地铁曲线段不规则磨耗引起的钢轨波磨监测

Monitoring of Rail Corrugation Growth Due to Irregular Wear on a Railway Metro Curve

在小半径曲线的内轨侧出现钢轨短波波磨加剧的现象,是世界上许多铁路网都面临的一个问题。由于地铁线路小半径曲线大量存在,受其影响尤为突出。本文为一实例研究,属于一个研发预测曲线地段钢轨波磨的数值工具课题的一部分。在斯德哥尔摩地铁中一处半径为120m的曲线段上,通过重复测试轨道的粗糙度及列车通过时引起的噪声,监测波磨的发展状况。在一年的打磨过程中,发生了剧烈的短波波磨,最大峰-峰值约为0.15mm。测试数据谱分析显示,在4～14cm波长范围内,粗糙度幅值较大,峰值约在5和8cm处。波磨为单一的纵向形式(波峰与轨道方向垂直),幅值在100m长的被测轨道段上呈现不规则变化。粗糙度增长速率随时间增加,直至钢轨打磨后的300天,此后仅有少量的附加粗糙度出现。由于平均车速约为30km/h,因此由波磨造成的滚动噪声主要处于200Hz以下的低频段。打磨后的139～300天,4～14cm波长范围内粗糙度级增加10.1dB,与之相应的60～200Hz频段内的滚动噪声级增加4.9dB。在干燥天气条件下,列车通过时引起人体不适的噪声主要是车轮啸鸣噪声而非滚动噪声。

Short-pitch rail corrugation developing on the low rail in sharp curves is a problem experienced by many railway networks worldwide. Because of the large existence of small radius curves,metro lines are particularly affected. This case study is performed as part of a project which aims at developing a numerical tool for prediction of rail corrugation growth on curves. The development of corrugation on a 120 m radius curve of the Stockholm metro has been monitored by repeated measurements of rail roughness and train pass-by noise. Within a grinding interval of 1 year,severe short-pitch corrugation was build up with maximum peak-to-peak magnitudes of about 0.15 mm. Spectral analysis of measurement data shows large roughness magnitudes in the wavelength interval 4~14 cm,with peaks at approximately 5 cm and 8 cm. The corrugation pattern has a pure longitudinal direction （with corrugation ridges transverse to the track direction） and an irregularly varying magnitude along the 100 m long measured track section. The roughness growth rate increased with time until 300 days after rail grinding,thereafter only moderate additional roughness growth was observed. Because of moderate train speeds of about 30 km/h,the rolling noise caused by the corrugation has a low-frequency content （200 Hz）. A 10.1 dB unit increase （139~300 days after grinding） in roughness level in the wavelength interval 4~14 cm was found to correspond to an increase in rolling noise level in the frequency interval 60~200 Hz of 4.9 dB. In dry weather conditions,discomfort related to pass-by noise is rather linked to the occurrence of wheel squealing than to rolling noise