| 基于路堤粗粒土填料力学特性的改进邓肯-张模型 |
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| 引用本文： | 何忠明,刘正夫,向达.基于路堤粗粒土填料力学特性的改进邓肯-张模型[J].中国公路学报,2023,36(1):37-46. |
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| 作者姓名： | 何忠明 刘正夫 向达 |
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| 作者单位： | 1. 长沙理工大学 交通运输工程学院, 湖南 长沙 410114;2. 中国路桥工程有限责任公司, 北京 100011 |
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| 基金项目： | 国家自然科学基金项目（51978084，51678073）；湖南省自然科学基金项目（2020JJ4605）；湖南省研究生科研创新项目（CX20200821） |
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| 摘 要： | 为研究动力及含水率变化对路堤粗粒土填料力学特性的影响，制作了不同含水率w的路堤粗粒土填料试样，先对其施加一定荷载频率f的动应力，再进行静三轴压缩试验，分析不同试样静偏应力σ0-应变ε1曲线变化规律，之后结合Janbu公式探讨动偏应力σd、w及f与参数n、K的联系，建立初始变形模量Ei、极限偏应力(σ0)ult与各控制变量的拟合公式，提出考虑动力及含水率影响的路堤粗粒土填料改进邓肯-张模型，最后开展验证试验，对比分析该改进模型的有效性。研究结果表明：三轴试验中粗粒土试样在ε1>0.5%时由弹性变形进入塑性变形阶段，不同控制因素下的σ0-ε1曲线在0.5%<ε1<2.0%范围内出现明显差异，切线变形模量Et在该范围内迅速降低，降低幅度达到58%～76%;当ε1>2%时Et变化逐渐减缓并...
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| 关 键 词： | 道路工程 本构模型 三轴试验 路堤粗粒土填料 邓肯-张模型 |
| 收稿时间： | 2021-11-08 |
Improved Duncan-Chang Model Based on Mechanical Properties of Coarse-grained Soil Filling of Embankment |
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| HE Zhong-ming,LIU Zheng-fu,XIANG Da.Improved Duncan-Chang Model Based on Mechanical Properties of Coarse-grained Soil Filling of Embankment[J].China Journal of Highway and Transport,2023,36(1):37-46. |
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| Authors: | HE Zhong-ming LIU Zheng-fu XIANG Da |
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| Affiliation: | 1. School of Traffic Transportation of Engineering, Changsha University of Science & Technology, Changsha 410114, Hunan, China;2. China Road and Bridge Engineering Co. Ltd., Beijing 100011, China |
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| Abstract: | To study the influence of dynamics and moisture content on the mechanical properties of embankment filling with coarse-grained soil, samples of coarse-grained soil under different moisture contents w were prepared. Dynamic stress with different frequencies f was applied to the samples, and then static triaxial compression tests were performed. The σ0-ε1 curves of the different samples were analyzed. According to the Janbu formula, the correlation between the dynamic deviator stress σd, moisture content w, load frequency f, and parameters n and K were explored. The fitting formulas for the initial deformation modulus Ei, ultimate deviator stress (σ0)ult, and controlled variables were established. An improved Duncan-Chang model was proposed for coarse-grained soil considering the influence of the dynamics and moisture content. Finally, verification tests were conducted to analyze the effectiveness of the revised model. The results show that the deformation of the samples changes from elastic to plastic when ε1>0.5%. Under different controlled factors, the σ0-ε1 curves of the samples change significantly in the range of 0.5%<ε1<2.0%. The tangent deformation modulus Et also changes considerably within this range; the reduction rate reaches 58%-76%. When ε1>2%, the change in Et gradually decelerates and stabilizes. The samples exhibit strain-hardening characteristics during loading. As the moisture content, dynamic deviator stress, and load frequency increase, the deviator stress decreases when it reaches the same axial strain in the static triaxial tests. The initial elastic modulus Ei of the coarse-grained soil was related to the third principal stress σ3. A linear relationship exists between lg(Ei/Pa) and lg(σ3/Pa). The parameter n in the Janbu formula is not sensitive to controlled factors. In these tests, the value of n is stable at 0.78-0.80. The relationship between σd, w, f, and parameter K is nonlinear. Parameter K decreases with an increase in σd and w, while f shows an opposite trend. The power function can be used to establish the relationship between Et and controlled factors, the relationship between (σ0)ult and controlled factors is the same. Validation tests show that the improved constitutive model in this study can effectively predict the σ0-ε1 curve of the coarse-grained soil filling of embankments with different σd, w, and f. |
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| Keywords: | road engineering constitutive model triaxial test coarse-grained soil filling of embankment Duncan-Chang model |
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