软土地区多幅高速公路下穿对高速铁路桥梁的影响研究

Study on the Impact of Multiple Highway Underpasses on High-Speed Railway Bridges in Soft Soil Area

为了研究软土地区多幅高速公路同步下穿施工对既有高速铁路造成的影响,以津秦高铁宁车沽永定新河特大桥为背景,通过Midas GTS/NX有限元软件进行数值计算,探究下穿公路桥梁施工及运营对于高铁桥墩位移的变化规律,并探究施工顺序对结果的影响。结果表明:同步施工方案的高铁桥墩位移符合规范限值要求,但竖向位移较大,超出预警值。从勘察、设计、施工、运营全过程进行风险源辨识与分析,提出相应的控制措施。分步施工对土体及高铁桥墩的扰动次数增多,导致墩顶附加位移增大,同步施工方案更优。

In order to study the influence of simultaneous construction of multiple expressways running beneath on existing high-speed railway in soft soil area,numerical calculations were conducted using the Midas GTS/NX finite element software,with the Ningchegu Yongding New River Bridge of the Jin-Qin High-Speed Railway as the background.This study explores the variation patterns of high-speed railway bridge pier displacement due to the construction and operation of the underpass highway bridges and further investigates the influence of construction sequence on the results.The results show that the pier displacement of high-speed railway bridge under synchronous construction meets the requirements of the code,but the vertical displacement is larger than the early-warning value.The risk sources are identified and analyzed throughout the entire process of investigation,design,construction and operation,and the corresponding control measures are put forward.The additional displacements on the top of the piers are increased because of the increased frequency of disturbance to the soil and the high-speed railway pier caused by the step-by-step construction.In contrast,the synchronous construction scheme is better.