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近年来,在异常强降雨下,秦巴地区大型滑坡、泥石流灾害频繁发生,尤其是高陡斜坡上罕见的坡面型泥石流不仅突发性强,而且成灾面积大,造成的经济损失十分惨重。本文以2003年8月29日发生于秦岭造山带腹地宁陕县城区的坡面型泥石流为例,通过野外地质调查和室内试验测试,分析了暴雨作用下宁陕城区高陡斜坡带坡面型泥石流的发育特征及其形成机理。作者认为,除了持续集中的特大暴雨和斜坡陡峻等因素外,斜坡表层残坡积物的物质组成尤其是残坡积土的粘粒含量和粘土矿物成分是坡面型泥石流大面积同时发生的重要控制性因素。通过不同含水状态下的粘性土抗剪强度试验结果统计分析,剖析了暴雨坡面型泥石流的形成过程,探讨了斜坡浅表层残坡积物快速流动变形的临界状态,从而为地质灾害预测预警提供了科学依据。
In recent years, large-scale landslide and debris flow disasters have occurred frequently in the Qinling-Bashan area during unusually heavy rainfalls. In particular, the rare slope-type debris flows on high and steep slopes are not only unexpected but also have a large area of disastrous damage and cause heavy economic losses . In this paper, taking the slope-type debris flow occurring in the urban area of Ning Shan county, the hinterland of the Qinling orogenic belt on August 29, 2003 as an example, the slope type of high-steep slope zone Development Characteristics and Formation Mechanism of Debris Flow. The author believes that in addition to continuous heavy rainfall and steep slopes and other factors, the material composition of the slope surface sediments, especially the residual clay and clay mineral composition is a large area slope debris flow simultaneously important Controlling factors. Based on the statistic analysis of shear strength test results of cohesive soil under different water contents, the forming process of storm debris slope debris flow was analyzed, and the critical state of rapid flow deformation of debris in shallow surface of slope was discussed to provide the prediction and warning of geological disasters The scientific basis.