Research On Design Of Continuous Welded Rail Track On Small Radius Curve In The Cold Area

Continuous welded rail is the key technology to guarantee operation safety of the train, improve ride comfort and reduce the cost of maintenance which has eliminated the rail joints and provides the continuous and smooth rail surface for train running. It is proved that continuous welded rail has significant advantages in technology and economy by the research and practice of laying continuos welded rail at home and abroad. In order to sovle the problems refer to the adaptability of continuous welded rail under the condition of special line type and foundation under rail in cold climate to realize the better popularization and application of continuous welded rail in cold area, this paper firstly studied the reasonable selection of key design parameters of CWR in cold area through research and analysis of domestic and foreign information and summary of field trials. On this basis, it has researched and analysed the stress and deformation characteristics, use range and strengthening measures of CWR on subgrade of small radius curve and curved bridge based on numerical simulation method. Besides, we carried out a long-term monitoring study of CWR on small radius in cold region and put forward reasonable proposals of the design and maintenance of CWR. The main research contents are as follows:(1) Research on selection of key design parameters of CWR in cold areaBased on the analysis and summary of design code and related literature of continuous welded rail, combined with field and laboratory test results, this paper puts forward suggestions of the design parameters of continuous welded rail in cold area through analyzing the influence of long-time low-temperature circumstances on the performance of railway track components of CWR (such as fastening resistance, ballast resistance or stiffness of rail pad etc.).(2) Research on design of CWR on subgrade of small radius curveThe analysis model of the stability of continuous welded rail on small radius curve of subgrade is established to analyse the stability mechanism and influence factors of continuous welded rail on curve line. It definites the use range of continuous welded rail on small radius curve in cold area and carrys out simulation analysis of the effecs of strengthen measures.(3) Research on design of CWR on curved bridgeThe three-dimensional conjunct model of track-bridge-pier of continuous welded rail track on curved bridge is established to compare the stresses and deformation characteristics of continuous welded rail track on between the curved bridge and straight bridge. Reasonable reinforcing measures of continuous welded rail track are proposed by analyzing the influence law of design parameters of CWR and the curved bridge on the stress and deformation of CWR.(4) Research on long-term monitoring technology of CWR on small radiusA long-term monitoring system for monitoring the stability of CWR (such as air temperature, rail temperature and displacements etc.) in cold regions has been developed, which has realized the long-term real-time automatic monitoring of air and rail temperature, rail lateral and longitudinal displacements and track gauge using wireless transmission technology by establishing a long-term monitoring site of the stability of CWR on small radius curve in northeast region of China. Based on analysis of the monitoring data, we can estimate and predict the stability of CWR track and put forward reasonable proposals for maintenance of CWR on small radius curve. It would provide the important guarantee for safer, more stable and comfortable operation of the railway in cold areas.