| 冻胀冻融作用下材料劣化对板式无砟轨道性能的影响 |
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| 引用本文： | 闫斌,娄徐瑞利,谢浩然,陈伟,程瑞琦.冻胀冻融作用下材料劣化对板式无砟轨道性能的影响[J].交通运输工程学报,2021,21(5):62-73. |
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| 作者姓名： | 闫斌 娄徐瑞利 谢浩然 陈伟 程瑞琦 |
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| 作者单位： | 1.中南大学 土木工程学院，湖南 长沙 4100752.中国铁路设计集团有限公司，天津 300308 |
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| 基金项目： | 国家重点研发计划项目2017YFB1201204国家自然科学基金项目51608542 |
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| 摘 要： | 以哈大高速铁路路基冻胀区板式无砟轨道为研究对象，开展了快速冻融循环作用下C60、C40混凝土和砂浆材料标准立方体试件轴心受压和劈裂抗拉破坏试验，研究了冻融循环作用下材料性能劣化规律；在此基础上，建立了考虑限位凸台、环形树脂和层间黏结接触性能的CRTS Ⅰ板式无砟轨道-路基冻胀冻融空间有限元模型，研究了冻融损伤后轨道的静力特性，揭示了底座板的受力状态与损伤特征。研究结果表明:提高混凝土强度等级可显著减缓冻融循环对材料的劣化剥蚀作用，冻融循环加剧会导致结构界面接触状态显著恶化；随着冻融循环作用次数的增加，砂浆层和底座板材料性能劣化显著，弹性模量、层间黏结强度和轴心抗拉强度均大幅减小；与未冻融工况相比，300次冻融循环后，C60、C40混凝土和砂浆的峰值抗压强度降幅分别为14.7%、34.6%和29.9%，C60混凝土与砂浆胶结界面轴心抗拉强度降幅达到90.6%，C60、C40混凝土和砂浆轴心抗拉强度降幅均超过56%；在典型冻胀条件(冻胀波长为10 m，冻胀峰值为8 mm)下，冻胀中心处轨道各结构层上表面均受最大拉应力，在冻胀波脚处出现最大压应力；随着冻融循环次数的增加，轨道板和底座板所受最大拉应力亦不断增加。可见，在设计寒区板式无砟轨道时，底座板为主要控制性构件，底座板中部冻胀为最不利工况。
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| 关 键 词： | 铁道工程 板式无砟轨道 冻融循环 材料劣化 强度破坏试验 路基冻胀 |
| 收稿时间： | 2021-04-02 |
Effect of material deterioration on slab ballastless track performance under frost heaving and freezing-thawing |
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| YAN Bin,LOU Xu-rui-li,XIE Hao-ran,CHEN Wei,CHENG Rui-qi.Effect of material deterioration on slab ballastless track performance under frost heaving and freezing-thawing[J].Journal of Traffic and Transportation Engineering,2021,21(5):62-73. |
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| Authors: | YAN Bin LOU Xu-rui-li XIE Hao-ran CHEN Wei CHENG Rui-qi |
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| Affiliation: | 1.School of Civil Engineering, Central South University, Changsha 410075, Hunan, China2.China Railway Design Corporation, Tianjin 300308, China |
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| Abstract: | Taking the slab ballastless track in the frost heaving area of the Harbin-Dalian High-Speed Railway subgrade as the research object, the deterioration laws of materials properties under freezing-thawing cycles were investigated through the axial compression and splitting tensile failure tests on the standard cubic specimens of C60, C40 concrete and mortar under rapid freezing-thawing cycles. On this basis, a spatial finite element model was established for a CRTS Ⅰ slab ballastless track-subgrade frost heaving and freezing-thawing, considering the limit retaining boss, ring-shaped resin and interlayer bonding contact properties. The static properties of tracks after the freezing-thawing damage were studied, and the stress states and damage characteristics of the base plate were revealed. Research results demonstrate that the use of high strength grade concrete considerably decelerates the material deterioration and erosion due to the freezing-thawing cycle. Intense freezing-thawing cycles remarkably deteriorate the contact state of the structural interface. As the number of freezing-thawing cycle increases, the materials properties of mortar layer and base plate worsen significantly, their elastic moduli, interlayer bonding strengths, and axial tensile strengths decrease substantially. The peak compressive strengths of C60, C40 concrete and mortar decrease by 14.7%, 34.6%, and 29.9%, respectively, after 300 freezing-thawing cycles compared to those without any freezing-thawing cycles. The axial tensile strength of cementation interface between the C60 concrete and the mortar decreases by 90.6%. The axial tensile strengths of C60, C40 concrete and mortar decrease by more than 56%. Under the typical frost heaving condition (the frost heaving wave length is 10 m, and the frost heaving peak is 8 mm), the maximum tensile stress is observed at the upper surfaces of all structural layers of the track at the frost heaving center, whereas the maximum compressive stress is observed at the foot of the frost heaving wave. As the number of freezing-thawing cycle increases, the maximum tensile stresses of track slab and base plate also increase. Hence, when designing slab ballastless tracks in cold areas, the base plate is the main control component, and the frost heaving in the middle of the base plate is a highly unfavorable condition. 6 tabs, 11 figs, 32 refs. |
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