循环荷载作用下铁路路基级配碎石填料累积变形研究
Accumulated Deformation of Gravel Filler of Subgrade under Cyclic Loading
作者：李扬波(中南大学 土木工程学院, 湖南 长沙 410075)；张家生(中南大学 土木工程学院, 湖南 长沙 410075;中南大学 高速铁路建造技术国家工程实验室, 湖南 长沙 410075)；朱志辉(中南大学 土木工程学院, 湖南 长沙 410075;中南大学 高速铁路建造技术国家工程实验室, 湖南 长沙 410075)；王晅(中南大学 土木工程学院, 湖南 长沙 410075;中南大学 高速铁路建造技术国家工程实验室, 湖南 长沙 410075)；喻昭晟(中南大学 土木工程学院, 湖南 长沙 410075)
Author：LI Yangbo(School of Civil Eng., Central South Univ., Changsha 410075, China)；ZHANG Jiasheng(School of Civil Eng., Central South Univ., Changsha 410075, China;National Eng. Lab. for Consiuction Techol. of High Speed Railway, Central South Univ., Changsha 410075, China)；ZHU Zhihui(School of Civil Eng., Central South Univ., Changsha 410075, China;National Eng. Lab. for Consiuction Techol. of High Speed Railway, Central South Univ., Changsha 410075, China)；WANG Xuan(School of Civil Eng., Central South Univ., Changsha 410075, China;National Eng. Lab. for Consiuction Techol. of High Speed Railway, Central South Univ., Changsha 410075, China)；YU Zhaosheng(School of Civil Eng., Central South Univ., Changsha 410075, China)
收稿日期：2017-10-20 年卷（期）页码：2018,50(5):130-137
期刊名称：工程科学与技术
Journal Name：Advanced Engineering Sciences
关键字：级配碎石;大型动三轴试验;循环荷载;累积变形
Key words：graded gravel;large-scale dynamic triaxial test;cyclic loading;cumulative deformation
基金项目：国家自然科学基金资助项目（51678576；51378511；51378514）；国家重点研发计划资助项目（2017YFB1201204）；湖南省高校创新平台开放基金资助项目（13K006）
中文摘要
路基在列车往复荷载作用下会产生累积变形，引起轨道不平顺，影响列车运行的舒适性和安全性。为揭示铁路路基级配碎石填料在循环荷载作用下的累积变形规律，对级配碎石开展了大型动三轴试验，研究了循环荷载作用次数、围压及循环应力比对级配碎石累积变形的影响。试验结果表明：1）随着循环应力比的增加，级配碎石试样累积变形达到稳定所需的循环次数逐渐增加；当循环应力比一定时，围压对级配碎石试样累积变形达到稳定所需的循环次数影响不明显，围压越大，级配碎石试样最终的累积变形越大。2）相同围压条件下，循环应力比越大，级配碎石试样累积变形达到稳定所需的循环次数越多，级配碎石试样最终的累积变形越大。3）围压越大，级配碎石试样最终累积变形越大。循环应力比越大，级配碎石试样最终累积变形越大；当循环应力比达到0.4时，已不符合稳定型累积变形规律。通过试验获得了循环荷载作用次数、围压及循环应力比对级配碎石累积变形规律的影响。基于试验结果，提出了铁路路基级配碎石填料稳定型累积变形预测模型，揭示了级配碎石稳定型累积变形规律，可为准确预测和控制铁路路基工后沉降提供依据。
英文摘要
Under cyclic loading of the train, the cumulative deformation of the subgrade will be produced, which causes the track irregularity and affects the comfort and safety of the train. In this paper, the cumulative deformation of grading macadam filter for railway subgrade under cyclic loading is studied by large dynamic triaxial tests. The tests were carried out to study the effects of cyclic loading time, confining pressure and cyclic stress ratio on accumulated deformation of grading macadam material. Based on the experimental results, a mathematical model that can reflect the development pattern of the cumulative deformation of grading macadam material is proposed. The tests show: 1) With the increase of cyclic stress ratio, the number of cycles required for the cumulative deformation achieves stability increases gradually. When the cyclic stress ratio is constant, the influence of confining pressure on the number of cycles required for stability is not obvious. The larger the confining pressure is, the larger the final cumulative deformation is. 2) Under the same confining pressure, the larger the cyclic stress ratio is, the more number of cycles are needed for stability and the larger the final cumulative deformation of the grading macadam material is. 3) The larger the confining pressure is, the larger the cumulative deformation is. The larger the cycle stress ratio is, the larger the final cumulative deformation is. When the cyclic stress ratio reaches 0.4, the accumulative deformation law is no longer valid for the stable type. The influence of cyclic loading time, confining pressure and cyclic stress ratio on the cumulative deformation of grading macadam material was obtained through experiments. According to the characteristic of stable type's cumulative deformation curve, a mathematical formula for predicting the cumulative deformation of grading macadam material is proposed. The rule of stable type's cumulative deformation of grading macadam filter is revealed. It provides a basis for accurate prediction and control of post-construction settlement of railway subgrade.
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