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建立能够体现岩石的初始损伤以及损伤部分仍能承受一定应力的新型岩石损伤模型.基于损伤演变过程提出新的损伤定义,将损伤部分分为损伤材料和因材料损伤而变化的微缺陷,提出损伤材料与因材料损伤而变化的微缺陷之间的影响因子γ,给出其确定方法,并研究其基本性质;通过岩石微观受力分析,建立岩石损伤模型;深入探讨岩石有效应力与名义应力的关系,引进岩石微元强度,服从对数正态分布,建立考虑损伤阈值影响的岩石损伤统计本构模型,并提出确定分布参数的方法.结果表明:该模型能够充分反映岩石损伤阈值的影响及应变软化特性,且参数物理意义明确,应用较为方便;与试验结果比较,本文模型理论曲线与试验曲线匹配度达87.2%,高于前人模型曲线的81.3%,说明该模型更为合理、可行.根据本文理论得出的损伤演化曲线符合S型曲线规律,能够很好地反映岩石压缩过程中的变形阶段划分.
Establish a new rock damage model that can reflect the initial damage of the rock and the damage part can still withstand a certain stress. Based on the damage evolution process, a new damage definition is proposed. The damage part is divided into damage material and micro defects due to material damage, and the damage is proposed. The influence factor γ between the material and the microdefects that change due to the damage of the material is given as the determination method, and its basic properties are studied; through rock microscopic force analysis, the rock damage model is established; the effective stress and nominal stress of the rock are deeply discussed. Relationships, the introduction of the strength of rock microelements, obey the lognormal distribution, establish a statistical damage constitutive model of rock considering the effect of damage threshold, and propose a method to determine the distribution parameters. The results show that the model can fully reflect the impact of rock damage threshold and The strain softening characteristics and the physical meaning of the parameters are clear and the application is more convenient. Compared with the experimental results, the matching degree between the model theoretical curve and the experimental curve is 87.2%, which is higher than 81.3% of the previous model curve, which shows that the model is more reasonable and feasible. According to the theory of this paper, the damage evolution curve conforms to the S-curve rule and can reflect the rock well. Stage compression deformation process of division.