平行黏结模型宏细观力学参数相关性研究

采用变量控制法较全面地分析了各细观参数与宏观参数的定量关系，表明：弹性模量E随颗粒模量Ec、黏结模量 、平行黏结半径乘子 呈线性增长，随颗粒刚度比kn /ks、黏结刚度比 呈对数减小；泊松比则主要受kn /ks和 的影响，两者之间呈对数关系；颗粒键的黏结强度决定了材料的强度，室内材料黏聚力c和抗拉强度 主要受法向平行黏结强度 、平行黏结强度比 的影响，随 线性增长，随 对数减小；摩擦角 主要受颗粒摩擦系数u影响，两者呈对数关系。分析裂隙扩展特征，表明材料法向黏结强度 和切向黏结强度 的相对大小决定裂纹分布规律，随 增大，岩样的拉破坏区域减少，而压剪破坏区域增加，破坏面由剪切破坏向共轭破坏发展；材料的强度离散性越小，岩样破坏趋于集中，破坏面明显，强度均值标准差比值 >3.5为宜； 增加，宏观破坏形式向共轭破坏发展。细观参数的选取除了匹配强度参数，同时还需要考虑破坏形式的一致，考虑多参数相互影响，建立了宏细观参数之间的经验公式，对细观参数进行优化选择，并做了实例验证。室内试验和数值模拟获得的峰值荷载、变形参数、剪切强度等数值接近，应力-应变演化规律相同，破坏形态一致，表明细观参数结果是可靠的。

Relationship between particle micro and macro mechanical parameters of parallel-bond model

Variable control method is used to comprehensively analyze the influence of all the microscopic parameters of parallel bond model on its macroscopic parameters, They are mainly manifested as: Parallel-bond modulus and particle contact modulus Ec are the main controlling factors of macro elastic modulus and there is a linear relationship between them. The Poisson's ratio is mainly affected by the particle stiffness ratio kn /ks and the parallel bond stiffness ratio and there is a logarithmic relationship between them. The bond strength of the particle bond determines the strength properties of the material. The cohesion c and tensile strength of interior materials are mainly influenced by the parallel-bond normal strength and the parallel-bond strength ratio ; they increase linearly with the parallel-bond normal strength and decrease logarithmically with the parallel-bond strength ratio 。 The friction angle is mainly affected by the friction coefficient u of the particles, and the two are in a logarithmic relationship. Analysis of fracture propagation characteristics shows that the relative sizes of the material's normal and tangential bond strengths determine the distribution of cracks. With the increase of parallel-bond strength ratio , the tensile failure area of the rock sample decreases, while the shear zone increases, and the failure surface breaks from the shear failure to conjugate damage. The smaller the dispersion of the strength of the material, the rock sample tends to focus on the destruction, the destruction of the surface is obvious, the ratio between the mean and the standard deviation of the parallel bond strengths more than 3.5 is appropriate; with the increase of parallel-bond stiffness ratio , the macroscopic damage develops to conjugate destruction. In addition to matching the strength parameters, the mesoscopic parameters need to consider the consistency of the failure modes. Considering the mutual influence of multiple parameters, the empirical formulas between the macro and meso parameters are established, the mesoscopic parameters are selected and optimized, and examples are verified. The values of peak loads, deformation parameters and shear strength obtained by indoor tests and numerical simulations are close to each other. The stress-strain evolution law is the same and the damage patterns are the same, indicating that the mesoscopic parameter results are reliable.