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考虑冻融劣化损伤的无砟轨道力学特性研究

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为研究严寒地区冻融冻胀耦合作用下的无砟轨道结构损伤机理,以季冻地区哈大高速铁路路基冻胀区为研究对象,通过开展室内快速冻融循环试验,进行标准试件轴向压缩、劈裂抗拉等破坏力学性能测试,以获取冻融循环作用后的材料状态参数.在此基础上,考虑结构材料冻融劣化状态,建立限位凸型挡台、环形凝胶树脂以及层间黏结接触特性的无砟轨道-路基冻融冻胀有限元模型,研究寒区轨道受力特性,并检算优化轨道结构配筋设计方案.研究结果表明:冻融循环劣化后,材料密实度降低,轨道结构黏结强度显著下降,底座板结构轴心抗拉强度降幅达56％以上;短波冻胀中心处轨道板及波脚处底座板界面拉应力均较大,出现脱离现象;冻融循环作用下,冻胀中心处底座板最大拉应力均超过材料轴心抗拉强度;底座板为薄弱结构,典型冻胀波长10m、峰值8 mm工况下,底座板板中冻胀为最不利情况;冻融劣化状态下,底座结构原有配筋设计不满足裂缝及钢筋屈服应力要求,严寒地区应合理加强结构配筋设计方案.
Mechanical Characteristics of Ballastless Track Considering Freeze-thaw Deterioration Damage
To study the damage mechanism of ballastless track structure under the coupling action of freeze-thaw and frost heave in severe cold regions,this paper takes the subgrade frost heave area of Harbin-Dalian HSR in seasonally frozen regions as the study object,and carries out indoor rapid freeze-thaw cycle tests to test the mechanical performance of standard specimens under axial compression and splitting tensile failure,so as to obtain the material status parameters after freeze-thaw cycle.On this basis,considering the freeze-thaw deterioration of structural materials,this paper establishes a finite element model of ballastless track-subgrade freeze-thaw and frost heave with limiting convex block,annular gel resin and interlayer bonding contact characteristics,studies the stress characteristics of track in cold regions,and calculates and optimizes the reinforcement design scheme of track structure.The study results indicate that:After freeze-thaw cycle deterioration,the material compactness decreases,the bonding strength of track structure decreases significantly,and the axial tensile strength of base plate structure decreases by more than 56％.The interface tensile stress of the track slab at the short-wave frost heave center and the base plate at the wave foot is relatively large,resulting in delamination.Under the action of freeze-thaw cycle,the maximum tensile stress of base plate at the frost heave center exceeds the axial tensile strength of materials.The base plate is a weak structure.Under the typical frost heave wavelength of 10 m and peak value of 8 mm,the frost heave in the base plate is the most unfavorable condition.Under the condition of freeze-thaw deterioration,the original reinforcement design of the base structure does not meet the requirements of cracks and yield stress of steel bars.The structural reinforcement design scheme shall be reasonably strengthened in severe cold regions.

ballastless trackfreeze-thaw cycle testmaterial deteriorationsubgrade frost heavereinforcement checking calculation

谢浩然

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中国铁路设计集团有限公司线路站场枢纽设计研究院,天津 300308

无砟轨道 冻融循环试验 材料劣化 路基冻胀 配筋检算

国家自然科学基金面上资助项目中国国家铁路集团有限公司科技研究开发计划项目中国铁路设计集团有限公司科技研究开发项目

52278470K2022G0012022A02238001

2024

10.19549/j.issn.1001-683x.2024.06.01.003

中国铁路
中国铁道科学研究院

中国铁路

北大核心
影响因子：0.407
ISSN：1001-683X
年,卷(期)：2024.(9)
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