Line C of Rome underground will cross the city from southeast to northwest, with a total length of about 25 km, passing through the historical city centre. This is a difficult environment due to many archaeological finds and pre-existing buildings of great historical value. Along stretch T3 of the line two conventional tunnels connect the TBMs launching pit to the new San Giovanni station. They run for a length of 140 m at a depth of about 25 m and reach the station passing at a short distance from the ancient Aurelian Walls (3rd century CE). Excavation of these tunnels was carried out following a three-stage procedure: (i) excavation of two small diameter tunnels (D = 3 m) using a mini slurry shield machine; (ii) soil improvement via cement grouting using tubes à manchettes installed radially from the mini-tunnels; and (iii) conventional excavation of the two running tunnels in the improved soil. An extensive monitoring system was set to control ground movements induced throughout the excavation process.

中文翻译：

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土壤改良对常规隧道施工地表移动的影响


罗马地铁 C 线将从东南向西北穿过城市，全长约 25 公里，途经历史悠久的市中心。由于许多考古发现和具有重要历史价值的预先存在的建筑，这是一个困难的环境。沿着线路的 T3 路段，两条常规隧道将隧道掘进机始发坑与新的 San Giovanni 站连接起来。它们全长 140 m，深度约为 25 m，到达车站时，距离古老的奥勒良城墙（公元 3 世纪）不远。这些隧道的挖掘工作分三个阶段进行：（i） 使用小型泥水盾构机挖掘两条小直径隧道 （D = 3 m）;（ii） 使用从小型隧道径向安装的管子通过水泥灌浆改良土壤;及 （iii） 在改良土壤中对两条运行隧道进行常规挖掘。设置了一个广泛的监控系统来控制整个挖掘过程中引起的地面移动。