卵砾石床面的统计粗糙特性

发布时间：2018-05-04 20:45

本文选题：卵砾石床面 + 粗糙特性　；参考：《工程科学与技术》2017年06期

【摘要】：针对代表粒径法难以准确量化床面总体粗糙特性的问题,引入统计学理论研究卵砾石床面的粗糙特性,采用不同粒径组成的天然卵砾石颗粒人工铺制了多种散叠型床面,基于床面激光扫描试验资料并结合他人试验成果,探讨床面粗糙统计参数随颗粒组成的变化关系,分析剖面轮廓及粗糙床面的高程变异特征。结果表明:床面高程频率分布呈负偏态,形态较正态分布陡峭,为峰度Ku3的高狭峰;高程标准差σz随中值粒径d50的增大而增大,偏度Sk随d50的增大而减小;在d50相同的情况下,人工铺制床面的σz和Sk值均小于清水冲刷粗化床面,而Ku值并无明显差异。剖面轮廓的1维结构函数满足变异函数球状模型,模型参数包括变程、块金值和基台值,变程随d50和σz均呈先减小后增大的趋势变化,块金值、基台值随d50和σz均呈单调递增变化,变化趋势可用2次多项式曲线拟合。床面2维结构函数的分布形态与抽样尺度hx、hy密切相关,hx、hy与d50相当时,2维结构函数分布形态接近圆形,床面粗糙具有各向同性,与清水冲刷粗化床面的结构函数分布规律一致;随着hx、hy的增大,2维结构函数分布形态复杂性明显增加,不同象限的结构函数值差异较大,且不再具有清水冲刷粗化床面结构函数的分布规律,床面粗糙出现各向异性。
[Abstract]:In order to solve the problem that it is difficult to quantify the overall roughness of the bed surface accurately by the representative particle size method, the statistical theory is introduced to study the roughness of the gravel bed surface, and a variety of scattered bed surfaces are made by using natural gravel particles with different particle sizes. Based on the laser scanning test data of bed surface and other experimental results, the variation of statistical parameters of bed roughness with particle composition is discussed, and the profile profile and height variation characteristics of rough bed surface are analyzed. The results show that the frequency distribution of bed height is negative skewed, and its shape is steeper than that of normal distribution, which is a high narrow peak of kurtosis Ku3, and the standard deviation 蟽 z increases with the increase of median particle size d _ 50, and the deviation k decreases with the increase of d _ (50). Under the same condition of d _ (50), the height standard deviation 蟽 _ z increases with the increase of d _ (50). The values of 蟽 _ z and S _ k of artificial bed surface are lower than those of clean water scouring coarsening bed surface, but there is no obvious difference in Ku value. The 1-D structural function of the profile satisfies the spherical model of the variation function. The parameters of the model include variable range, block gold value and base station value. The variation range decreases first and then increases with d _ (50) and 蟽 _ z, and the block gold value increases. The base value increases monotonously with d50 and 蟽 z, and the change trend can be fitted by polynomial curve of order 2. The distribution of 2-D structural function of bed surface is closely related to the sampling scale (HXHY). When the distribution form of 2-D structural function is close to circular, the roughness of bed surface is isotropic, which is consistent with the distribution law of structural function of roughened bed surface washed by clear water. With the increase of hxhy's size, the morphological complexity of the two dimensional structural functions increases obviously, and the structural functions of different quadrants differ greatly, and there is no longer the distribution law of the structural functions of the roughened bed surface with clear water scouring, and the roughness of the bed surface appears anisotropy
【作者单位】：重庆交通大学国家内河航道整治工程技术研究中心;重庆交通大学水利水运工程教育部重点实验室;四川大学水力学与山区河流开发保护国家重点实验室;
【基金】：国家自然科学基金资助项目(51509026) 重庆市基础科学与前沿技术研究资助项目(cstc2017jcyj AX0278)
【分类号】：TV147

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