近接桥梁大型基坑开挖及支护技术研究

Research on Excavation and Support Technology for Large Foundation Pit Near Bridges

大型形状不规则基坑开挖过程、支护结构较为复杂,施工难度大,对周边既有建筑物影响较大。依托工程实例通过数值模拟与现场实测相结合的研究方法,分析大型不规则基坑开挖对附近桥梁的影响。研究结论:基坑开挖时,围护结构变形有着明显的位置差异,基坑坑角位置处变形较小;在开挖时地连墙顶端与嵌固端位移较小,变形曲线呈现弧形。通过对比,选取了先近后远的分部开挖方法及隔离桩与隔离墙结合的支护措施,减小桥墩最大横向位移,保证了施工安全。

The excavation and support of large,irregular shape foundation pits are complex and challenging,with significant impact on surrounding structures.Using an engineering case study,this paper analyzes the influence of large-scale irregular foundation pit excavation on nearby bridges through a combination of numerical simulation and field measurement.The results indicate that during excavation,the deformation of the retaining structure varies significantly by location,with minimal deformation observed at the pit corners.The displacement between the top and embedded end of the diaphragm wall remains small,and the deformation curve exhibits an arch-like shape.Based on a comparative analysis,a partial excavation method proceeding from near to far was selected,along with a support system combining isolation piles and walls.Field measurements confirm that this construction method effectively controls the maximum lateral displacement of bridge piers,ensuring construction safety.