关岩鹏, 梁涛, 刘晓红, 等. 2022. 掘削卵砾石地层颗粒离散元模拟中的细观参数取值讨论[J]. 工程地质学报, 30(5): 1669-1677. doi: 10. 13544/j.cnki.jeg.2022-0274.
    引用本文: 关岩鹏, 梁涛, 刘晓红, 等. 2022. 掘削卵砾石地层颗粒离散元模拟中的细观参数取值讨论[J]. 工程地质学报, 30(5): 1669-1677. doi: 10. 13544/j.cnki.jeg.2022-0274.
    Guan Yanpeng, Liang Tao, Liu Xiaohong, et al. 2022. Discussions on value of meso parameters in particle flow simulation of excavated gravel stratum[J]. Journal of Engineering Geology, 30(5): 1669-1677. doi: 10.13544/j.cnki.jeg.2022-0274.
    Citation: Guan Yanpeng, Liang Tao, Liu Xiaohong, et al. 2022. Discussions on value of meso parameters in particle flow simulation of excavated gravel stratum[J]. Journal of Engineering Geology, 30(5): 1669-1677. doi: 10.13544/j.cnki.jeg.2022-0274.

    掘削卵砾石地层颗粒离散元模拟中的细观参数取值讨论

    DISCUSSIONS ON VALUE OF MESO PARAMETERS IN PARTICLE FLOW SIMULATION OF EXCAVATED GRAVEL STRATUM

    • 摘要: 卵砾石地层被掘削时,其主要破坏模式并非一般的宏观整体剪切破坏,而是刀具切入卵砾石间的缝隙,将卵砾石颗粒剥离出原始地层,该过程较为契合颗粒离散元的物理力学假设。为确定掘削工况下的颗粒材料最优细观参数,对不同的颗粒接触法向刚度、接触刚度比、粒间摩擦系数、颗粒形状、颗粒尺寸等的颗粒材料开展了截割三维仿真试验,并分析研究了不同细观参数对掘削效果的影响。计算结果显示:颗粒接触法向刚度、接触刚度比的多种细观参数组合可以对应同一个宏观弹性模量值,接触刚度比大的细观参数组合的抗掘削能力更大。颗粒形状、粒间摩擦系数的多种细观参数组合可以对应同一个内摩擦角值,形状复杂的颗粒材料具有更大的抗掘削能力。在宏观参数相同的情况下,平均粒径更大的颗粒材料抗掘削能力更大。因此,利用颗粒离散元模拟掘削卵砾石地层问题时,除需保证虚拟颗粒材料的宏观整体剪切破坏响应与真实材料基本一致外,还需根据材料的抗掘削能力进一步标定细观参数,以获得更贴近实际情况的模拟效果。文章提出的方法可以为其他颗粒离散元掘削工况数值模拟中的参数标定提供参照依据。

       

      Abstract: When the gravel layer is excavated,the main failure mode is not the general macro overall shear failure. Instead,it is a process that a cutting tool cuts into the gap between pebbles and gravels to peel the pebbles and gravels out of the original stratum. This process is more in line with the physical and mechanical hypothesis of particle discrete element. In order to determine the optimal meso parameters of granular materials under excavation conditions,the three-dimensional cutting simulation is carried out for granular materials with different combination of meso parameters. The parameters include particle contact normal stiffness,contact stiffness ratio,inter particle friction coefficient,particle shape,and particle size. The effects of different meso parameters on excavation are analyzed and studied. The calculation results show that a variety of combinations of meso parameters,such as the normal stiffness of particle contact and the contact stiffness ratio can correspond to the same macro elastic modulus value. The combination of meso parameters with large contact stiffness ratio has greater capability for resisting excavation. The combination of multiple meso parameters of particle shape and inter particle friction coefficient can correspond to the same internal friction angle value. The particle material with complex shape has greater capability for resisting digging. Under the same macro parameters,the larger the average particle size,the greater the resisting digging capability. Therefore,when using the particle discrete element to simulate the excavation of gravel stratum,it is also necessary to further calibrate the meso parameters according to the excavation resistance ability of the material and to obtain a simulation effect closer to the actual situation in addition to ensuring that the macroscopic overall shear failure response of the virtual particle material is basically consistent with the real material. The method proposed in this paper can provide a reference for the parameter calibration of other particle discrete element numerical simulation of excavation conditions.

       

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