Experimental Study on Temperature and Lateral Deformation of Rail at the Transition between Bridges and Tunnels

Abstract

Research purposes: In recent years, according to on-site observation, it is found that CWR in ballastless track will produce lateral deformation in sporadic bending form. For high speed railway, it is easy to stimulate hunting motion of locomotive and rolling stock and has a great im pact on driving stability, comfort and safety. Through carrying on monitoring experiment on late ral deformation of rail on ballastless track, the time- dependent property of lateral deformation of rail will be obtained, which attaches great significance to revealing the mechanism of lateral deformation of rail and ensuring the stability of the ballastless track lines, as well as safety and comfort of driving. In troduction Our country applies a large number of high-speed railway CWR in Ballastless track. The fastening system of ballastless track is directly connected with the concrete bed, compared with the ballast tra ck, the stability of ballastless track is better and has enough vertical and horizontal resistance, which is generally considered to be away from track buckling accidents and not to check its stability (1-6). And the ballastless track stability theory at home and abroad is short of systematic research (7). But under special foundation conditions, such as the transition section between bridge and tunnel, due to be comprehensively affected by the train random loading, initial irregularity of rail and lateral expansion of bridge or other factors, the geometry state of the track changes relatively fr equently, which plays a crucial role on the safety of the whole line and the quality of its ope ration.In August 2007, China Academy of Railway Sciences surveyed geometry state of the track(gauge and track alignment) of Jialing River Bridge, the Jiangjia bridge and Mu Yukou tunnel on the Suiyu line, three abnormal geometry state of the track was measured in the mouth of the tunnel and transition between road and bridge with the rail irregularity of the gauge deviation of 2.0~2.5mm and sporadic bending wavelength of 4m(8,9). Study on basic characteristics and va riation rules of track geometry state at transition section with scientific and comprehensive e valuation of track geometry state attach great scientific research value and engineering significance to revealing the sporadic bending phenomenon and the guidance of track maintenance for ba llastless track CWR in high-speed railway.