多年冻土区青藏铁路列车荷载作用下路基振动响应研究

Vibration Response Analysis of Embankments in Permafrost Regions along the Qinghai—Tibet Railway Subjected to Train Loads

摘要:

针对多年冻土区青藏铁路列车荷载振动作用下的动稳定性，通过对北麓河和二道沟三个典型铁路路基横断面振动响应的二分量加速度观测，对比分析客运列车和货运列车引起的路基振动特性和衰减规律，研究不同防护形式路基的列车振动响应。结果表明，路基上的振动作用主要集中在40~80 Hz频率范围内；防护形式对路基的列车动力响应有明显影响，热棒加碎石路基动力响应最小，其次为碎石防护路基，未采取任何防护的路基铁轨上的动力响应最大，建议对未采取防护的路基进行防护。分析结论为青藏铁路列车作用下的路基动稳定性评估提供实测依据，对多年冻土区的路基稳定性研究提供参考。

Abstract:

To analyze the dynamic stability of embankments along the Qinghai-Tibet railway in permafrost regions under train loads, a two-component acceleration observation of vibration responses at three typical railway subgrade sections in Beiluhe and Erdaogou were performed. The vibration attenuation law and vibration characteristics of the subgrade induced by passenger trains and freight trains were analyzed and compared. The vibration response of subgrades to trains with differing protection forms are discussed. The results suggest that the frequencies of vibration on the subgrade mainly focus on the range of 40 to 80 Hz. The dynamic response of the subgrade is affected, apparently, by the subgrade protection form. The dynamic response of thermosyphon and crushed-rock subgrades is at the minimum, followed, increasingly, by the crushed-rock subgrade and the subgrade without any protection. It is therefore suggested that the subgrade should be protected. This study can provide a measured basis for dynamic stability evaluations of subgrade under train loads of the Qinghai-Tibet railway, and the conclusions can provide a reference for analyzing the dynamic stability of subgrade in permafrost regions.