北京地下直径线盾构独头掘进距离达5.2 km，因此隧道贯通精度控制难度大。通过测量精度分析，单纯通过导线测量已不能满足设计规定的贯通限差要求，施工中通过导线直接传递定向、洞内加测陀螺边、地上地下控制网紧密联系等辅助方法，提高了贯通横向误差的精度，达到了预期效果。

The only head driving distance of the engineering of Beijing underground diameter line is 5.2 km, thus controlling the precision of tunnel transfixion is difficult. Based on the analysis of the measuring accuracy, only through the wire line can not satisfy the design requirements of provisions error limit. Eventually, methods like wire directly orientation, adding the gyro in the tunnel and control net of wire of ground and underground in close connection are determined. These increased the lateral error precision of piercing,and achieved expected effect.