铁道建筑

针对现有道岔尖轨/心轨裂纹检监测技术现场实用性差、设备性能尚无有效验证方法等问题，通过研究60AT2钢轨中导波传播特性、最优激励模态和频率选择、传感器设计等，研制了一套基于SH(Shear Horizontal)导波的道岔断轨监测系统，并通过室内模拟伤损试验和疲劳裂纹试验开展了系统性能验证。结果表明：常规的粘贴铁块法和切割裂缝法模拟伤损不能作为验证监测系统裂纹检测灵敏度的有效手段；本文提出的监测系统疲劳裂纹检测灵敏度优于9 mm，多次试验结果显示系统能够在钢轨断裂的前两天发出预警；通过监测钢轨轨底应变和超声探伤相结合的方式能够有效地验证监测系统的裂纹检测灵敏度。

To address the issues of poor field applicability on-site of existing turnout rail and frog rail crack monitoring technologies, as well as the lack of effective methods for validating equipment performance, a broken turnout rail monitoring system based on SH(Shear Horizontal) guided waves was developed through research on the propagation characteristics of guided waves in 60 AT2 rails, optimal excitation modes and frequency selection, and sensor design. The system's performance was validated through laboratory simulations of damage and fatigue crack tests. The results show that conventional methods, such as attaching iron blocks and cutting cracks, are not effective for accurately validating the crack detection sensitivity of the monitoring system. The fatigue crack detection sensitivity of the monitoring system proposed in this paper is superior to 9 mm, and multiple test results indicate that the system can issue early warnings two days before rail breakage. The crack detection sensitivity of the monitoring system can be effectively verified by combining the monitoring of rail base strain with ultrasonic flaw detection.