1前言随着城市建设的发展,地铁下穿既有铁路的工程越来越多。为防止盾构在推进过程中,造成既有铁路区段内土体下沉,危及行车安全,同时确保隧道在列车运行荷载作用下的结构稳定,采取在推进前对铁路线路预加固和对铁路影响范围内的隧道采用加强配筋的钢纤维砼管片,以及在盾构推进时实行信息化反馈施工并进行信息分析,及时调整井下 1 Introduction With the development of urban construction, more and more subways are under existing railways. In order to prevent the shield in the process of propulsion, causing the soil in the existing railway section to sink, endangering traffic safety, and ensuring the structural stability of the tunnel under the action of train running load, pre-reinforcement of the railway line and pre-reinforcement of the railway The tunnels in the affected area should be reinforced with steel fiber reinforced concrete pipe pieces, and the information feedback construction and information analysis should be carried out while the shield is being advanced so as to timely adjust the downhole