单元双块式无砟轨道道床板长度的确定

为确定双块式无砟轨道道床板的合理单元长度,采用数值模拟的方法分析了列车荷载、纵、横向荷载、温度力、温度梯度作用下不同单元长度轨道结构的应力、应变响应;在此基础上,计算了不同长度单元板的裂缝宽度及所需的最小配筋率.现场试验结果表明:单元板长度越大,内部应力、板端位移量和板中裂缝宽度越大,满足裂缝宽度限值的配筋率越大;单元双块式无砟轨道板的长度宜小于8.0 m,推荐兰新二线采用长6.5 m的单元双块式无砟轨道道床板. 

Length Determination of Track Concrete Plate for Unit Double-Block Ballastless Track

In order to determine the rational length of unit track concrete plate, the numerical simulation method was applied to analyze the stress and strain responses of unit double-block ballastless track with different lengths under train load, transversal and longitudinal loads, temperature force and temperature gradient. On the above basis, minimum reinforcement ratio needed for track concrete plate and crack widths were calculated. A contrast analysis was conducted by combining site observation. The research result shows that a long unit track concrete plate will result in high internal stresses, big plate end displacement and large crack width, as a result, the minimum reinforcement ratio needed will increase. The reasonable length of track concrete plate for unit double-block ballastless track should be less than 8.0 m, while it should be 6.5 m to subgrade sections along the new Lanzhou-Urumchi railway.