| 引用本文: | 罗飞,张元泽,朱占元,张东杰,何俊霖.一种青藏高原冻结砂土蠕变本构模型[J].哈尔滨工业大学学报,2020,52(2):26.DOI:10.11918/201810053 |
| LUO Fei,ZHANG Yuanze,ZHU Zhanyuan,ZHANG Dongjie,HE Junlin.Creep constitutive model for frozen sand of Qinghai-Tibet Plateau[J].Journal of Harbin Institute of Technology,2020,52(2):26.DOI:10.11918/201810053 |
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| 一种青藏高原冻结砂土蠕变本构模型 |
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罗飞1,2,3,张元泽1,2,朱占元1,2,3,张东杰1,2,何俊霖1,2
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(1.四川农业大学 土木工程学院,四川 都江堰 611830; 2.村镇建设防灾减灾四川省高等学校工程研究中心, 四川 都江堰 611830; 3.冻土工程国家重点实验室(中国科学院西北生态环境资源研究院),兰州 730000)
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| 摘要: |
| 为描述青藏铁路沿线冻结砂土的蠕变特性,建立一个考虑应力和时间耦合的蠕变本构模型.首先进行一系列不同温度、干密度条件下的冻结砂土三轴蠕变试验;其次以Nishihara模型为基础,考虑应力和时间对模型元件的耦合影响,将黏弹性元件中定常的黏滞系数修正为时间和应力的函数,引入损伤变量改进黏塑性元件,构建新的冻结砂土蠕变本构模型;最后基于试验数据验证其科学性.结果表明:试验数据与拟合数据吻合良好,改进模型能较好地描述不同温度和应力水平下冻结砂土的衰减、稳态和加速蠕变特性;改进模型中黏弹性元件的黏滞系数、剪切模量和黏塑性元件的黏滞系数均随温度升高和应力水平增大而减小,损伤变量参数随着温度升高、应力水平增大而增大.成果可为冻结砂土蠕变沉降预测提供一种新的选择,为蠕变理论研究积累资料. |
| 关键词: 冻结砂土 蠕变模型 Nishihara模型 损伤变量 三轴蠕变试验 |
| DOI：10.11918/201810053 |
| 分类号:TU43 |
| 文献标识码:A |
| 基金项目:国家自然科学基金(4,3)； 四川省教育厅科研创新团队项目(16TD0006)； 中科院冻土工程国家重点实验室开放基金(SKLFSE201214) |
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| Creep constitutive model for frozen sand of Qinghai-Tibet Plateau |
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LUO Fei1,2,3,ZHANG Yuanze1,2,ZHU Zhanyuan1,2,3,ZHANG Dongjie1,2,HE Junlin1,2
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(1.College of Civil Engineering, Sichuan Agricultural University, Dujiangyan 611830, Sichuan, China; 2.Sichuan Higher Education Engineering Research Center for Disaster Prevention and Mitigation of Village Construction, Dujiangyan 611830, Sichuan, China; 3. State Key Laboratory of Frozen Soil Engineering (Northwest Institute of Eco-Environment and Resources, CAS), Lanzhou 730000, China)
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| Abstract: |
| To describe the creep characteristics of frozen sand along the Qinghai-Tibet Railway, a creep constitutive model considering the coupling of stress and time was proposed. First, the tri-axial creep tests under different negative temperatures and dry density conditions were carried out. Then, based on the Nishihara model, considering the coupling influences of time and stress on the model elements, the coefficient of viscosity in viscoelastic part was modified under the effect of time and stress, and the viscoplastic element was improved. By introducing the damage variable, an improved Nishihara model for frozen sand was proposed. Finally, the new creep model was verified based on the test results. It was found that the creep curves predicted by this model agreed well with the corresponding experimental results from low stress to high stress, and the model could describe the unsteady, steady, and accelerating creep characteristics accurately under different temperatures and stress levels. Besides, the coefficient of viscosity and shear modulus in viscoelastic part and the coefficient of viscosity in viscous plastic part decreased with the increase of temperature and shear stress, while the damage variable increased. This study could provide a new choice for the creep prediction of frozen sand, and accumulate data for the study of creep theory. |
| Key words: frozen sand creep constitutive model Nishihara model damage variable tri-axial creep tests |
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