高铁长期荷载作用下路基不均匀冻胀的演化及影响

Evolution and Impact of Non-Uniform Frost Heave of Subgrade under Long-Term Load of High-Speed Railway

摘要: 目的：在季节冻土区，高铁线路路基产生非均匀冻胀几乎难以杜绝；列车长期循环通过时，冻胀区土体变形会持续发展，进而波及行车平稳性与轨道长期使用性能。方法：将车辆–轨道耦合动力学计算同土体累积塑性应变预测模型相衔接，建立一种面向列车循环荷载的路基冻胀变形及车轨耦合系统动力性能演化分析方法，并选取实际线路稳定冻胀阶段进行算例研究。结果：分析表明，该方法可立足于车–轨–路协同作用，刻画循环荷载下非均匀冻胀的演化过程，并同步反映线路几何形位变化时上部车辆–轨道系统动力指标的演变趋势。结论：在列车荷载长期反复施加后，路基非均匀冻胀所诱发的轮轨瞬时动力冲击和层间界面接触劣化会有所减轻。因此，累积行车荷载对缓解路基冻胀引起的轨道几何不平顺具有有利影响。

Abstract: Objective: In seasonally frozen regions, non-uniform frost heave of high-speed railway subgrades is nearly unavoidable. Under long-term cyclic train loading, the deformation evolution within frost-heave zones directly influences vehicle running quality and track service performance. Method: By integrating a vehicle-track coupled dynamics model with a soil cumulative plastic strain prediction model, this study develops a prediction method for evaluating subgrade frost-heave deformation and the evolution of dynamic performance of the vehicle-track coupled system under cyclic train loading. A case study is further conducted based on the stable frost-heave period of an actual railway line. Result: The results show that the proposed method can describe the development of non-uniform frost heave under cyclic loading from the perspective of vehicle-track-subgrade interaction, while simultaneously capturing the evolution characteristics of the dynamic performance of the vehicle-track system above the subgrade as track geometry varies. Conclusion: The long-term application of train loads alleviates, to a certain extent, the transient wheel-rail dynamic effects and interlayer contact deterioration caused by non-uniform subgrade frost heave. Therefore, cumulative traffic loading exerts a positive influence on reducing track irregularities induced by subgrade frost heave.