本文总结了在修建15.4 km 长切内里基线隧道（CBT）期间获得的经验，这条隧道为从北向南跨越瑞士阿尔卑斯山脉的平轨铁路线的南段。该项目由直径为9 m 的双管组成，双管之间每隔325 m设置一个联络通道。在线路中部及其南端，应后勤和运营要求，开挖了大型洞室。总开挖长度大约为40 km。隧道穿越阿尔卑斯山处的岩层由各种岩石类型和若干断层带组成。最大埋深达850 m。主隧道和联络通道的开挖通过钻爆法（D&B）进行。支护由锚杆、钢筋网、纤维增强喷射混凝土和（必要时的）钢拱架构成。为开挖进口隧洞，使用了敞开式隧道掘进机（TBM）。大埋深导致岩石受到挤压，这种状况的特征为在穿越较弱岩层时产生较大的各向异性收敛。较弱岩层要求安装可变形支护。在北洞口，隧道（断面增大）穿过A2 高速公路（连接瑞士北部和南部的主要道路轴线）下方，此处埋深较小，且隧道通过的是软地层。为限制地表沉降，成功采用了垂直和近水平喷射灌浆与分部开挖相结合的方法。南洞门位于人口密集的市区。开挖自南洞门开始，包括一

This paper summarizes the experience that was gained during the construction of the 15.4 km long Ceneri Base Tunnel (CBT), which is the southern part of the flat railway line crossing the Swiss Alps from north to south. The project consisted of a twin tube with a diameter of 9 m interconnected by crosspassages, each 325 m long. In the middle of the alignment and at its southern end, large caverns were excavated for logistical and operational requirements. The total excavation length amounted to approximately 40 km. The tunnel crossed Alpine rock formations comprising a variety of rock typologies and several fault zones. The maximum overburden amounted to 850 m. The excavation of the main tunnels and of the cross-passages was executed by means of drill-and-blast (D&B) excavation. The support consisted of bolts, meshes, fiber-reinforced shotcrete and, when required, steel ribs. A gripper tunnel boring machine (TBM) was used in order to excavate the access tunnel. The high overburden caused squeezing rock conditions, which are characterized by large anisotropic convergences when crossing weaker rock formations. The latter required the installation of a deformable support. At the north portal, the tunnel (with an enlarged cross-section) passed underneath the A2 Swiss highway (the major road axis connecting the north and south of Switzerland) at a small overburden and through soft ground. Vertical and subhorizontal jet grouting in combination with partial-face excavation was successfully implemented in order to limit the surface settlements. The south portal was located in a dense urban area. The excavation from the south portal included an approximately 220 m long cut-and-cover tunnel, followed by about 300 m of D&B excavation in a bad rock formation. The very low overburden, poor rock quality, and demanding crossing with an existing road tunnel (at a vertical distance of only 4 m) required special excavation methods through reduced sectors and special blasting techniques in order to limit the blast-induced vibrations. The application of a comprehensive risk management procedure, the execution of an intensive surface survey, and the adaptability of the tunnel design to the encountered geological conditions allowed the successful completion of the excavation works.