基于离散元法的散体道床与基床表层耦合变形机理研究

Mechanism of ballast bed-bedding surface coupled deformation based on DEM

基于真实道砟颗粒外形,采用离散元法建立了能真实模拟道砟颗粒间、道床与轨排之间、道床与基床表层之间耦合作用机理的轨枕-道床-基床表层精细化耦合模型。基于验证后的模型,对高速运营条件下轨道结构受力特性、弹性和塑性变形机理以及轨道沉降中道床和路基沉降所占比例进行深入研究。结果表明:轨道内接触力呈锥台状向下传递,在锥台形状断层处以斜面形式向斜下方延伸;存在道砟与基床表层碎石相互入侵现象,轨道沉降中道床沉降所占比例为83.9%~86.8%;轨道垂向弹性和塑性变形量、轨道沉降中道床沉降所占比例均会随着行车速度、列车轴重的增大而非线性增加。

A sleeper-ballast-bedding surface coupled model was established with DEM to simulate the coupled action mechanism of ballast-ballast,ballast-sleeper,and ballast-bedding surface based on realistic appearance of ballast.The track structure loads-bearing characteristics,elastic and plastic deformation mechanism,and ballast bed/bedding surface’s proportion under the condition of high-speed operation were studied deeply based on the model verified.The results showed that the track contact force shaped like a frustum is passed down,it extends below the syncline as a bevel;there are mutual invason phenomena of ballast-bedding surface,the proportion of ballast bed settlement is 83.9%-86.8%;track vertical elastic and plastic deformations and the proportion of ballast bed settlement increase nonlinearly with increase in train speed and train axle loads;the effects of train speed on track vertical deformation exceed those of train axle loads.