高速软基区小半径曲线箱梁施工技术

CONSTRUCTION TECHNOLOGY FOR BOX GIRDERS ON SOFT FOUNDATIONS IN SMALL RADIUS CURVES FOR HIGH-SPEED RAILWAYS

为防止桥梁建设过程中及服役期内因变形过大而发生安全事故,文中针对软基区小半径曲线连续梁施工技术开展研究。以阜溧高速大纵湖互通C匝道桥工程为背景,根据现场地质情况提出软基加固方案,建立曲线连续梁有限元模型,模拟计算自重、预应力作用下的桥梁变形情况。结果表明在桥梁施工前采用“开挖软土、换填砖渣、振动压实”方法对软基进行处理,确保现浇支架稳定。在自重作用下,软基处理后桥梁最大竖向位移仅为-10.5 mm,是软基处理前的0.51倍,最大竖向和径向位移分别出现在边跨跨中和梁体中部。为更好地控制桥梁施工质量,对桥梁变形进行监测,立模高程偏差值最大为6.5 mm,桥梁变形在控制范围内,模拟值和监测值较为接近,研究内容可为实际施工提供参考。

To prevent safety accidents caused by excessive deformation during bridge construction and service,this study focuses on the construction technology for small-radius curve continuous beams in soft soil areas.Using the C-ramp bridge project of the Fuli Expressway and Dazong Lake Interchange as a case study,a soft soil reinforcement plan was proposed based on the site's geological conditions.A finite element model of the curved continuous beam was established to simulate the deformation of the bridge under self-weight and prestress.The results indicate that pre-construction treatment of the soft soil using methods such as"excavating soft soil,replacing with brick ballast,and vibration compaction"ensures the stability of the cast-in-place supports.Under the self-weight,the maximum vertical displacement of the bridge after soft soil treatment was only-10.5 mm,which is 0.51 times of the displacement before treatment.The maximum vertical and radial displacements occurred at the mid-span of the edge spans and the middle of the beam,respectively.To better control bridge construction quality,deformation monitoring was conducted,with the maximum deviation in the formwork elevation being 6.5 mm.The bridge deformation remained within the control range,and the simulated values closely matched the monitored values.The findings of this study provide valuable reference for practical construction.