渗流作用下岸坡泥沙起动流速研究  

Research on riverbank sediment incipient motion velocity under seepage effect

作　　者：李林林[1] 张根广[1] 

机构地区：[1]西北农林科技大学水利与建筑工程学院,陕西杨凌712100

出　　处：《人民长江》2017年第23期84-88,共5页Yangtze River

基　　金：国家自然科学基金项目(51279170)

摘　　要：渗流和冲刷作用是河流岸坡发生崩岸的重要因素。基于概率论与泥沙运动基本原理,引入起动概率及相对暴露度,采用滑动起动模型,推导了渗流作用下岸坡泥沙起动流速的统一公式,弥补了已有研究成果缺乏对泥沙起动概率和渗流力考虑的不足。在简化的起动边界条件下,所得公式可以简化为顺直岸坡、正负坡以及平坡等条件下的起动流速公式。经过有渗流力及无渗流力两种起动条件下的实测资料验证,表明所得公式计算结果与实测数据符合良好。相关结果有助于深入理解泥沙起动及河道岸坡崩岸机理。The seepage and erosion are the key factors for riverbank collapse. In this paper,based on the probability theory and basic principle of sediment movements,we introduce threshold probability and relative exposure degree and use the sliding-incipient model to deduce a unified formula of riverbank sediment incipient motion velocity in consideration of the seepage effect.The presented model makes up the deficiency of the exiting studies that do not consider the incipient probability and seepage force. Under simplified incipient boundary condition,the unified formula can be simplified into the incipient motion velocity equation adapting to the straight slope,positive and negative slope,horizontal ones and so on. As the verification shows,the calculated sediment velocity is well consistent with the measured data in two conditions of with and without seepage effect. The results are helpful to deeply understanding the sediment incipient motion and riverbank collapse mechanism.

关 键 词：渗流 岸坡 起动概率 相对暴露度 起动流速 

分 类 号：TV14[水利工程—水力学及河流动力学]