Research On The Influence Of New Highway Under-Crossing Existing High-speed Railway Bridge

In recent years, with the rapid development of highway and high-speed railway in our country, the highway and railway crossing is the inevitable form in the construction. As the proportion of bridge is high in the high-speed railway, it’s more and more common for the new highway under-crossing the existing high-speed railway bridge. Whether using cutting excavation or filling embankment, the new highway construction will have some impact on the existing high-speed railway bridge. Based on the common simply supported-girder-bridge in the high-speed railway, the research on the influence of new highway under-crossing existing high-speed railway bridge is carried out including the following contents:(1) Relying on the actual situation of the new bridge in the expansion project of Jin Wen and the adjacent existing bridge, the site monitoring of ground soil stress caused by cap excavation was carried out. The cap excavation finite element model was established by large general finite element software ABAQUS. The change of ground soil stress in the excavation construction was simulated and contrasted to the site monitoring results.(2) The cutting excavation and the filling embankment were simulated to study the impact of new highway construction on the existing high-speed railway bridge. In the research, the different cutting excavation depth, the different cutting excavation width, the different filling embankment height and the different filling embankment width were discussed. The calculating data and standard limiting value were contrasted.(3) Under the special conditions such as rainstorm, soil lateral-load and local preload in the new highway construction, the influence of existing high-speed bridge settlement and deformation were analyzed, which can provide meaningful reference for the construction scheme and emergency plan of similar construction.(4) In the operation period after the completion of the highway, the influence of normal vehicle load and vehicle overload on the existing high-speed railway bridge was analyzed. The calculating data and standard limiting value were contrasted.(5) The impact on existing high-speed bridge line status caused by new highway was analyzed. From the aspects of design, construction and site monitoring, the measures and methods of reducing the influence of the new highway project on the existing high-speed railway bridge were discussed.