6号对称道岔脱轨机理及影响因素

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. 

Derailment Mechanism and Influence Factors on Number 6 Symmetric Switches

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.