landslide accumulation，gully deposit，and slope erosion material.The total quantity of loose solid material is 2139×104 m3，and the possible dynamic reserve contributing to the debris flow is 4.88×104 m3.Through site investigation and analysis，the instability of dynamic environment in the basin is the main factor to cause debris flow，and the occurrence probability of small and mediumsized viscous debris flow is more than 85%.The proposed measures for debris flow prevention are mainly multilevel obstruction. 　　Key words：Bainiba gully；debris flow；erosion features；source features；occurrence probability 　　冕宁县泸沽镇大春村白泥巴沟流域曾在2006年暴发过泥石流，2009年暴发过洪水。但近年来，沟内崩塌、滑坡等地质现象大量出现，地表松散破碎，坡面侵蚀加剧，松散固体物源量大增，泥石流爆发频率可能达到中频甚至高频状态。白泥巴沟一旦暴发泥石流，将潜在威胁到沟口大春村二社和一个矿区，涉及80户约500人的生命财产安全，另有县道桥梁一座，成昆铁路桥梁一座，潜在经济损失达1 000万元以上，泥石流潜在危险性等级达中型[1]。 　　1 泥石流形成条件 　　1.1 地层岩性及构造 　　区内基岩为震旦系开建桥组（Zak）流纹岩、凝灰岩等，厚度200～485 m。在沟道两侧陡坡地带及沟床内广泛分布，其强风化层厚1～5 m不等。 　　地表第四系（Q4）地层为崩塌滑坡堆积、坡洪积层及