大直径泥水盾构始发段掘进对近接既有地铁桥梁的影响分析

为了在大直径盾构泥水始发段保障邻近既有地铁桥梁结构的安全性和正常营运,依托京张高铁清华园隧道3#～2#盾构区间始发段施工工程,采用有限元方法建立三维精细化数值模型,分析始发段大直径盾构掘进引起邻近桥梁结构的变形规律,并给出有针对性的防护措施.研究结果表明:在大直径盾构始发施工时,在不采取防护措施的情况下,盾构工程对邻近...

Analysis on influence of large-diameter slurry shield tunneling in launching section on adjacent existing metro bridges

In order to ensure the safety and normal operation of the adjacent existing subway bridge structure in the launching section of large-diameter slurry shield tunneling,the safe tunneling in the launching section of shield is crucial.Based on the construction engineering in the launching section of the 3~2# shield section of Tsinghuayuan Tunnel of Beijing-Zhangjiakou High Speed Railway,a three-dimensional refinement numerical model was established by the finite element method.The deformation law of adjacent bridge structure caused by large-diameter shield tunneling in the launching section was analyzed,and the targeted protective measures were given.The results showed that the shield tunneling had great impact on the adjacent bridge structure without protective measures in the launching construction of large-diameter shield.The horizontal transverse displacement of bridge structure caused by shield tunneling was much higher than the horizontal longitudinal displacement,and both the deformation of pile foundation and pier near the tunnel side were higher than that at the far tunnel side,so the protective measures should be taken for adjacent bridges in two stages of shield approaching and far away.The comprehensive utilization of stratum reinforcement,barrier protection and dynamic monitoring technology can effectively protect bridge structure,which can provide reliable reference for similar projects in the future.