砂卵石地层盾构穿越连续梁桥加固施工技术

长沙市轨道交通1号线盾构穿越新中路立交桥D、F匝道桥梁，桥梁桩基持力层全部位于砂卵石地层，有效控制桥梁变形是盾构施工的重难点。经过比选，决定采用双液浆加固和整体式筏板承托相结合的加固方案。通过量测监控和盾构施工参数的优化控制，成功地克服了盾构穿越大型立交桥对原有结构的破坏以及对交通运行的影响。

On the Reinforcing Construction Techniques for a Continuous Girder Bridge Under-Passed by a Shield in the Stratum of Sand and Pebbles

For the construction of the No. 1 Line of the rail transit of Changsha city,the shield has to under-pass the Bridges D and F of the ring road of the flyover of the Xinzhong Road,where the force-bearing layer of the pile foundation of the bridges is completely located in the stratum of sand and pebbles, and the effective control of the deformation of the bridges is the key and difficult point in the shield construction. Through comparison and choice,the reinforcing scheme of the dual-liquid-mortar reinforcing process combined with the integral rafting slab supporting is adopted. By means of the survey monitoring and the optimized control of the construction parameters of the shield, possible damage to the original structures and the effects on the traffic operation are successfully avoided when the shield underpasses a large-type flyover.