簇平行黏结模型中微观参数对宏观参数影响的量纲研究

发布时间：2018-06-15 23:00

本文选题：岩石力学 + 颗粒流　；参考：《岩石力学与工程学报》2014年02期

【摘要】：首先分别采用传统加载程序和新加载程序,对利用簇平行黏结模型所建立的颗粒流试样的力学特性进行研究。同时采用新加载程序,分析加载速率和冻结期时步对颗粒流试样力学特性的影响。随后利用量纲分析法研究簇平行黏结模型中微观参数对宏观参数的影响,建立岩石材料宏观参数(弹性模量、泊松比、单轴抗压强度和单轴抗拉强度)与簇平行黏结模型中微观参数间的半定量关系。相关模拟结果表明:(1)利用传统加载程序计算得出的岩石应力应变曲线是不准确的,它高估了单轴抗压强度、单轴抗拉强度和弹性模量,且不能真实再现岩石峰后脆性特征;2种加载程序得出的岩石破坏形态差异很大。(2)结合新加载程序,簇平行黏结模型能得到合理的单轴抗压强度和单轴抗拉强度比值(UCS/TS)。在准静态范围内,加载速率与强度值没有相关性,这与试验结果吻合,加载速率对岩石应力应变曲线的影响主要在峰后阶段。(3)弹性模量主要与颗粒接触模量和颗粒接触刚度比相关,而泊松比主要与接触刚度比相关。为得到相同的泊松比值,簇平行黏结模型中的接触刚度比应大于平行黏结模型中的接触刚度比。单轴抗压强度和单轴抗拉强度主要受平行黏结强度比控制,另外单轴抗压强度受簇中颗粒数影响较大。
[Abstract]:Firstly, the mechanical properties of the granular flow specimens established by using the cluster parallel bonding model were studied by using the traditional loading program and the new loading program respectively. At the same time, the influence of loading rate and freezing time step on the mechanical properties of the granular flow specimen is analyzed by using the new loading program. Then the influence of micro parameters on macroscopic parameters in cluster parallel bonding model is studied by dimensional analysis method, and the macroscopic parameters (elastic modulus, Poisson's ratio) of rock materials are established. Semi-quantitative relationship between uniaxial compressive strength and uniaxial tensile strength and microscopic parameters in cluster parallel bonding model. The simulation results show that the stress-strain curves calculated by the traditional loading program are inaccurate, and the uniaxial compressive strength, uniaxial tensile strength and elastic modulus are overestimated. Moreover, the failure morphology of rock obtained from the two loading procedures can not be truly reproduced. (2) combined with the new loading program, the cluster parallel bonding model can obtain a reasonable uniaxial compressive strength and uniaxial tensile strength ratio (UCS / TSN). In the quasi-static range, there is no correlation between the loading rate and the strength value, which is consistent with the experimental results. The effect of loading rate on the stress-strain curve of rock is mainly related to the contact modulus of particles and the ratio of contact stiffness of particles, while Poisson's ratio is mainly related to the ratio of contact stiffness. In order to obtain the same Poisson ratio, the contact stiffness ratio in the cluster parallel bonding model should be greater than that in the parallel bonding model. The uniaxial compressive strength and uniaxial tensile strength are mainly controlled by the ratio of parallel bonding strength, and the uniaxial compressive strength is greatly affected by the number of particles in the cluster.
【作者单位】：中南大学计算地球科学研究中心;
【基金】：国家自然科学基金资助项目(11272359)
【分类号】：TU45

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