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一、引言渠道衬砌材料的费用,取决于所用衬砌材料的体积。取单位长度,则材料的费用是衬砌厚度和周长的函数,而厚度和周长是由渠道断面的形状决定的,一定的底坡条件下,过水能力也是断面形状的函数。利用这些相互关系,可以确定衬砌材料费用最小的渠道断面。如果渠道用一种材料以均匀厚度衬砌,问题就简化为只要确定一个最佳水力断面。如所用的衬砌材料或衬砌厚度是不同的,则问题就变得复杂。本文要阐说的是:当梯形(或矩形)渠道渠底和两侧单位面积衬砌材料费用不同时,求其最小费用的断面。
I. INTRODUCTION The cost of a channel lining material depends on the volume of lining material used. Taking the unit length, the material cost is a function of lining thickness and perimeter, while the thickness and perimeter are determined by the shape of the channel cross-section. Under certain slope conditions, the water-passing capacity is also a function of the cross-sectional shape. Using these interrelations, it is possible to determine the minimum cross-section of the lining material. If the channel is lined with a single material of uniform thickness, the problem is reduced to just one of the best hydraulic profiles. The problem becomes complicated if the lining material or lining used is of a different thickness. This article is to explain is: when the trapezoidal (or rectangular) channel bottom and both sides of the lining material cost per unit area, seek the least cost section.