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投稿时间：2020-03-21 修订日期：2020-10-11
投稿时间：2020-03-21 修订日期：2020-10-11
中文摘要: 堰塞体是由崩塌、滑坡、泥石流、冰碛等形成的结构松散的堆积体，且多由宽级配无黏性土组成，易在上游水位抬升过程中产生渗透破坏，从而导致溃决，对下游居民财产与生命安全造成严重威胁。基于离散元和流体动力学（CFD–DEM）相耦合的数值模拟方法是研究堰塞体渗透破坏过程及颗粒冲蚀规律等的有力工具，但CFD–DEM耦合计算方法需要不断地交互计算及数据传递，导致计算量大，计算速度较慢。基于堰塞体颗粒材料在渗透破坏过程中的受力特征，在分析渗透破坏过程中流体对颗粒作用力的基础上，利用加速度场与拖曳力的简化形式表征流场作用力，提出一种简化的渗透破坏离散元快速模拟方法。该方法可以将堰塞体颗粒在渗流场中所受的作用力，直接以加速度场的方式施加在DEM模块中，减少了传统CFD–DEM耦合方法中的双模块交互迭代所需要的计算量，从而在保留CFD–DEM耦合方法计算效果的基础上，有效提升计算效率。最后，针对宽级配无黏性堰塞体土料，利用简化后的理想不连续级配颗粒模型，对比CFD–DEM耦合方法计算结果，对本文所提出的快速模拟方法的合理性和有效性进行了验证。结果表明：在试样细颗粒流失量随运行时步的变化值与变化趋势方面，简化模拟方法与CFD–DEM耦合方法基本一致，流失量误差不超过3.4%，这表明了本文所提简化模拟方法的可靠性；当对某一具体的堰塞体颗粒采取简化模拟方法进行模拟时，误差的具体量值可能会发生变化。计算速度方面，快速模拟方法在本文模拟中的运行速度约为CFD–DEM耦合模拟方法的3.5倍，且当颗粒数量越多时，简化模拟方法的计算速度提升越明显。
Abstract:The barrier dams are loose accumulation bodies formed by collapse, landslide, debris flow or moraine, and most of them are composed of loosely and widely graded cohesionless soil. The barrier dams are susceptible to internal erosion during the rapid rising of upstream water level, and threaten the downstream residents’ property and life safety. CFD–DEM coupling approach is often used to model the internal erosion of barrier dam, but it often costs lots of time due to the coupling counting and corresponding data processing. Based on the encountered forces of cohesionless soils of barrier dams during the process of seepage failure, the fluid force applied to the particles was analyzed and a simplified method to modeling the internal erosion process with the discrete element method was suggested. Utilizing this method, the encountered fluid force of a particle in the flow field was applied to the DEM module in the form of an acceleration field. Then, the amount of calculation required for the dual-module interactive iteration in the traditional CFD–DEM coupling method could be reduced, and it could effectively improve the calculation efficiency based on retaining the calculation effect of the CFD–DEM coupling method. Finally, pointing at the wide-graded non-cohesive dam soil materials, the simplified ideal gap-graded sized particle model was used to compare the CFD–DEM coupling calculation results to verify the rationality and effectiveness of the fast calculation method proposed in this paper. It showed that the relative error was within 3.4%, which proved the reliability of the simplified simulation method. When a simplified simulation method was adopted to simulate specific cases, the specific magnitude of the error might change. In terms of calculation speed, the running speed of the fast simulation method in this simulation was approximately 3.5 times than that of the CFD–DEM coupled simulation method, and when the number of particles increased, the calculation speed of the simplified simulation method increased significantly.
keywords: landslide dam granular material internal erosion discrete element method numerical simulation
文章编号：202000211 中图分类号： 文献标志码：
基金项目:国家重点研发计划项目（2018YFC1505004）
| 作者 | 单位 | |
| 李维朝 | 中国水利水电科学研究院 流域水循环模拟与调控国家重点实验室，北京 100038 | liwc@iwhr.com |
| 仲琦 | 中国水利水电科学研究院 流域水循环模拟与调控国家重点实验室，北京 100038 | |
| 楚一帆 | 中国地质大学（北京）工程技术学院，北京 100083 | |
| 李少朋 | 中国电建集团 北京勘测设计研究院有限公司，北京 100024 |
作者简介:李维朝(1979-),男,教授级高级工程师,博士.研究方向:土石坝、地质灾害和环境岩土.E-mail:liwc@iwhr.com
引用文本：
李维朝,仲琦,楚一帆,李少朋.基于加速度场的堰塞体颗粒材料渗透破坏离散元快速模拟方法[J].工程科学与技术,2020,52(6):75-82.
LI Weichao,ZHONG Qi,CHU Yifan,LI Shaopeng.Fast DEM Modelling Approach for Internal Erosion of Barrier Dam Granular Materials Based on Acceleration Field[J].Advanced Engineering Sciences,2020,52(6):75-82.
引用文本：
李维朝,仲琦,楚一帆,李少朋.基于加速度场的堰塞体颗粒材料渗透破坏离散元快速模拟方法[J].工程科学与技术,2020,52(6):75-82.
LI Weichao,ZHONG Qi,CHU Yifan,LI Shaopeng.Fast DEM Modelling Approach for Internal Erosion of Barrier Dam Granular Materials Based on Acceleration Field[J].Advanced Engineering Sciences,2020,52(6):75-82.