Fu Qiang, Zheng Changjie
Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering, Hohai University, Nanjing 210098, China.
ScientificWorldJournal. 2014 Feb 26;2014:924592. doi: 10.1155/2014/924592. eCollection 2014.
A three-dimensional finite element model was developed to investigate dynamic response of track-embankment-ground system subjected to moving loads caused by high speed trains. The track-embankment-ground systems such as the sleepers, the ballast, the embankment, and the ground are represented by 8-noded solid elements. The infinite elements are used to represent the infinite boundary condition to absorb vibration waves induced by the passing of train load at the boundary. The loads were applied on the rails directly to simulate the real moving loads of trains. The effects of train speed on dynamic response of the system are considered. The effect of material parameters, especially the modulus changes of ballast and embankment, is taken into account to demonstrate the effectiveness of strengthening the ballast, embankment, and ground for mitigating system vibration in detail. The numerical results show that the model is reliable for predicting the amplitude of vibrations produced in the track-embankment-ground system by high-speed trains. Stiffening of fill under the embankment can reduce the vibration level, on the other hand, it can be realized by installing a concrete slab under the embankment. The influence of axle load on the vibration of the system is obviously lower than that of train speed.
建立了一个三维有限元模型，以研究高速列车移动荷载作用下轨道 - 路堤 - 地基系统的动力响应。轨枕、道砟、路堤和地基等轨道 - 路堤 - 地基系统由八节点实体单元表示。采用无限单元来表示无限边界条件，以吸收列车荷载通过边界时产生的振动波。荷载直接施加在轨道上，以模拟列车的实际移动荷载。考虑了列车速度对系统动力响应的影响。考虑了材料参数的影响，特别是道砟和路堤模量的变化，以详细说明加强道砟、路堤和地基对减轻系统振动的有效性。数值结果表明，该模型对于预测高速列车在轨道 - 路堤 - 地基系统中产生的振动幅度是可靠的。加强路堤下的填土可以降低振动水平，另一方面，可以通过在路堤下安装混凝土板来实现。轴重对系统振动的影响明显低于列车速度的影响。
