路面坡度对水膜厚度的影响分析

利用满宁公式,推导出水膜厚度的计算公式。通过水膜厚度公式,分别求出水膜厚度关于横坡和纵坡的偏导函数。根据所得偏导函数进行分析,得出结论:关于横坡坡度的偏导函数小于0恒成立,即水膜厚度随着横坡坡度的增大而减小;关于纵坡坡度的偏导函数大于0恒成立,即水膜厚度随着纵坡坡度的增大而增大;横坡与纵坡坡度的偏导函数绝对值之间的比值大于2槡2,即横坡坡度对水膜厚度的影响要大于纵坡坡度。

Impact of Road Slope on Water Film Thickness

Using the Manning formula,the water film thickness formula is deduced.By means of the water film thickness formula,the partial derivative function of the water film thickness on cross slope and longitudinal slope was obtained.According to the analysis on the partial derivative function obtained,it is drawn the conclusion that the partial derivative function on cross slope is less than 0 constantly and it means that the water film thickness decreases with the increase of cross slope gradient;the partial derivative function on the longitudinal gradient is greater than 0 constantly,and it means that the water film thickness increases with the increase of longitudinal gradient;the ratio between the absolute value of the partial derivatives of the cross slope gradient and the absolute value of the partial derivatives of longitudinal gradient is more than 2 2,and it indicates that the cross slope gradient has greater influence on the water film thickness than the longitudinal gradient does.