Dynamic Response Analysis Of Train-bridge Interaction System Considering Freeze-thaw Disease And Lateral Deflection Of High-speed Railway Simply Supported Beam Bridge Substructure

With the continuous development of high-speed railway in China,more and more plannings and constructions of high-speed railway will pass through the severe cold area.During the operation process of high-speed railway bridges in this area,the influence laws of seasonal freeze-thaw action on the bridge substructure deflection,strength and stability of the foundation and running performance of high-speed trains are not clear yet.The above problems have attracted broad attentions and need to explore further research.Based on the engineering background of Harbin-Dalian high-speed railway,the main research contents are studied by the methods of theoretical analysis,field tests and numerical simulation calculation.The main research work done in this dissertation includes:1.The current problems and the research status of seasonal freeze-thaw action effects on the service state of high-speed railway bridges and running performance of high-speed trains in severe cold area are reviewed,and the railway bridge substructure freeze-thaw diseases and mechanism are summarized.2.The deflection rules of high-speed railway bridge substructure under the effect of freeze-thaw action in the severe cold area are studied.Based on a multi-span simply supported beam bridge in Harbin-Dalian high-speed railway,the deflections of typical piers in river are periodically tested,and the deflections of typical piers on land are real-time monitored during the complete freeze-thaw cycle.According to the statistical data and rule analysis,the results show that:deflection rules of substructure in severe area high-speed railway bridge under freeze-thaw action have a periodic variation,and the uneven frost heaving on the bottom of pier has a great effect on the deflection of bridge substructure.3.Based on dynamic analysis theory of train-bridge interaction system,a Matlab calculation procedure is compiled,and a dynamic analysis model of train-bridge interaction system is established.The vehicle model,bridge model,track irregularity,wheel-rail interaction and solving method of dynamic equations of train-bridge interaction system are described in detail.4.The influences of bridge substructure lateral deflection and freeze-thaw disease on dynamic responses of train-bridge system and running performance of high-speed trains are studied.Based on the dynamic analysis model of train-bridge interaction system,dynamic responses of train-bridge interaction system are calculated considering different cases of bridge substructure lateral deflection and freeze-thaw disease.And the research shows:the bridge substructure lateral deflection has a significant impact on the dynamic responses of train-bridge interaction system;the stiffness deterioration on the pier base caused by freeze-thaw disease has a great influence on the bridge lateral dynamic response.