文章提出弓形面积和弧长计量的实用公式，并分析了该公式的相对误差。

This paper puts forward some practical formulae of measuring the area and arc length of arch form, and analyses the relative error of these formulae.

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脱泥弧弓形缺陷与扒土板均匀相间。

The bow defects of the desliming arc are evenly alternated with the raking soil boards;

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