在现行公路拱桥设计及教材中，对无铰拱弹性压缩等原因所产生的拱轴偏离，仅考虑水平方向缩短所引起的附加内力，而未计入拱轴线下降引起的附加内力，这是不全面的。通过理论分析及数值计算，对后者引起的附加内力进行了推导。一般情况下，拱轴下降所引起的影响可忽略不计，但在矢跨比很小时，需加以考虑。 In the design and teaching materials of the existing highway arch bridge, the deviation of the arch axis caused by the elastic compression of the hingeless arch only accounts for the additional internal force caused by shortening in the horizontal direction, and does not account for the additional internal force caused by the drop of the arch axis, which is not comprehensive. Through theoretical analysis and numerical calculation, the additional internal force caused by the latter is deduced. Under normal circumstances, the impact caused by the decline of the arch axis is negligible, but when the aspect ratio is small, it needs to be considered.