Reliability of super-slope rack railway under bridge pier settlement
Reliability of super-slope rack railway under bridge pier settlement
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DOI：
10.1016/j.engstruct.2023.116751
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发表时间：
2023-11
影响因子：
5.5
通讯作者：
Zhaowei Chen;Mengqi Zhang;Lang Wang;Zhihui Chen;Shengyang Zhu
中科院分区：
文献类型：
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作者：
Zhaowei Chen;Mengqi Zhang;Lang Wang;Zhihui Chen;Shengyang Zhu
大坡度铁路经常会发生桥墩沉降，严重影响架桥系统的可靠性和稳定性。针对这一问题，考虑齿轮齿条非线性啮合特性、轮轨非线性接触特性和桥墩沉降，建立了桥墩沉降作用下的超斜坡车辆-齿条（轨道）-桥梁系统耦合动力学模型。在此基础上，研究了桥墩沉降引起的齿轮齿条系统的受力特性。讨论了两种常见的齿轮齿条连接方式（刚性连接和弹性连接）对系统适应性和安全性的动态影响。最后提出了山区铁路大坡度桥墩沉降的安全控制值。结果表明，在齿轮齿条啮合、轮轨接触等多种载荷作用下，墩柱沉降可能导致齿轮齿条紧固件断裂。当齿条与轨枕刚性连接时，当沉降量为10 mm时，扣件的最大剪应力为346.43 MPa，严重超过标准限值（235 MPa）。弹性连接时，扣件的最大剪应力为262.80 MPa，略超过极限值。齿条的结构应力远小于齿条的抗拉强度。在两种连接方式下，支架的最大变形分别为14.02 mm和11.08 mm，约为桥墩沉降量的140%和125%。机架的振动主频率分别位于70 ~ 80 Hz和65 ~ 70 Hz。桥墩沉降对扣件应力和齿条变形影响显著，对齿条轨道振动和应力影响不大。
Bridge pier settlement always occurs on the super-slope rack railway, which has serious impact on reliability and stability of rack-bridge system. Aiming at this issue, a coupled dynamic model of the super-slope vehicle-rack(track)-bridge system under pier settlement is established considering gear-rack nonlinear meshing behavior, wheel-rail nonlinear contact behavior and pier settlement. On this basis, the mechanical characteristics of gear-rack system induced by pier settlement are studied. Then, the dynamic influences of two common gear-rack connections (rigid connection and elastic connection) on the adaptability and safety of this system are discussed. Finally, the safety control value of pier settlement of the large-slope railway in mountainous areas is proposed. Results show that pier settlement potentially leads to fracture of gear-rack fasteners under multi-loads such as gear-rack meshing and wheel-rail contact. When the rack and the sleeper are rigidly connected, the maximum shear stress of the fastener is 346.43 MPa when the settlement is 10 mm, which seriously exceeds the standard limit (235 MPa). When they are elastic connected, the maximum shear stress of the fastener is 262.80 MPa, slightly exceeding the limit value. The structural stress of rack is far less than the tensile strength of rack. Under the two connection modes, the maximum deformation of the rack is 14.02 mm and 11.08 mm respectively, which is about 140% and 125% of the pier settlement. The main frequencies of the vibration of the rack are located at 70 ∼ 80 Hz and 65 ∼ 70 Hz respectively. Pier settlement has a significant effect on the stress of the fastener and the deformation of the rack, but has little effect on the vibration and stress of the rack railway.