Aiming at the problem of the excessive dynamic impact of wheel and rail caused by the uneven distribution of track stiffness in the turnout area of heavy haul railway,the full-size three-dimensional finite element model was established with MIDAS software for the No.12 fixed frog turnout of 75 kg · m-1 rail in its full length range to study the distribution of the overall stiffness of the track in the full length range of turnout area.Results show that the maximum stiffness of the inner rail in turnout area is 285 kN · mm-1,and the maximum difference between it and track stiffness in block section is 165 kN · mm-1.The maximum stiffness of the stock rail in turnout area is 178 kN · mm 1,and the maximum difference between it and track stiffness in block section is 57 kN · mm-1.In order to realize the homogenization of the track stiffness in turnout area,technical solution was proposed to adjust the stiffness of long heavy rubber pad under iron plate.Field tests show that the proposed scheme can reduce the maximum stiffness of the inner rail in turnout area by about 17％ and the maximum stiffness of the stock rail by about 16％.In this way,the track stiffness in turnout area is basically the same as that in block section.The inherent track stiffness irregularity in turnout area is basically eliminated and wheel-rail interaction is effectively reduced.%针对重载铁路道岔区因轨道刚度分布不均匀而造成的轮轨动力冲击作用过大的问题,运用MIDAS软件建立75 kg·m-1钢轨12号固定辙叉道岔全长范围内的三维全尺寸有限元模型,研究道岔区全长范围内轨道整体刚度的分布.结果表明:道岔区里轨刚度的最大值为285 kN·mm-1,较区间线路轨道刚度最大相差165kN·mm-1;道岔区基本轨刚度最大值为178 kN·mm-1,较区间线路轨道刚度最大相差57 kN·mm-1.为实现岔区轨道刚度的均匀化,提出调整铁垫板下长大胶垫刚度的技术解决方案.现场试验表明,该方案可以使道岔区的里轨刚度最大降低约17％,基本轨刚度最大降低约16％,实现岔区的轨道刚度基本与区间线路的轨道刚度在同一水平上,基本消除了道岔区的轨道固有刚度不平顺,有效减少了轮轨动力作用.
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