| 饱和红层泥岩填料累积变形特性及安定界限研究 |
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| 引用本文： | 陈康,刘先峰,袁胜洋,潘申鑫,马杰,蒋关鲁.饱和红层泥岩填料累积变形特性及安定界限研究[J].岩土力学,2022,43(5):1261-1268. |
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| 作者姓名： | 陈康 刘先峰 袁胜洋 潘申鑫 马杰 蒋关鲁 |
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| 作者单位： | 1. 西南交通大学 高速铁路线路工程教育部重点实验室，四川 成都 610031；
2. 西南交通大学 土木工程学院，四川 成都 610031；3. 新疆工程学院 土木工程学院，新疆 乌鲁木齐 830023 |
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| 基金项目： | 国家自然科学基金资助项目（No.52078432,52168066）；;四川省科技计划项目（No.2019YFSY0015）~~； |
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| 摘 要： | 最优含水率下红层泥岩作为高速铁路路基填料的适用性已经在西南地区得到了初步验证，但饱和状态下红层泥岩填料的累积变形特性仍不明确。为此，开展了不同围压及动应力下饱和红层泥岩填料的动三轴试验，讨论了围压和动应力对填料累积变形特性的影响。结果表明：不同动应力幅值下，饱和红层泥岩填料的等效模量随振次增加，先迅速减小后趋于稳定。稳定后填料的等效模量具有应力水平相关性，随围压增大而增大，随动应力比增大而呈指数减小。不同动应力幅值下，填料变形可分为塑性稳定型、塑性蠕变型和增量破坏型3种类型。填料应变随振次增加而不再处于稳定阶段的应力状态定为塑性稳定界限应力状态。动应力进一步增加后，填料应变速率发生突增，对应的应力状态为塑性蠕变界限应力状态；塑性稳定与塑性蠕变界限应力状态对应的动应力比均低于静强度，且随围压增加呈指数衰减的规律。基床表层如用红层泥岩作填料，应考虑降雨的影响，并采取排水和改良措施以提高路基稳定性。
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| 关 键 词： | 红层泥岩 高速铁路 路基填料 累积变形特性 安定界限 |
| 收稿时间： | 2021-09-22 |
| 修稿时间： | 2022-02-24 |
Experimental study of accumulative deformation behaviour and
shakedown limit of saturated red mudstone fill material |
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| CHEN Kang,LIU Xian-feng,YUAN Sheng-yang,PAN Shen-xin,MA Jie,JIANG Guan-lu.Experimental study of accumulative deformation behaviour and
shakedown limit of saturated red mudstone fill material[J].Rock and Soil Mechanics,2022,43(5):1261-1268. |
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| Authors: | CHEN Kang LIU Xian-feng YUAN Sheng-yang PAN Shen-xin MA Jie JIANG Guan-lu |
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| Institution: | 1. Key Laboratory of High-Speed Railway Engineering of Ministry of Education, Southwest Jiaotong University, Chengdu, Sichuan 610031, China ;
2. School of Civil Engineering, Southwest Jiaotong University, Chengdu, Sichuan, 610031, China;
3. School of Civil Engineering, Xinjiang Institute of Engineering, Urumqi, Xinjiang, 830023, China |
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| Abstract: | Red mudstone compacted at optimal water content has been verified to be appropriate as fill material of high-speed railway subgrade. But the accumulative deformation behaviour of compacted red mudstone at saturated condition has not been investigated very well. In this study, a series of cyclic triaxial tests was carried out to study the effect of confining pressure and dynamic load on the accumulative deformation of saturated red mudstone fill (SRMF) material. Results indicate that the equivalent Young’s modulus decreases rapidly to a stable state with increasing the cyclic number. The stable is strongly correlated to the stress state, and it increases with increasing the confining pressure and decreases exponentially with increasing the cyclic stress ratio. Based on shakedown theory, three types of accumulative deformation modes, namely, plastic shakedown, plastic creep, and incremental collapse, were identified. The stress state causing the unstable deformation was named as the plastic shakedown limit. The stress state that causes a sudden increase in strain rate was defined as the plastic creep limit. The cyclic stress ratios corresponding to the plastic shakedown and plastic creep limit were smaller than the shear strength at static state, and decreased exponentially as the confining pressure increases. With particular emphasis on the effects of rainfall, the drainage facilities and improved red mudstone fill material were suggested in the design of surface layer of subgrade to enhance their stability. |
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| Keywords: | red mudstone high-speed railway subgrade fill accumulative deformation shakedown limit |
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