A fatigue model for track-bed materials with consideration of the effect of coarse grain content. (June 2020) - Su, Yu
Abstract: Previous studies showed that the permanent strain of interlayer soil in the French conventional railway substructure is highly dependent on the volumetric coarse grain content f v (volumetric ratio of coarse grain to total sample). This study developed a fatigue model allowing the effects of coarse grain content f v, stress state and number of loading cycles N on permanent strain to be accounted for. Data from the multi-stage loading cyclic tests of interlayer soil conducted at six different f v values (0%, 5%, 10%, 20%, 35% and 45%) and five different maximum deviator stress Δ q max values (10 kPa, 15 kPa, 20 kPa, 25 kPa and 30 kPa) were reviewed and used for this purpose. The model parameters were determined by fitting the results from the tests at f v = 0%, 5% and 35%. In order to validate the proposed fatigue model, the determined model parameters were then used to simulate the tests at f v = 10%, 20% and 45%. The results obtained showed that the proposed model can well describe the permanent strain after a certain number of loading cycles, in the case of plastic shakedown.