夏季桥上CRTS I型双块式无砟轨道温度梯度研究
Study on temperature gradient of CRTS I twin-block ballastless track on bridge in summer

摘要 通过对我国东南地区某简支梁桥上CRTS I 型双块式无砟轨道结构温度场的持续监测，重点研究了夏季高温下轨道结构温度梯度分布规律，采用高阶矩法建立了轨道结构夏季温度及温差概率统计模型，确定了具有一定重现期的轨道结构温度与温差代表值，提出适用于我国东南地区CRTS I型双块式无砟轨道结构的夏季横、竖向温度梯度拟合模式.试验研究表明：夏季轨道中部从上至下对应超越概率0.01的高温代表值依次为47.7 ℃、40.1 ℃、36.9 ℃与35.8 ℃；晴天温度梯度分布均匀，轨道结构横、竖向分别于17:00、15:00达到最大，温差可达6.7 ℃、12.2 ℃；竖向和横向对应超越概率0.01的正负温差代表值分别为16.16 ℃、-6.32 ℃与7.75 ℃、-4.43 ℃；竖向正负温差代表值采用指数形式进行拟合，其分布规律与中国铁路桥梁规范相近，横向正负温差代表值可采用折线形式进行拟合，精度较高.
Abstract：The regular distribution of temperature gradient of track structure under high temperature in summer are analyzed in detail through the continuous temperature field monitoring of CRTS I twin-block ballastless track on simple supported beam bridge in Southeast China. The statistical probability models of temperatures and temperature differences of track structure in summer are established by higher moment method, which have ascertained the representative values of temperatures and temperature differences of track structure with a certain return period, and the transverse and vertical temperature fitting module of twin-block ballastless track in southeastern China have been put forward. The analysis results have revealed that the representative values of high temperature are 47.7 ℃, 40.1 ℃, 36.9 ℃ and 35.8 ℃ from top to bottom in the middle of track in summer with the exceedance probability of 0.01. The temperature gradient distributions of track structure are uniform in sunshine, and the maximum positive gradientfrom the transverse and vertical point reaches in 17:00 and 15:00, with the temperature reaching 6.7 ℃ and 12.2 ℃ respectively. The positive and negative representative values between the vertical and the transverse base are 16.16 ℃, -6.32 ℃ and 7.75 ℃, -4.43 ℃ respectively with the exceedance probability of 0.01, and the vertical positive and negative representative values are fitted by the exponential form, which is approached to the temperature load modes of the concrete box girder in Chinese railway bridge code. The transverse positive and negative representative values are fitted by the polyline with higher accuracy.