Experimental study of temperature load determination method of bi-block ballastless track

In order to study the value determination method of temperature load on ballastless track, an eight-month temperature field test was carried out on a 10 m long bi-block ballastless track in Dabancheng. The test results showed that the ballastless track temperature and the near-surface air temperature varied periodically with the daily and annual cycles. The annual temperature extremes of ballastless track can be obtained through the air temperature extremes after the corresponding statistical temperature difference was deducted based on track slab depth. The diurnal temperature range of track slab and base plate is approximately linear to that of the surface air temperature. The diurnal temperature load on slab track can be derived from the diurnal air temperature range and the corresponding scale factor. There were gradients and lags between temperatures in slab tracks at different depths. The temperature in track slab was 2 hours behind the surface air temperature while the temperature of the base plate was about 10 hours behind every day. The temperature gradient distribution in track slab was relatively wide but extremely uneven, with 98.34% of the temperature gradient falling in -30~60℃/m range for track slab. The temperature gradient distribution in base plate was relatively narrow with 99.73% falling in the -10~20℃/m range. The temperature gradient amplitude was approximately proportional to the daily surface air temperature variation. The temperature gradient amplitude in summer was larger than in winter. © 2016, Editorial Office of Journal of the China Railway Society. All right reserved.