为全面、深入地揭示脆性岩石的变形和屈服特性,以锦屏T26y和T2b脆性大理岩峰前和峰后循环加卸载试验为基础,分析岩石的弹塑性耦合性质、应变硬化软化性质和关联与非关联流动法则,定义考虑围压影响的塑性内变量以考虑应力历史对屈服过程的影响,进而建立脆性大理岩的弹塑性耦合力学模型,该模型能全面地反映脆性大理岩的弹塑性耦合、应变硬化软化和剪胀特性。针对所提出的弹塑性耦合模型,提出相应的数值迭代计算方法,并在有限差分软件FLAC3D进行实现。通过模拟脆性岩石的室内常规三轴压缩试验表明,所提出的力学模型可以较好地反映脆性岩石的主要力学特性。研究成果为更好地理解和分析脆性岩石的屈服破坏过程提供重要的参考。
Based on the results of cyclicloading tests of two kinds of marbles T26 y and T2b from Jinping II hydropower station,the elastoplastic coupling,strain-hardening and softening,shear dilatancy characteristics of rock are studied.Then,an elastoplastic coupling mechanical model is proposed with taking the following aspects into consideration:(1) A plastic internal variable which takes the influence of confining pressure into consideration is defined.(2) The variation of elastic parameters with plastic strain is concerned.(3) Based on the Mohr-Coulomb yield criterion,the evolution law of strength parameters during the plastic deformation is put forward.(4) The applicability of the generalized normality rule is validated and the method to handle shear dilatancy is proposed.The elatoplastic coupling model is embedded through the fast Lagrangian analysis of continua in three-dimension(FLAC3D) and is simulated by the triaxial compression test.The results show that the constitutive model can reflect properly the main mechanical characteristics of rock.Then,the unloading confining pressure tests are also simulated and the deformation and strength characteristics of marble are well obtained.The research results provide important reference to the understanding and analysis of yield process of brittle rock.