一般混合结构民用建筑施工中,需要把轴线投到楼层,在多层框架结构工程中,每层的轴线也需要把它投到上面的一层。这项工作通称翻线。具有丰富实践经验的工人常用垂球吊线的方法,保证上、下层的轴线能在一条铅垂线上,偏差小于容许范围。垂球吊线的精度受一些因素的影响,实践和理论研究证明:垂线投点的误差与垂球线的直径d、垂球线的长度H成正比,与垂球的重 In the construction of civil structures with general mixed structures, it is necessary to cast the axis to the floor. In the multi-story frame structure project, the axis of each layer also needs to be cast on the upper layer. This work is known as turning the line. Workers with extensive practical experience often use the method of hanging the ball to ensure that the axis of the upper and lower layers is on a vertical line, and the deviation is less than the allowable range. The accuracy of the suspended ball is affected by some factors. Practical and theoretical studies have proved that the error of the vertical line is proportional to the diameter d of the vertical line and the length H of the vertical line, which is proportional to the weight of the vertical ball.