上跨既有线联络通道的管幕结构施工方案比选研究——以福州滨海快线火车站管幕结构施工为例

依托福州滨海快线火车站与换乘枢纽联络通道工程,提出上跨既有线管幕结构施工的分步填充砂浆方案(即方案A)和一次性填充砂浆方案(即方案B)。在ABAQUS数值分析平台上对管幕结构施工全过程展开数值模拟,重点关注既有线竖向位移和收敛及地表沉降变化规律。分析结果表明：方案A引起既有线竖向位移呈逐渐沉降趋势,方案B则呈先上浮后沉降趋势,但两套方案引起的既有线最终竖向位移大致相同;方案A和方案B引起的最终地表沉降分布规律大致相同,都呈现不规则沉降槽状,最大值位于“口”字型管幕左侧轴线处,且方案B略小于方案A。从既有线影响及施工效率等方面考量,现场采取方案B进行管幕结构施工;同时对既有线竖向位移及地表沉降展开现场监测,其量值及发展规律与数值模拟大致相同。以上研究成果可为类似管幕结构施工提供借鉴参考。

Comparative Study on the Pipe-roof Construction Scheme for Underpass Crossing Over Existing Line:Case study for the pipe roof construction in Fuzhou Binhai Express Railway Station

Based on the underpass project between Fuzhou Railway Station of Binhai Express and transfer hub, the multi-step mortar filling scheme (scheme A) and one-step mortar filling scheme (scheme B) for the construction of pipe roof crossing over existing line are proposed. The whole construction process of pipe roof is simulated on the ABAQUS platform, and the vertical displacement and convergence of the existing line and the surface settlement are well focused. The simulation results show that the vertical displacement of existing line tends to settle gradually in scheme A, while tends to float and then settle suddenly in scheme B. However, the final vertical displacement caused by the two schemes is roughly the same. The distribution of surface settlement shows an irregular trough in both two schemes. The maximum settlement is located on the left axis of box-typed pipe roof, and scheme B is slightly smaller than scheme A. Considering the influence of existing line and construction efficiency, the scheme B is adopted for the pipe roof construction on site. The field monitoring for vertical displacement of existing line and surface settlement are also conducted, and the monitoring data accord with numerical simulations roughly. These researches can provide some reference for the pipe roof construction on similar scenario.