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目的:建立三轴压缩作用下考虑受损基元承载影响的岩石材料损伤本构关系,并将其应用于工程实际。创新点:1.进行岩石损伤机理分析,探讨损伤阈值存在的原因,提出损伤修正系数,确定受损基元与无损基元的应力分配关系;2.建立能够反映岩石破裂全过程的损伤本构模型,验证模型的合理性并实现其程序化。方法:1.通过数值计算探讨岩石在初始缺陷下的损伤劣化机理,将不同初始状态的岩石定义为不同岩性的无损材料,建立合理的损伤模型;2.基于Mohr-Coulomb准则,结合连续损伤和统计理论,推导基于受损基元承载影响的岩石材料本构方程;3.与前人试验数据及理论成果进行对比,验证本构模型的合理性,最后利用C++语言编译的动态链接库(DLL)实现有限差分软件FLAC3D的二次开发,实现模型的工程应用。结论:1.岩体损伤劣化是无损基元发生物理性状改变导致材料刚度变小的结果,受损基元与无损基元的应力分配关系与岩体的瞬时损伤状态和应力状态有关;2.建立的岩石损伤本构模型与试验数据的拟合精度较高,能够准确地描述岩石的应力-应变关系;3.数值模拟结果与现场监测数据的吻合程度较高,表明该模型能够合理反映软弱岩体的损伤劣化效应。
OBJECTIVE: To establish the damage constitutive relation of rock material under triaxial compression considering the bearing of damaged element, and to apply it to engineering practice. Innovative points: 1. To analyze the mechanism of rock damage, to explore the reasons for the existence of damage threshold, to propose the damage correction factor, to determine the damaged element and non-destructive element stress distribution relationship; 2. To establish the entire process of rock failure to reflect the damage constitutive Model, verify the rationality of the model and achieve its programming. Methods: 1. Through the numerical calculation, the damage mechanism of rock under initial flaw was discussed. Rocks with different initial states were defined as non-destructive material with different lithologies, and a reasonable damage model was established. 2. Based on Mohr-Coulomb criterion, combined with continuous damage And the statistical theory, the constitutive equations of rock material based on the bearing of damaged elements are deduced.3. Compared with the previous experimental data and theoretical results, the rationality of the constitutive model is verified. Finally, the dynamic link library compiled by C ++ DLL) to realize the secondary development of finite difference software FLAC3D and realize the engineering application of the model. The conclusion is as follows: 1. The damage of rock mass is the result of the change of physical properties of non-destructive cells resulting in the decrease of material stiffness. The stress distribution relationship between damaged cells and non-destructive elements is related to the instantaneous damage state and stress state of rock mass.2. The established rock damage constitutive model and experimental data have higher fitting accuracy and can accurately describe the stress-strain relationship of rock.3. The numerical simulation results are in good agreement with the on-site monitoring data, indicating that the model can reasonably reflect the weakness Degradation effect of rock mass.