In this paper, a dynamic model is established to investigate the dynamic behavior of train-track-subgrade-soil (TTSS) interaction. The effects of interfacial damage of the track slab induced by soil settlement on the dynamic interaction system are considered. The model framework is established by the finite element method. The soil settlement-induced track deformation is calculated by a practical iteration algorithm, where the nonlinear interfacial damage is simulated by the cohesive zone model. The simulation model is verified by comparison with other models. In regards to the excitations of the dynamic TTSS interaction system, two types of track irregularities are considered, namely the conventional track irregularities generated by known spectrums, and the additional irregularities caused by soil settlement. In the numerical study, the dynamic performances of the TTSS interaction subjected to interfacial damage, and soil settlement are compared. Next, the short wavelength irregularity is discussed as well. From the results, the vibration enhancement can be observed in the time and frequency domain. The interfacial damage of the track enhances the vibration both in low- and high-frequency domains, while the impacts of settlement are only observed in the frequency band of 0∼3 Hz. The frequency band of vibrations triggered by short wavelength irregularities is correlated with its wavelength range. Moreover, the settlement with different wavelengths and amplitudes is studied. It is shown that the increase of settlement amplitude and decrease of settlement wavelength lead to higher damage degree in amplitude and wider spatial distribution. In regards to the dynamic responses, the vehicle accelerations, wheel-rail contact forces, track displacement, and soil displacement are more sensitive to the settlement amplitudes varying from 10 to 80 mm, while the sensitive settlement wavelength is concentrated in 20 to 40 m.

中文翻译：

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不均匀沉降引起的板界面损伤下火车-轨道-路基-土动力相互作用的建模与分析


在本文中，建立了一个动力学模型来研究火车-轨道-路基-土壤（TTSS）相互作用的动态行为。考虑了土体沉降引起的轨道板界面损伤对动力相互作用系统的影响。采用有限元方法建立模型框架。土体沉降引起的轨道变形通过实用的迭代算法进行计算，其中非线性界面损伤通过粘性区模型进行模拟。通过与其他模型的比较验证了仿真模型的正确性。对于动态TTSS相互作用系统的激励，考虑两种类型的轨道不平顺，即由已知频谱产生的常规轨道不平顺和由土壤沉降引起的附加不平顺。在数值研究中，比较了 TTSS 相互作用在界面损伤和土壤沉降下的动态性能。接下来，还讨论短波长不规则性。从结果来看，可以在时域和频域观察到振动增强。轨道界面损伤增强了低频和高频域的振动，而沉降的影响仅在0∼3 Hz频段内观察到。由短波长不规则性触发的振动频带与其波长范围相关。此外，还研究了不同波长和振幅下的沉降。结果表明，沉降幅值增大、沉降波长减小，幅值损伤程度增大，空间分布更宽。 动力响应方面，车辆加速度、轮轨接触力、轨道位移和土体位移对沉降幅值10~80 mm较为敏感，而敏感沉降波长集中在20~40 m。