为提高地铁线路平面精调效率，避免调线后出现相邻区段控制点线位偏差，利用切圆法通过建立与圆曲线相切的辅助线进行指定角度的切圆旋转，通过协同调整交点坐标与切线方位角关系进行平面优化。结果表明： 1）在调整相邻区段线位时，切圆法可以完全不影响已稳定曲线部分的线位； 2）利用切圆法调整线位，对既有曲线的变化只是单端减短或增加圆曲线的长度； 3）在设计阶段，对于控制点众多的连续曲线区段的平面选线，切圆法具有较强的实用性； 4）在施工过程中，当发生隧道平面掘进偏移事故时，切圆法能够极大程度地提高调线的工作效率，能短时间内提出指导后续推进的调整方案，降低盾构停机所造成的工程风险。

In order to improve the plane fine adjustment efficiency of metro lines and avoid line position deviation of control point of adjacent sections after line adjustment, a tangent circle method is adopted. The results show that: 1) When adjusting the line position of the adjacent sections, the line position of the section with stable curve will not be affected. 2) By using tangent circle method, the existing curve shortens at one end and increases in length. 3) In the design phase, the tangent circle method is the most practical for plane line selection of continuous curve with plenty of control points. 4) In the construction process, by using the tangent circle method when the deviation occurs to tunnel plane excavation, subsequent line adjustment scheme can be proposed and the engineering risk induced by shield stop can be reduced.