盾构在软土地层穿越既有铁路施工技术

Construction technology for Tunnel Boring Crossing underneath Existing Railway by Shield Machine in Soft Ground

上海某地铁盾构隧道穿越正在运营的沪宁铁路的咽喉区,铁路轨道对沉降控制的要求很高。采用有限元理论分析在有无旋喷桩情况下盾构穿越铁路的风险因素、提出控制沉降的技术措施:首先对盾构穿越区的地层进行了预先加固来改良地层,使地层有较好的稳定性;其次在盾构隧道设计上采用加强性管片,并增加施工预留注浆孔;在盾构穿越过程中合理配置资源,优化施工参数,加强监测和信息化管理。最后严格按方案施工,确保盾构安全顺利地穿过了沪宁铁路,为同类工程积累了经验。

A shield-bored Metro tunnel in Shanghai crosses underneath the sensitive section of Shanghai-Nanjing railway, therefore the railway authorities have strict requirements on the settlement of the railway tracks. Analysis is made on the risks of the shield tunneling across the existing railway by means of FEM and the following technical countermeasures are proposed ： firstly, pre-consolidation is made for the ground where the shield passes so as to improve the stability; secondly, strengthened segments with preserved grouting holes are adopted in the tunnel design; proper resources are allocated, the construction parameters are optimized and the construction monitoring and ground thirdly, measure- ment are enhanced; finally, the shield tunneling is executed strictly following the predetermined plan. In the end, the shield crosses underneath the existing railway successfully. The paper can provide reference for similar works in the future.