摘要
用曼宁公式分析泥石流阻力时 ,不同地区和不同流域之间的糙率n值相差很大 ,即是同一条沟的n值也很分散。若考虑单宽固体物质重量和粗、细颗粒含量之比沿垂线分布的不均匀性之后 ,则使单沟的n值点群分布趋于集中 。
Resistance of debris flow ( n ) calculated from Manning formnla has a property that n value increases with the depth of debris flow adding.The phenomena can be reasonable explained by the total weight of unit width soil particles increasing whty the depth of debris flow adding. The resistance ( n value) varies in different watersheds,and some difference values even reach up to four times.The result can not well explained by the difference of the riverbed roughness in the different watershed,because the viscous debris flow have a pavement on the bed and result in the difference of the bed not great in different watershed.Under the inspiring of only“bottom mud layer”and “inverse grading”existing in depositional profile of debris flow,the author thinks that the coarser particles will move upward the top layer by the acting of shear_colliding force in the motion of the debris flow,and result in more fine materials remained on the bottom bed,and the force decrease as the depth of debris flow adding.According to the above results,we assume a vertical distribution function of coarse and fine particle ratio,and the resistance lawd of the viscous debris flow between Jiangjia Gully and Wudu county which n values differ two times are integrated to the function.
出处
《山地学报》
CSCD
2000年第6期508-513,共6页
Mountain Research
基金
中国科学院"山地灾害-泥石流
滑坡研究"特别支持项目
甘肃省科学技术委员会攻关项目!(GK953-3-7)
