王蕴嘉, 周梦佳, 宋二祥. 考虑颗粒破碎的堆石料湿化变形特性离散元模拟研究[J]. 工程力学, 2018, 35(S1): 217-222. DOI: 10.6052/j.issn.1000-4750.2017.05.S043
引用本文: 王蕴嘉, 周梦佳, 宋二祥. 考虑颗粒破碎的堆石料湿化变形特性离散元模拟研究[J]. 工程力学, 2018, 35(S1): 217-222. DOI: 10.6052/j.issn.1000-4750.2017.05.S043
WANG Yun-jia, ZHOU Meng-jia, SONG Er-xiang. Dem simulation of wetting deformation characteristics of rockfill considering particle breakage[J]. Engineering Mechanics, 2018, 35(S1): 217-222. DOI: 10.6052/j.issn.1000-4750.2017.05.S043
Citation: WANG Yun-jia, ZHOU Meng-jia, SONG Er-xiang. Dem simulation of wetting deformation characteristics of rockfill considering particle breakage[J]. Engineering Mechanics, 2018, 35(S1): 217-222. DOI: 10.6052/j.issn.1000-4750.2017.05.S043

考虑颗粒破碎的堆石料湿化变形特性离散元模拟研究

Dem simulation of wetting deformation characteristics of rockfill considering particle breakage

  • 摘要: 堆石料广泛应用于土石坝和山区机场地基的填筑工程中,其湿化变形可能会影响工程的正常使用甚至威胁其安全性。颗粒破碎是导致湿化变形的重要原因,然而目前对于堆石料湿化过程中颗粒的破碎规律尚不明晰。该文采用离散单元法,分别模拟了侧限条件下单线法和双线法湿化变形试验,比较了单、双线法湿化变形的差异。采用Hardin破碎率表征颗粒破碎量,分析了湿化过程中颗粒破碎量与填筑体应变及颗粒间摩擦耗能等的关系。此外,还讨论了湿化路径、颗粒形状、材料软化系数对湿化变形的影响。研究结果表明:侧限条件下湿化变形随应力水平增加而增加,且单线法测得的湿化变形大于双线法。湿化路径对总变形量有一定影响,先湿化后加载可有效降低总变形量。加载过程中,颗粒破碎以棱角破碎为主,且多棱角颗粒的试样湿化变形大于浑圆颗粒试样。Hardin破碎率与试样摩擦耗能的关系受湿化路径的影响,与应变的关系不受湿化路径的影响,仅与试样初始状态和材料特性有关。

     

    Abstract: Rockfill materials are widely used in civil engineering, such as dams, railways, and airport foundations in mountain areas. Significant wetting deformation may affect the serviceability or even the safety of rockfill infrastructure. Particle breakage is an important reason for wetting deformation. However, the relation between particle breakage and wetting deformation remains unclear and further study is necessary. The discrete element method was used to simulate single-line and double-line wetting tests, and the differences between the two methods were discussed. The relationships between particle breakage characterized by Hardin index, strain and friction energy were analyzed. Furthermore, the effect of wetting path, particle shape and softening coefficient on wetting deformation were investigated. The preliminary results showed that the wetting deformation increased with the stress applied, and larger wetting deformation was observed with the single-line method. During the loading process, particle breakage mainly occurs at the corners of particles. Angular particles experience more breakages and larger wetting deformation under one-dimensional compression than rounded particles. Moreover, the relationship between the Hardin index and friction energy dissipation is affected by the wetting path, while the relation between Hardin index and the strain is unique and depends exclusively on the initial density and intrinsic parameters of the material.

     

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