高速列车荷载下桩网结构路基竖向动应力传递分析

依托哈尔滨—大连高速铁路典型断面建立桩网结构路基有限元模型,分析路基高度和桩间距对列车荷载作用下路基竖向动应力传递的影响。研究结果表明:竖向动应力沿路堤深度逐渐减小,距桩顶同一距离的水平面上桩顶处竖向动应力最大,四桩形心处竖向动应力最小;路堤高度较小时土拱效应较弱,桩顶应力集中效应起主导作用;随着桩间距的增大土拱高度增加,竖向应力提前由衰减变为增加且单个土拱拱脚所需承担的竖向动荷载增加;计算得到的竖向动应力衰减系数在中国规范与日本规范计算结果之间。

Analysis of Pile Network Structure Subgrade Vertical Dynamic Stress Transfer Under High Speed Train Load

Based on the dynamic finite element model of roadbed with pile network structure,the influences of roadbed height and pile spacing on the vertical dynamic stress transfer of roadbed under train load and the geogrid stress were analyzed.The results show that the vertical dynamic stress decreases along with the depth of the fill.On the horizontal plane at the same distance from the pile top,the vertical dynamic stress at the pile top is the largest,and the vertical dynamic stress at the core of four piles is the smallest.The soil arching effect is weak when the fill height is low,and the stress concentration effect of pile top plays a leading role.With the increase of pile spacing,the soil arch height increases,the vertical stress changes from attenuation to increase in advance,and the vertical dynamic load of single soil arch foot increases.The attenuation coefficient of vertical dynamic stress obtained by numerical calculation is between the calculation results of Chinese and Japanese codes.