Construction Monitoring And Deformation Characteristic Analysis Of Skew Frame Bridge Underpass Heavy Haul Railway

In recent years,the number of the construction of crossing the heavy haul railway is increasing.The the heavy haul railway has large axle load and volume,so the incremental launching construction is difficult It is of great practical significance to study the stability of track,frame bridge and reinforced structure under different working conditions in construction.Based on the project of Jinshi Expressway crossing Shuohuang Railway,this thesis comprehensively analyzes the stress and deformation characteristics of each construction structure,and optimizes the control measures of track deformation.The main work of this thesis is as follows:(1)Reasonable arrangement of measurement points.The monitoring data of the track geometry during the incremental launching construction are summarized and analyzed.A finite element model of the incremental launching construction is established.After comparison,the simulation value of the settlement of the track has a high coincidence with the measured value,and the model can accurately reflect the actual situation of construction.(2)Based on the finite element model,the article define four train loads.The deformation law of the track,frame bridge,reinforcement system and pile group is studied.The characteristics of structural deformation under various working conditions are similar,and the large axle load has less impact on the force deformation of the pile group and the frame bridge,and has a greater impact on rail settlement and steel beam deflection.(3)The vertical displacement of the track is characterized by a "U" shape,and the track settlement will increase sharply when the frame bridge crosses the railway.The frame bridge mid-span has the greatest deflection in contact with the soil,and the deflection value of the top plate of the acute angle side of the diagonal frame bridge is greater than that of the obtuse angle side.The horizontal deformation of the pile group is cantilever-shaped,the maximum horizontal displacement occurs at the top of the piles,and the maximum horizontal displacement is accumulated with the during construction.The horizontal displacement of the piles near the acute angle side is greater than that of the obtuse angle side.(4)Compared to the speed,the length of excavation length has a greater impact on the track settlement.The train speed increased by 10 km/h,the track settlement increased by 4.14%,the length of excavation length increased by 0.5 m,and the track settlement increased by 23.65%.The maximum length of the project should not exceed 1.5m,and the train speed should be limited to 50km/h.