本文通过用实体单元、接触单元、仅受压的杆单元、非线性弹簧单元分别模拟轨道结构、层间约束关系、桥梁对轨道的支撑及扣压型侧向挡块对轨道结构的约束，建立高速铁路简支梁桥上纵连板式无砟轨道稳定性分析模型。通过理论计算验证模型的正确性，在此基础上，比较层间约束、砂浆层切面刚度以及扣压型侧向挡块设置方式对桥上纵连板式无砟轨道稳定性的影响。研究表明：传统稳定性检算方法的基本假定与实际不符，计算结果偏于不安全；轨道结构稳定性分析需考虑实际层间非线性约束，层间约束越弱，轨道结构稳定性越差；未布置扣压型侧向挡块时，纵连板式无砟轨道结构整体温升18.9℃即失稳；轨道结构最大容许温升为30℃时，扣压型侧向挡块的间距不宜大于18.3 m ；提高砂浆层施工质量、减小挡块间距可有效提高轨道结构稳定性。%A finite element analysis model was established on the stability of longitudinally connected ballastless slab track on simply‐supported beam bridges of high speed railway .In this model ,solid finite elements were used to simulate track structure ;contact elements were applied to simulate the contact constraint relationship between adjacent layers ;compression bar elements were used to simulate the support of bridges to the track ;nonlinear spring elements were applied to simulate the constraint of pigeonhole type lateral chock blocks on track structure .The correctness of the model was verified through theoretical calculation .On the basis of this , constraints between layers ,section stiffness of mortar layer and the layout of pigeonhole type lateral chock blocks on the stability of longitudinal connected ballastless slab track were compared .The research showed that the basic assumptions of traditional stability calculating methods did not match the practical conditions ,and the caculating results tended to be unsafe .The nonlinear constraint relations between layers must be calculated during the stability analysis of the track structure .The weaker the constraint between the layers was ,the worse the stability of the track structure .The track structure lost its stability when the temperature of the lon‐gitudinally connected ballastless slab track rose to 18 .9 ℃ if pigeonhole type lateral blocks were not installed . The spacing between adjacent blocks should not be more than 18 .3m when the maximum permissible tempera‐ture of track structure was 30 ℃ .The stability of track structure can be effectively improved by improving the quality of mortar layers and reducing the spacing between adjacent blocks .
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