Analysis Of Track-Bridge Interaction On Small Curve Radius Simply-Supported Girder Bridge & Research On Track Geometry Evolution

Under the background of railway simply supported girder bridge in small radius curve bridge,this thesis establishes a rail-fastenersleeper-ballast-grid-pier integrated spatial finite element model based on beam-plate coupled system,in view of the large track-bridge eccentric problem in several small radius curve bridges.The influence of curve radius and track-bridge eccentricity on the track-bridge interaction in small radius curve bridge are mainly explored.Meanwhile,this thesis studies the features of continuous welded rails(CWR)stability.And the features of rail stress and key factors on the curve bridge under lateral forces deprived from centrifugal force and rail-heating is investigated.The main research contents and achievements of this thesis are as follows:(1)The effects of curve radius and bridge eccentricity on trackbridge interaction of curved bridge are analyzed.The results show that,the longitudinal track-bridge interaction under the function of expansion condition and braking condition has limited effect with the change of curve radius and track-bridge eccentricity.However,opposed to deflection condition,longitudinal track-bridge interaction is be remarkably affected by the change of curve radius and track-bridge eccentricity.Therefore,the increasing effect of deflection force that comes with the decrease of curve radius and the track-bridge eccentricity to the outside of curve should be taken into consideration.(2)The characteristics of CWR stability on curved bridge are studied and compared with that on subgrade.The results show that,compared with subgrade,the stability of CWR in curve pier is obviously decrease under the function of rail-heating and centrifugal force.Meanwhile,under the function of lateral forces,the left and right rails in the curve section produce additional longitudinal rail force in the opposite direction.According to the result,the effect of centrifugal force on the CWR stability and additional longitudinal rail force is three times that of rail-heating.Thus,the effect of centrifugal force on the CWR stability analysis and study of additional longitudinal rail force can’t be ignored.(3)The influence factors of CWR stability on curved bridge are analyzed.The results show that,the influence of fastener lateral resistance and lateral and longitudinal pier stiffness on the CWR stability could be ignored.It is obviously that enlarging the ballast lateral resistance and curve radius could improve CWR stability.However,it will decrease CWR stability to a certain extent by enlarging fastening longitudinal resistance and ballast longitudinal resistance.(4)The influence factors of the additional longitudinal rail force on curved bridge under the function of transverse force are studied.The results show that,the fastener lateral resistance and ballast lateral resistance and lateral pier stiffness have little influence on the additional longitudinal rail force on curved bridge under the function of transverse force.On the contrary,the longitudinal pier stiffness and fastener longitudinal resistance and ballast longitudinal resistance and curve radius have great influence on the additional longitudinal rail force on curved bridge under the function of transverse force.