双线铁路隧道Ⅳ级围岩深埋地段二次衬砌采用素混凝土结构的方案论证

Demonstration of a Plain Concrete Secondary Lining for a Double-Track Railway Tunnel Section in Deep-Buried Surrounding Rock of Grade IV

兰渝铁路隧道Ⅳ级围岩深埋地段采用复合式衬砌,其二次衬砌在初步设计时为钢筋混凝土结构,后经对设计参数的工程类比及隧道力学分析,将二次衬砌改为C35素混凝土结构。经过兰渝线三年的施工实践证明,二次衬砌取消钢筋后,初期支护及围岩变形在容许范围内,衬砌结构安全度达到要求,取得了预期的技术经济效益。

Composite lining was used in the deep buried section of the Lanzhou-Chongqing railway with surrounding rock of grade IV. The primary design of the secondary lining was a reinforced concrete structure. After an analog comparison of design parameters and mechanical analysis, cancelation of the reinforcement of the secondary lining was determined to be acceptable. The secondary lining was changed to C35 plain concrete in the construction plans. The implementation of the Lanzhou-Chongqing railway proved that the primary support and surrounding rock deformation were within a permissible range and the safety of the lining structure met the relative requirements for the condition of no reinforcement.