6号对称道岔脱轨机理及影响因素

Derailment Mechanism and Influence Factors on Number 6 Symmetric Switches

编组场内使用的主型6号对称道岔发生多起脱轨事故,其安全问题一致未得到有效解决.为探索脱轨原因、提出合理应对措施,首先基于准静态轮轨接触理论分析道岔区轮轨接触特征,进而建立车辆-道岔耦合动力学模型,以车轮动态抬升量为评价指标分析车辆、轨道、道岔结构参数对爬轨性能的影响特性.结果表明:轮缘贴靠尖轨尖端时接触角仅为53°,脱轨系数临界值不足0.73,是导致6号对称道岔脱轨风险较高的根本原因;尖轨顶宽5 mm处降低值由14 mm减至10 mm、转辙角由1.1°降至0.9°、无轨撑扣件的垫板刚度由150 kN/mm降至50 kN/mm等措施,均可使得车轮抬升量保持在3 mm以下;道岔前端设置长度不小于3 m直线段、保持良好的轴箱定位状态、尖轨侧面摩擦系数保持在0.3以下也有利于防止脱轨事故发生.

Plenty of derailments in number 6 symmetric switches occur in recent years,the derailment issue has not yet been addressed successfully.In order to discover causes and put forward reasonable measurement,the wheel/rail contact feature was analyzed based on the quasi-static theory.The coupling dynamic model of train&track was built.Taking wheel uplifted height as evaluation index,the influences of vehicle and track parameters on derailment performances were analyzed.The results show that the contact angle is only 53°when the flange touches switch rail toe,the derailment coefficient criteria is less than 0.73,which is root cause of high derailment risk.The wheel lift can be kept below 3 mm by reducing the value from 14 mm to 10 mm at the top width of 5 mm,reducing the switch angle from 1.1°to 0.9°,and reducing the stiffness of the backing plate of trackless fastener from 150 kN/mm to 50 kN/mm.It is also beneficial to prevent derailment accidents by setting a straight section with a length of not less than 3 m at the front end of the turnout,keeping a good positioning state of the axle box and keeping the side friction coefficient of the sharp rail below 0.3.