| 弹射冲击荷载下重载铁路路基动位移空间分布特征 |
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| 引用本文： | 尹紫红,朱仁政,邱泓滔,王青松.弹射冲击荷载下重载铁路路基动位移空间分布特征[J].西南交通大学学报,2021,56(4):777-784. |
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| 作者姓名： | 尹紫红 朱仁政 邱泓滔 王青松 |
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| 基金项目： | 国家重点研发计划（VP99QT136Y17001） |
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| 摘 要： | 为研究军用重载铁路路基动响应空间分布特征，通过高度非线性分析程序ANSYS/LS-DYNA3D建立了重载铁路轨道-路基-地基三维显式动力分析模型，并引入三维一致黏弹性人工边界；采用梯形冲击荷载模拟弹射冲击，探讨了不同幅值(150～600 kN)的弹射冲击荷载作用时重载铁路路基系统动位移的空间分布特征，通过Boussinesq弹性理论与林绣贤多层系统当量理论验证了数值模型的可靠性. 结果分析表明:当作用在轨道上的弹射荷载开始进入卸载状态时，路基系统的竖向动位移达到最大值；结束卸载时，道床顶面存在一定量的残余变形，且残余变形随荷载幅值增长呈线性增长，增长速率约为0.60 × 10?2 mm/kN；在不同荷载幅值下路基动位移沿线路横、纵向均呈对称分布，动位移沿竖向近似呈直线型衰减，且衰减速率随着荷载幅值的增加而增大；荷载幅值越大，路基动位移的轮对效应及道床和基床对钢轨动力的分担作用均越来越显著；路基的动位移峰值与荷载幅值大致呈线性关系，道床顶面的动位移峰值随荷载幅值增长最快，增长速率约为1.27 × 10?2 mm/kN，基床表层与基床底层次之，增长速率分别约为1.23 × 10?2、1.20 × 10?2 mm/kN，路基本体增长最慢，增长速率约为1.10 × 10?2 mm/kN.
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| 关 键 词： | 弹射冲击荷载 动位移 空间分布 显式动力分析 黏弹性边界 重载铁路路基 |
| 收稿时间： | 2019-11-16 |
Spatial Distribution Characteristics of Dynamic Displacement of Heavy-Haul Railway Subgrade System under Launching Impact Load |
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| YIN Zihong,ZHU Renzheng,QIU Hongtao,WANG Qingsong.Spatial Distribution Characteristics of Dynamic Displacement of Heavy-Haul Railway Subgrade System under Launching Impact Load[J].Journal of Southwest Jiaotong University,2021,56(4):777-784. |
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| Authors: | YIN Zihong ZHU Renzheng QIU Hongtao WANG Qingsong |
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| Abstract: | To study the spatial distribution characteristics of dynamic response of military heavy-haul railway subgrade, using highly nonlinear analysis program ANSYS/LS-DYNA3D, a 3D explicit dynamic model of a track-subgrade-foundation system was established with the 3D consistent viscous-spring artificial boundary. The trapezoidal impulse load was used to simulate the launching impact load, and spatial distribution characteristics of the dynamic displacement of the subgrade system under loads of different amplitudes (150?600 kN) were discussed. The model reliability was then verified by Boussinesq elastic theory and Lin Xiuxian?’s multi-layer system equivalent theory. The results indicated that the vertical dynamic displacement of the subgrade system reaches the maximum value when the launching impact load on the track starts to unload. At the end of unloading, there is a certain amount of residual deformation in the top surface of the ballast bed, and the residual deformation increases linearly with an increase in load amplitude, and the growth rate is about 0.6 × 10?2 mm/kN. Under different load amplitudes, the dynamic displacement of the subgrade system is distributed symmetrically both laterally and longitudinally along the line, it decays linearly along the vertical direction, and the decaying rate increases with the increase of the load amplitude. The larger the load amplitude is, the more significant the wheelset effect of dynamic displacement and the contribution of ballast bed and subgrade bed to rail dynamic force are; the peak dynamic displacement of subgrade system is approximately linear with the load amplitude. With the increase of the load amplitude, the peak dynamic displacement of the ballast bed surface grows at the fastest rate of about 1.27 × 10?2 mm/kN, followed by the peak value of the subgrade bed surface and the subgrade bed bottom at growth rates of about 1.23 × 10?2 and 1.20 × 10?2 mm/kN, respectively, and the peak value of the subgrade body grow at the slowest rate of about 1.10 × 10?2 mm/kN. |
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