市政工程施工中经常用到圆曲线的放样。精确的圆曲线放样方法很多,但都比较复杂。对于大量精度要求不高的圆曲线放样,比如图1所示厂区道路的圆弧段连接,如果采用坐标法、总偏角法或弦线偏距法,就不合算。下面介绍一种放线方法,概括成口诀就是:“弧长一半, In the construction of municipal engineering, the drawing of circular curves is often used. There are many ways to lay out an accurate circular curve, but they are more complicated. For a large number of low-precision circular curve lofting, such as the arc section of the road in the plant area shown in Figure 1, if the coordinate method, the total declination method or the string offset method, is uneconomical. Here’s a way to put the line out. Summarizing the recipe is: ”Half the arc length,