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谭鑫, 胡跃刚, 尹心, 曹文贵. 颗粒离散元岩石模型的宏细观抗拉强度关联[J]. 力学学报.
引用本文: 谭鑫, 胡跃刚, 尹心, 曹文贵. 颗粒离散元岩石模型的宏细观抗拉强度关联[J]. 力学学报.
MACRO-MICRO SCALE TENSILE STRENGTH CORRELATIONS FOR PARTICLE-DEM BASED ROCK MODELS[J]. Chinese Journal of Theoretical and Applied Mechanics.
Citation: MACRO-MICRO SCALE TENSILE STRENGTH CORRELATIONS FOR PARTICLE-DEM BASED ROCK MODELS[J]. Chinese Journal of Theoretical and Applied Mechanics.

颗粒离散元岩石模型的宏细观抗拉强度关联

MACRO-MICRO SCALE TENSILE STRENGTH CORRELATIONS FOR PARTICLE-DEM BASED ROCK MODELS

  • 摘要: 颗粒离散元数值模型由于具有反映材料宏细观力学特征的天然优势,而被大量学者采用开展岩石力学课题相关研究,但DEM数值模型涉及的跨尺度关联和参数标定问题给研究者带了挑战,且尚未形成获得统一认可的定量分析方法。本文基于规则排列的圆形颗粒DEM岩石试件拉伸模型,开展了细观接触破裂模式与宏观拉伸破坏强度相关性的力学分析,指出岩石试样宏观抗拉强度取决于内部细观接触破裂模式,而细观破裂模式则受到接触抗拉强度、接触抗剪强度、接触法向刚度、接触切向刚度、甚至颗粒大小及排列方式的共同影响。根据理论分析及数值模拟结果提出了4种细观破裂模式及相应宏观抗拉强度理论计算公式,并将公式修正应用于随机颗粒排列的类岩石材料DEM模型,从细观角度揭示了宏观DEM岩石材料拉伸破坏机理,构建了宏细观抗拉强度参数关联。所建立关联公式的合理性得到了大量随机数值模拟结果的有效验证,可为研究者利用颗粒DEM数值模型进行岩石、混凝土等类脆性材料模拟的参数选取及标定工作提供重要的参考依据。

     

    Abstract: The Discrete Element Method (DEM) numerical model, due to its inherent capability to reflect both macroscopic and microscopic mechanical characteristics of materials, has been widely adopted by many scholars in the field of rock mechanics research. However, the challenges of scale bridging and parameter calibration associated with DEM numerical simulations have posed significant challenges to researchers. Moreover, a unified and widely accepted quantitative analysis method has yet to be established. In this study, based on a DEM model of circular particles arranged in a regular pattern, we conducted a mechanical analysis of the correlation between microscopic contact failure modes and macroscopic tensile strength. Our findings indicate that the macroscopic tensile strength of rock specimens depends on the internal microscopic contact failure modes. These microscopic failure modes are influenced by several factors, including contact tensile strength, contact shear strength, contact normal stiffness, contact tangential stiffness, particle size, and arrangement. Through theoretical analysis and numerical simulation results, we proposed four microscopic failure modes and corresponding theoretical formulas for calculating macroscopic tensile strength. These formulas were then applied to DEM models of randomly arranged particles. From a microscopic perspective, we revealed the mechanisms of macroscopic tensile failure in DEM rock-like materials and established a correlation for macroscopic tensile strength parameters. The validity of the established correlation formulas was effectively verified by a large number of random numerical simulation results. This work provides an important reference for researchers in selecting and calibrating parameters for simulating brittle materials such as rocks and concrete using particle-based DEM numerical models.

     

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