在城市地铁隧道建设中，采用盾构法施工不可避免地面临始发施工场地受限、始发时间位于冬季、始发区段地表有重要建（构）筑物等施工难题。通过施工实例介绍施工期间面临以上综合施工难题时，采用盾构分体始发、对盾构刀盘开口率进行改进、增加保温棉及伴热带等冬季保温措施、选取合理的施工参数及精细化管理等针对性措施，成功完成了冬季下穿平瓦房区的分体始发施工，有效控制了房屋的沉降，确保了古旧平瓦房区房屋及居民的安全。

There are many difficulties in the shield launching for Metro tunnels in urban areas, such as difficulties related to limited site area, cold weather and sensitive buildings. During the launching of the shield for Guloudajie StationShichahai Station section on Line 8 of Beijing Metro, countermeasures, including separate shield launching, cutterhead opening ratio optimization, heat preservation, boring parameter control and accurate management, are taken. Due to the countermeasures mentioned above, successful shield launching has been achieved, the settlement of the sensitive buildings has been brought under effective control and the safety of the sensitive buildings has been guaranteed.