铁道建筑

针对大轴重条件下小半径曲线钢轨磨耗及接触疲劳伤损问题，结合钢轨现场服役条件，基于75N正偏差廓形提出面向磨耗控制的钢轨优化廓形组合1，基于75N负偏差廓形提出面向疲劳控制的钢轨优化廓形组合2；建立30 t轴重车辆-曲线轨道动力学模型并开展线路实车试验，对比分析不同廓形组合下车辆曲线通过性能、轮轨作用力、轮轨接触点分布、钢轨磨耗及疲劳发展趋势，提出2种优化廓形组合的适用性，并验证优化效果。结果表明：2种小半径曲线优化钢轨廓形组合均可满足大轴重条件下车辆安全、稳定运行要求。相较于75N与75两种标准廓形组合，优化廓形组合1的磨耗指数分别降低24.51%与11.24%，曲线上股钢轨垂向、横向力均有下降，侧磨发展趋势减小，适用于小半径曲线上股钢轨侧磨严重地段；优化廓形组合2上下股钢轨具有更优良的抗疲劳性能，有利于减缓和控制上下股疲劳伤损。

To address rail wear and contact fatigue damage on small?radius curves under heavy axle loads， two optimized rail profile combinations are proposed based on field service conditions. Combination 1， oriented toward wear control， is derived from the 75N positive deviation profile， while Combination 2， oriented toward fatigue control， is derived from the 75N negative deviation profile. A vehicle–track dynamics model for a 30 t axle load vehicle on curved track is established and field tests are conducted. The curving performance， wheel–rail forces， contact point distribution， and the evolution of rail wear and fatigue under different profile combinations are compared and analyzed. The applicability of the two optimized combinations is proposed and their effectiveness is verified. The results show that both optimized rail profile combinations for small?radius curves can satisfy the requirements for safe and stable vehicle operation under heavy axle loads. Compared with the standard 75N and 75 profile combinations， the wear index of optimized Combination 1 is reduced by 24.51% and 11.24%， respectively; the vertical and lateral forces on the high rail decrease， and the development trend of side wear is reduced， making it suitable for sections with severe side wear of the high rail on small?radius curves. Optimized Combination 2 exhibits better anti?fatigue performance for both the high and low rails， which is beneficial for mitigating and controlling fatigue damage on both rails.