The motion characteristics of wind-blown sand flow around the railway embankment were simulated by the FLENT eulerian two-fluid model,and the simulation results were compared with field surveys.Results show that the model can well simulate the motion characteristics of wind-blown sand flow around the railway embankment,and the numerical simulation is in conformity with field investigations.Numerical simulation a-nalysis shows as follows:Air velocities surrounding the embankment produce partitioned area,i.e.,the decel-eration area,acceleration area,high-speed area,low-speed area and turbulent area;sand speeds and wind speeds influence one another,forming a feedback mechanism;in the transition zone,when the wind speed is greater than the initial sand speed,the velocity of sand grain is positively correlated with the wind speed;the formation mechanism that the sand sediment on the windward slope is more than on the leeward slope is re-vealed under the condition of the single orthogonal wind direction;sand sediment on the top of the embankment is in normal distribution,more in the middle and less on both sides;as the wind speed raizes,windward slope sediment decreases whereas leeward slope sediment has no obvious changes;different ground surface conditions have significant effects on the sand flow density and structure,thus determining the engineering sand preven-tion measures to be taken.%基于 FLENT欧拉双流体模型，对路堤周围风沙两相流运动特性进行数值模拟，并将模拟结果与现场实际调查进行比较。结果表明，所用模型能较好地模拟路堤周围风沙两相流的运动特性，数值模拟与现场调查相吻合。数值模拟分析表明：路堤周围气流速度产生分区，分别形成减速区、加速区、高速区、低速区与紊流区；沙粒速度与风速相互影响，形成一种反馈机制；在过渡区内，当风速大于起沙风速时，沙粒速度与风速呈正相关；正交单向来风条件下，揭示了迎风坡积沙量大于背风坡的形成机理；路堤顶面积沙量呈“正态形”分布，中间多，两边少；迎风坡积沙量随着风速增大而减小，背风坡无明显变化；不同地表条件对风沙流密度及结构影响显著，决定着工程防沙措施。
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