多遇地震下无砟轨道多跨简支梁桥行车安全性研究

Research on Train Operational Safety of Ballastless Track on Multi-Span Simply Supported Beam Bridges under Frequent Earthquakes

摘要:

西部地区高速铁路桥上广泛采用的无砟轨道系统具有较大的纵向刚度，而地震区亦分布广泛，震时桥上行车无可避免，针对地震下高速铁路无砟轨道桥梁桥上列车行驶的安全性，以我国西部地区常见的高速铁路多跨 CRTS II型板式无砟轨道32 m不规则简支梁桥为实际工程背景，基于WORKBENCH及SIMPACK平台建立车?线?桥一体化计算模型，研究震时不同行车速度下列车脱轨系数、轮重减载率、轮对横向力的变化规律，并提出行车安全阈值。研究结果表明：列车行驶速度越快，地震强度愈强，列车脱轨系数、轮重减载率、轮对横向力越大；考虑轨道约束作用可使列车的脱轨系数、轮重减载率、轮对横向力平均分别降低7.19%、9.96%、7.97%，其中相差最大均约为15%；轨道系统的约束作用可提高行车安全阈值，若列车运行速度为350 km/h和300 km/h时，其可承受的地震峰值加速度分别增加了22.04%、36%，当地震峰值加速度为0.2g和0.3g时，列车可安全行驶的速度分别增大了7.24%、8.14%，行驶速度的影响更大，地震来临时，应减速慢行。无砟轨道系统的约束可有效提高桥上行车安全性，在设计计算时应考虑无砟轨道系统的约束效应。

Abstract:

The ballastless track system, widely used on high-speed railway bridges in western China, has high longitudinal stiffness. Meanwhile, earthquake areas are widespread, and it is inevitable for trains to travel on bridges during earthquakes. This study focuses on train operational safety of ballast less track on bridges along high-speed railway under earthquakes. Using the CRTS II slab ballastless track on 32-meter irregular simply supported beam bridge commonly found in western China as a typi cal engineering example, an integrated vehicle-track-bridge computational model was established us ing the WORKBENCH and SIMPACK platforms. The study analyzed the variations in derailment coefficient, wheel load reduction rate, and wheelset lateral forces at different train speeds during earth quakes, and proposed safety thresholds for train operation. The results showed that as train speed and seismic intensity increased, the derailment coefficient, wheel load reduction rate, and wheelset lateral forces all increased. When the constraint effects of the track were considered, it could reduce the derail ment coefficient, wheel load reduction rate, and wheelset lateral force of the train by an average of 7.19%, 9.96%, and 7.97%, respectively, with the maximum difference being about 15%. Additional ly, the constraint effects of the track system could significantly enhance the safety thresholds for train operation. When the train ran at 350 km/h and 300 km/h, the maximum tolerable peak ground accelera tions of the train increased by 22.04% and 36%, respectively. When the peak ground accelerations were 0.2g and 0.3g, the safe train speeds increased by 7.24% and 8.14%, respectively. It could be seen that the impact of train speed was more significant, indicating that the train should slow down when an earthquake occurred. The constraint of the ballastless track system can effectively improve the train op erational safety on bridges, and the constraint effects should be considered in design calculations.