| 基于离散元数值方法的砂土小应变弹性特性探讨 |
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| 引用本文： | 顾晓强,杨朔成.基于离散元数值方法的砂土小应变弹性特性探讨[J].岩土力学,2019,40(2):785-791. |
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| 作者姓名： | 顾晓强 杨朔成 |
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| 作者单位： | 1. 同济大学 地下建筑与工程系，上海 200092；2. 同济大学 岩土与地下工程教育部重点实验室，上海 200092 |
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| 基金项目： | 国家重点研发计划（No. 2016YFC0800200）；国家自然科学基金（No. 41772283；No. 51822809）；中央高校基本科研业务费。 |
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| 摘 要： | 土体在非常小应变（小于10?6）时表现为线弹性。以往大量试验研究表明，土体的弹性特性主要受到土体有效围压、孔隙比、颗粒级配和试样制备方法等影响。通过离散元方法模拟Duffy和Mindlin中的物理试验，建立球形颗粒规则排列的三维模型，继而进行小变形条件下的数值加载试验来确定弹性特性，并从细观层面揭示决定土体弹性特性的内在因素。模拟结果表明：粒状土的弹性模量取决于土体的颗粒接触配位数、法向接触力的大小和分布，跟宏观土体孔隙比、有效围压作用相对应。弹性模量应力指数n高于Hertz-Mindlin接触法则对应的1/3，主要是由于应力增加过程中配位数的增加和接触力趋于更均匀导致。同时，泊松比也随着配位数的增加而减小，并非保持不变，跟试验结果趋势一致。
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| 关 键 词： | 离散元 弹性模量 泊松比 配位数 接触力 |
| 收稿时间： | 2017-07-18 |
Numerical investigation on the elastic properties of granular soils by discrete element method |
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| GU Xiao-qiang,YANG Shuo-cheng.Numerical investigation on the elastic properties of granular soils by discrete element method[J].Rock and Soil Mechanics,2019,40(2):785-791. |
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| Authors: | GU Xiao-qiang YANG Shuo-cheng |
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| Institution: | 1. Department of Geotechnical Engineering, Tongji University, Shanghai 200092, China;
2. Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education, Tongji University, Shanghai 200092, China |
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| Abstract: | It’s well recognized that the soil response is generally linear and elastic at very small strain level (i.e. below 10-6). Previous numerous experiments showed that the soil elastic properties mainly depended on the effective confining pressure, void ratio, soil grading and sample preparation method. In this paper, the physical experiments on regular packing of steel spheres by Duffy and Mindlin were simulated by three dimensional discrete element method in order to reveal the fundamental mechanism related to soil elastic properties at meso-scale. The simulations showed that the elastic stiffness of the soil depended on the coordination number, the normal contact force and its distribution, which correspond to the macroscopic parameters of void ratio and effective confining pressure. It was found that the stress exponent n was higher than 1/3 as predicted by the Hertz-Mindlin contact model and it was mainly due to the increase of coordination number and uniformity of contact force distribution during the increase of confining pressure. Meanwhile, Poisson's ratio decreased with increasing coordination number instead of a constant as commonly assumed, which was consistent with experimental results. |
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| Keywords: | discrete element method elastic modulus Poisson’s ratio coordination number contact force |
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