Numerical Analysis of Railways on Soft Soil Under Various Train Speeds

摘要

Instability and settlement of railways constructed on soft soils are among the main concerns of railway engineers. These settlements reduce the quality of the railway and its facilities and lead to financial and life losses. Therefore, several studies have shown the importance of safety in railways constructed over soft ground due to large vibrations caused by high-speed trains, especially under critical speeds. The present study was conducted to investigate the performance of railways on soft soil and the effect of its improvement using geogrid reinforcement layer in the embankment-bed contact. For this purpose, a numerical model was developed in the finite element PLAXIS software ver. 8.6 to investigate the effect of 4 train speeds (20, 80, 140, and 200 km/h) and 5 heights of the embankment (1 to 5 m) on mobilized loads on geogrid, lateral displacement of the embankment, the safety factor of the whole track, and failure surface beneath the track. The results of this study revealed that in loose beds, a large dynamic amplification occurs in ground dynamic response as the train speed reaches a critical speed which was determined in the range of 20 to 80 km/h and found that the maximum mobilized load in geogrid occurs in this speed range.