ANALYSIS OF WIND-SAND MOVEMENT OVER SAND DUNE WITH DIFFERENT RAILWAY FORMS DOWNSTREAM

When the railway goes through the windy desert area, the sand hazard endangers the railway engineering and normal operation of trains, and a suitable railway form design will reduce the hazard of accumulation of sand particles on railway. In this paper, taking Shashangou area of Dunhuang to Golmud railway as the research object, the multiphase flow method is used to simulate the wind sand movement over a sand dune with a railway in the reverse region, and the influence of wind sand movement on the railway subgrade engineering and bridge engineering located on the leeward slope of sand dunes is studied respectively. The main results of this work show that: The subgrade project significantly reduces the wind speed and divides the reverse area behind the sand dune into two parts, and the diversion effect of the bridge project compresses the reverse area of the leeward slope of the dune; the ballast between the tracks increases the aerodynamic roughness of the railway surface, and there is a small amount of sand deposition between tracks and a huge sand accumulations in both side of the subgrade; the complex interaction between wind field and sand particles makes the accumulated mass profiles of sand particles present non-linear relationship, the wind sweep ability for sand particles on the surface of railway grows faster than the sand accumulation ability with the increasing friction velocity in the bridge case, and this phenomenon is opposite in the subgrade case. According to the conclusion, it can be seen that the bridge engineering is better than the subgrade engineering in preventing the railway from being damaged by wind sand movement. This work offers a theoretical support for the influence of wind sand movement on railway engineering, and provides a new research thought and tool for the railway engineering design in the future.