非均质泥石流起动判别关系式

发布时间：2018-03-25 07:30

本文选题：非均质泥石流　切入点：起动过程　出处：《水利学报》2017年07期

【摘要】：在我国西部山区每年汛期发生不同程度的泥石流灾害,认识非均质泥石流(又称黏性泥石流)的形成机理,判识泥石流的发生条件是准确预测预报泥石流的基础。本文通过48组正交的水槽实验,模拟非均质泥石流形成的动力过程,分析相关起动因子的量化关系。基于泥沙运动力学理论,将Shields数(又称希尔兹数)列为判识泥石流固体颗粒起动的重要参数,分析非均质系数(颗粒铺设方式)、水流量等水沙因子对泥石流起动的响应关系。进一步从泥沙颗粒的受力角度,以水流剪切力与颗粒起动临界剪切力的比值(即起动判别式)作为表征泥石流颗粒起动的参数(其值大于1时表示泥石流颗粒处于起动状态),分别应用Shields起动拖曳力曲线的整体拟合公式和分段拟合公式两种形式,初步建立了非均质泥石流颗粒起动判别式。通过应用蒋家沟实测资料进行验证,表明以Shields起动拖曳力曲线的整体拟合公式得出的起动判别式误差较小,可以应用于泥石流起动条件与致灾临界条件的判识,对我国泥石流防灾减灾具有重要参考价值。
[Abstract]:The formation mechanism of heterogeneous debris flow (also called viscous debris flow) has been recognized in the mountainous area of western China, which has different degrees of debris flow disasters in flood season every year. Recognizing the occurrence conditions of debris flow is the basis of accurate prediction and prediction of debris flow. In this paper, 48 groups of orthogonal flume experiments are used to simulate the dynamic process of the formation of heterogeneous debris flow. Based on the theory of sediment motion mechanics, Shields number (also known as Shields number) is considered as an important parameter to identify the starting of debris flow solid particles. The response of heterogeneous coefficient (such as particle laying mode, water discharge and other factors) to debris flow incipient is analyzed. Further, from the point of view of the stress of sediment particles, The ratio of flow shear force to critical shear force of particle starting (i.e. starting discriminant) is taken as the parameter of debris flow particle starting (whose value > 1 indicates that debris flow particle is in the starting state). Shields is used to start the debris flow particle respectively. The integral fitting formula and the piecewise fitting formula of drag curve are two forms. The incipient discriminant of heterogeneous debris flow particles is established preliminarily. By using the measured data of Jiangjiagou, it is shown that the error of starting discriminant derived from the integral fitting formula of Shields starting towing force curve is small. It can be used to judge the starting condition and the critical condition of debris flow, and has important reference value for the prevention and mitigation of debris flow in China.
【作者单位】：北京师范大学环境学院水沙科学教育部重点实验室;水利部国际经济技术合作交流中心;长江科学院水土保持研究所;
【基金】：国家自然科学基金项目(11372048) 长江科学院开放研究基金项目(CKWV2015225/KY)
【分类号】：P642.23

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