| 颗粒离散单元法动力人工边界设置方法 |
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| 引用本文： | 周兴涛,盛谦,崔臻,冷先伦,付晓东,马亚丽娜.颗粒离散单元法动力人工边界设置方法[J].岩土力学,2018,39(7):2671-2680. |
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| 作者姓名： | 周兴涛 盛谦 崔臻 冷先伦 付晓东 马亚丽娜 |
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| 作者单位： | 1. 中国科学院武汉岩土力学研究所 岩土力学与工程国家重点实验室，湖北 武汉 430071；2. 中国科学院大学，北京 100049 |
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| 基金项目： | 国家重点基础研究发展计划(973)项目(No. 2015CB057905)；国家重点研发计划(No. 2016YFC0401803)；国家自然科学基金资助项目(No.51409263，No. 11472292)。 |
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| 摘 要： | 采用颗粒离散单元法进行动力计算时，人工截断边界上需设置吸收边界条件，以防止波的反射。鉴于颗粒离散单元数值计算模型的人工边界上颗粒单元半径大小不一、边界面凸凹不平，在连续介质的黏性、黏弹性、自由场边界条件方程基础之上，推导出适用于离散介质的等效方程。在离散介质的黏性边界条件等效方程中引入微调系数，提出比值迭代法以快速确定其最优值，以实现对波的最佳吸收。采用二维颗粒离散单元计算软件PFC2D，分别建立黏性、黏弹性、自由场边界条件相关数值分析模型，探讨颗粒分布模式对黏性边界上颗粒单元半径、速度分布及比值迭代过程的影响；采用外源波动算例及经典Lamb问题算例验证黏弹性边界设置方法的正确性；通过隧洞算例检验提出的自由场边界条件设置方法的正确性。
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| 关 键 词： | 颗粒离散单元法 动力人工边界 黏性边界 黏弹性边界 自由场边界 |
| 收稿时间： | 2017-04-01 |
Dynamic artificial boundary setting methods for particle discrete element method |
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| ZHOU Xing-tao,SHENG Qian,CUI Zhen,LEN Xian-lun,FU Xiao-dong,MA Ya-li-na.Dynamic artificial boundary setting methods for particle discrete element method[J].Rock and Soil Mechanics,2018,39(7):2671-2680. |
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| Authors: | ZHOU Xing-tao SHENG Qian CUI Zhen LEN Xian-lun FU Xiao-dong MA Ya-li-na |
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| Institution: | 1. State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, Hubei 430071, China; 2. University of Chinese Academy of Sciences, Beijing 100049, China |
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| Abstract: | When dynamic time-history calculations are carried out by using the particle discrete element method (DEM), the absorption boundary condition must be applied to avoid the reflection of outward propagating waves back into the model at artificial boundaries. By considering the various radius of particle elements on the artificial boundaries and their uneven boundary surfaces, the equivalent equations for DEM is obtained based on the boundary conditions of the viscous and viscoelastic continuum and free field. Calibration factors are introduced into the equivalent equation of viscous boundary condition for DEM, and a ratio-iterative method is proposed to determine the values for optimum waves absorption quickly. Numerical models for the viscous, viscoelastic and free-field boundaries are established using the 2D particle flow code (PFC2D). We also analyze the effects of particle distribution patterns on the radius and velocity of particles on the viscous boundary and the process of the ratio-iterative method. The validity of the setting method for viscoelastic boundary condition is verified with examples of the external source problem and the Lamb problem. The free-field boundary for DEM is applied to a tunnel example for the validation. |
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| Keywords: | particle discrete element method dynamic artificial boundaries viscous boundary viscous-spring boundary free-field boundary |
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