重载铁路有砟轨道-路基细宏观力学行为与服役性能演变研究

Facing up to technology development needs of infrastructure design of the new heavy haul and improvement design of the existing freight railway, this proposal will study three critical issues: the interaction mechanism between the ballasted track and the subgrade; the mechanism of force transmission and interfacial failure between the ballasted track and the subgrade, and the mechanical behavior characteristics and degradation mechanism of service performance of the ballasted track-subgrade system. The numerical simulation developed to analyze the meso-macro mechanical behavior of the heavy haul ballasted track-subgrade system, using the discrete element method (DEM) and Fast Lagrangian Analysis of Continua(FLAC), the finite element method and et al. Meanwhile, the laboratory test of the ballasted track-subgrade full-scale model is also carried out. Then, the basic theory, the numerical methods and the test technology of the heavy haul ballasted track-subgrade system is developed. They will be used to reveal the mechanical behavior characteristics and the cumulative deformation laws of the ballasted track-subgrade system, the influence mechanism of th degradation ballast, the disease subgrade on the service performances of the ballasted track-subgrade system. Finally, considering the technical and structural characteristics of Chinese heavy haul railways, the design principles of the new-built heavy haul infrastructure and the improvement suggestions for the existing heavy haul infrastructure is presented in viewpoint of the mechanical behavior and service performance evolution of the ballasted track-subgrade system. This work can provide the scientific basis for the development of Chines coal railway corridors in future.

面向大轴重大运量重载铁路新线设计、既有线改造的技术需求，围绕重载铁路有砟轨道与路基相互作用和相互影响机制、轨道与路基界面动力传递与破坏机理、轨道-路基系统细宏观力学行为特征与服役性能劣化机理三个基础科学问题，采用离散单元法、快速拉格朗日差分法、有限元法等开展有砟轨道-路基系统细宏观力学行为的数值模拟分析，开展室内全尺寸有砟轨道-路基模型试验研究，建立重载铁路有砟轨道-路基力学行为分析的基础理论、数值模拟和试验研究方法，揭示重载铁路有砟轨道-路基力学行为特征与累积变形规律，探明道床劣化、基床病变对重载铁路有砟轨道-路基服役性能的影响机制与规律。最后，针对我国重载铁路结构与技术特点，从轨道-路基系统力学行为与服役性能演变的角度，提出新建重载铁路有砟轨道-路基系统设计原则，既有线有砟轨道-路基系统性能评估方法和改进建议，为中国重载铁路煤炭大通道建设提供科学依据和应用参考。

面向大轴重大运量重载铁路新线设计与既有线改造技术需求，围绕重载铁路轨道路基细宏观力学行为与服役性能演变问题，主要开展以下研究工作：1）建立了基于离散元法和快速拉格朗日差分法的轨道路基离散-连续耦合模型及其数值模拟方法，并利用室内模型试验和现场试验数据验证了理论模型与方法，为铁路有砟轨道路基结构设计研究、性能评估预测及养护维修技术开发等提供了新方法和先进的技术手段。2）开展了铁路有砟道床-路基室内实尺模型试验和朔黄重载铁路线路试验研究，获得了道床和路基累积变形规律和道砟颗粒劣化特征，通过模拟分析揭示了荷载幅值和频率对有砟道床变形的细观影响机制。3）研究了道砟颗粒刚度、道床密实度、道床厚度等对有砟轨道路基系统力学性能和动态响应的影响机制与规律，初步掌握了有砟道床-路基力学行为的基本特征，为既有重载铁路线路加固和新建重载铁路基础结构设计提供了参考。4）建立有砟轨道过渡段的离散-连续耦合计算模型，比较分析了有无楔形填充层过渡、楔形填充层材料参数、楔形填充层斜率和不同结构形式楔形填充层对过渡段各轨道部件动态响应幅值的分布情况，提出了有砟轨道过渡段结构设计与参数选取建议。本项目建立的有砟轨道路基系统离散-连续耦合计算模型及数值模拟技术具有良好的应用前景，目前已应用于轨道动力稳定新技术开发和桥上有砟轨道偏心整治技术研究。