平行黏结模型中细观参数对宏观特性影响研究

STUDY OF EFFECTS OF MICROPARAMETERS ON MACROPROPERTIES FOR PARALLEL BONDED MODEL

采用理论分析与数值模拟相结合的方法,对平行黏结模型中细观参数对宏观特性的影响进行系统研究。首先通过理论研究,定性提出细观参数与宏观特性的理论公式,然后运用PFC2D数值模拟,定量地给出两者之间的关系式。研究表明:(1)计算模型宏观弹性模量主要由颗粒接触杨氏模量和颗粒黏结杨氏模量决定,且与二者均呈线性关系,同时受颗粒接触法向刚度与切向刚度之比、颗粒黏结法向刚度与切向刚度之比及颗粒尺寸的影响,且均呈对数关系;(2)泊松比主要由颗粒刚度决定,且呈对数关系,受颗粒尺寸的影响较小;(3)抗压强度由颗粒黏结应力比τb,m/σb,m决定,受颗粒摩擦因数的影响轻微,当0<τb,m/σb,m<2时,抗压强度主要受τb,m的影响,当τb,m/σb,m≥2时,抗压强度主要受σb,m的影响。并给出具有一定参考意义的相关关系式,结合实例进一步对相关分析式的可靠性进行论证。研究成果对快速、合理确定PFC模型细观参数具有指导意义。

According to the theoretical analysis combining with the numerical simulation method, the effect of microparameters on macroproperties of parallel bonded model is investigated systematically. Firstly, the theoretical formulas between microparameters and macroproperties are proposed qualitatively; then, the quantitative relationships are put forward by PFC20 software. The research result shows that： （1） The Young＇s modulus of the calculation model is mainly determined by the contact Young＇s modulus of particles and bonded Young＇s modulus of particles; and they are in a linear relationship with the Young＇s modulus all. What＇s more, The Young＇s modulus is affected by contact stiffness ratio of particles, bound stiffness ratio of particles and particle size; and the three ones are logarithmic relationship with the Young＇s modulus all. （2） The Poisson＇s ratio is mainly determined by stiffness ratio of particles and they are in a linear relationship. Simultaneously, it is slightly affected by particle size. （3） The compressive strength is mainly determined by bound stress ratio of particles τb, m/σb, m; and it is slightly affected by friction factor/z When 0〈τb, m/σb, m〈2, the compressive strength is mainly influenced by bound tangent stress τb, m; when τb, m/σb, m ≥2, it is mainly influenced by bound normal stress σb, m. Then the correlative relations with certain referential significance are given; and the reliability of correlative relations is proved by case study. The study has directive meaning to quickly and reasonably determine the microparameters of PFC model.