寒区铁路含冰率对碎石集料强度及变形特性影响试验研究  

Influence of ice content on strength and deformation characteristics of frozen ballast aggregate in cold region railway by experiments

作　　者：黎旭 严颖[2] 季顺迎[1] LI Xu;YAN Ying;JI Shunying(State Key Laboratory of Structural Analysis of Industrial Equipment,Dalian University of Technology,Dalian 116024,China;School of Civil and Safety Engineering,Dalian Jiaotong University,Dalian 116028,China)

机构地区：[1]大连理工大学工业装备结构分析国家重点实验室,辽宁大连116024 [2]大连交通大学土木与安全工程学院,辽宁大连116028

出　　处：《铁道科学与工程学报》2022年第3期697-705,共9页Journal of Railway Science and Engineering

基　　金：国家自然科学基金资助项目(11572067,11872136)。

摘　　要：在寒区冰冻条件下,道砟间的冻结现象将加剧冻结道床与轨枕、路基相互作用的复杂性,给冬季有砟轨道的安全运行带来较大挑战。为探究寒区有砟轨道中冻结道床的强度和变形特性,制备不同含冰率下碎石集料试样并进行室内低温单轴压缩试验,讨论含冰率对冻结试样应力应变曲线、强度及变形特性的影响。为表征冻结试样峰后脆性特征,定义强度衰减系数,该系数随着含冰率的增大而降低,两者关系可用幂函数表示。研究结果表明:较低加载速率下,冻结试样应力应变曲线均为应变软化型。随着含冰率的增大,曲线屈服阶段增大,峰后塑性特性增强,应变软化特征更加明显。在失效模式上随着含冰率的增大,试样由脆性破坏转为轴向劈裂的韧性破坏。高含冰率下道砟接触界面的冻结强度显著提升,会加剧冻结试样中道砟颗粒的劣化破碎行为。含冰率对力学性能有显著影响,抗压强度和有效弹性模量随含冰率的增加而增大,含冰率与抗压强度的关系可用指数函数来表示,与有效弹性模量呈近似线性关系,基于强度衰减法可估计冻结碎石料的残余强度。研究成果不仅对寒区铁路冻结道床的力学特性探究具有重要工程应用价值,也能为冰-石冻结混合体的力学行为研究提供可靠试验依据。Under freezing conditions in cold regions, the freezing phenomenon between ballast particles will intensify the complexity of interaction between ballast layer, sleeper, and subgrade, creating a greater challenge for the safe operation of ballasted track in winter. To explore the strength and deformation characteristics of frozen ballast beds in a cold region, ballast aggregate specimens with different ice contents were prepared, and a uniaxial compression test was carried out at negative temperature. The strength and deformation characteristics of frozen specimens were discussed in detail. The results show that for the low loading rate, the stress-strain curves of frozen specimens are typically strain-softening type. With the increase of ice content, the yield stage and the post-peak plasticity of the curve increases, and the strain-softening become more obvious. As the ice content increases, the failure mode of the specimen changes from brittle failure to ductile failure with axial splitting characteristics. A significant increase in the freezing strength for the contact interface of ballast increases the degradation behaviors of ballast particles. In addition, the ice content has a significant effect on the mechanical properties of the frozen specimen. The compressive strength and effective elastic modulus increase with the increasing ice content. The relationship between ice content and compressive strength can be expressed by an exponential function, while the relationship with the effective elasticity modulus is approximately linear. Finally,the strength attenuation coefficient is defined for the sake of characterizing the post-peak brittleness of frozen specimens, which decreases with the increase in ice content. Their relationship can be expressed as a power function. Based on the strength attenuation method. The residual strength of the frozen specimen can be estimated. This study not only has important engineering applications to explore the mechanical properties of ballast beds with ice in cold region

关 键 词：寒区铁路 含冰率 单轴压缩 力学性能 

分 类 号：U213.7[交通运输工程—道路与铁道工程]