基于残余强度变形阶段特征的岩石变形全过程统计损伤模拟方法

A statistical damage simulation method for rock full deformation process with consideration of the deformation characteristics of residual strength phase

岩石应变软化变形破坏全过程模拟是岩石力学研究的重要内容。首先在分析岩石应变软化变形全过程不同阶段变形特征基础上,针对现有岩石损伤模型难以反映岩石破坏后仍具残余强度特性的不足,假设受载岩石可抽象为损伤和未损伤两部分材料组成,其所受轴向荷载由这两部分共同承担,且损伤部分所受应力为残余强度,建立出可反映岩石破坏后仍具残余强度特征的新型损伤模型;其次,引进统计损伤理论,在探讨岩石微元强度合理度量方法的基础上,考虑岩石损伤阀值的影响,建立可反映岩石变形全过程特征的岩石统计损伤演化模型;然后,利用上述岩石损伤模型和损伤演化模型建立出可模拟岩石应变软化变形全过程的损伤统计本构模型,并建立其模型参数确定方法,该模型能较好地反映岩石峰后残余强度阶段变形特征;最后,通过实例分析与讨论,并与其他同类模型分析结果进行比较分析,表明本文模型与方法的合理性与优越性。

Simulation of the deformation process of strain softening rocks is an important issue in rock mechanics. Based on discussions of the deformation characteristics at different stages in the deformation process of strain softening rocks, a modified damage model reflecting the characteristics of residual strength after failure was established to deal with the inability of current rock damage models in reflecting the characteristics of residual strength after failure. In the proposed model, the rock is divided into two parts： damaged material and undamaged material, and the 10ad is supported by the two parts together, with the damaged material providing the support capability by residual strength. A new statistical damage evolvement model which can simulate the full deformation process of strain softening rocks is established by adopting statistical damage theory. Adopting the damage model and statistical damage evolvement model mentioned above, a statistical damage constitutive model which can simulate the full deformation process of strain softening rocks is developed, and a method for determining its parameters is proposed. The model can preferably describe the deformation characteristics of residual strength after failure. Finally, the analyses of example calculations indicate that the proposed constitutive model presented is reasonable and advantageous.