某公路和水渠下穿既有高铁桥梁影响分析

Influence Analysis of the Highway and Canal Crossing Underneath Existing High-Speed Railway Bridge

某公路和水渠下穿既有京沪高铁桥梁,交叉处地面挖深较大,下穿高铁处均采用防护桩支护后顶进U型槽的方案。建立有限元模型对施工过程进行影响分析,结果显示:预制U型槽基坑布置于高速铁路影响区外;施工中高铁桥梁墩顶竖向、纵向和横向的最大附加位移值分别为1.49、0.99和0.75 mm,U型槽顶进至桥下设计位置时对桥梁墩顶竖向位移的影响最大;工程实施对桥梁桩基承载力的累计影响小于原设计单桩容许承载力;分析结果满足《公路与市政工程下穿高速铁路技术规程》的相关要求。

The highway and canal cross underneath the existing Beijing-Shanghai High-Speed Railway bridge.The scheme of using fender piles for support and then jacking into U-shaped grooves is adopted due to the large ground excavation depth at the intersection.The finite element model is established to analyze the influence of the construction process.The results show that:The prefabricated U-shaped groove foundation pit is arranged outside influence area of the high-speed railway;the maximum additional displacement values for the vertical,longitudinal,and transverse directions of pier top of the high-speed railway bridges during construction are 1.49 mm,0.99 mm,and 0.75 mm,respectively.The U-shaped groove has the greatest influence on the vertical displacement of the pier top when it is pushed into the design position under the bridge.The cumulative impact of engineering implementation on the bearing capacity of bridge pile foundations is less than the allowable value.The analysis results meet the requirements of the Technical Specification for Highway and Municipal Engineering Undercrossing High Speed Railway.