The development of geotechnical plasticity is reviewed and some problems of applying the classical plastic mechanics (CPM) to geomaterials are analyzed, and then CPM’s three hypotheses not fitted the deformation mech...The development of geotechnical plasticity is reviewed and some problems of applying the classical plastic mechanics (CPM) to geomaterials are analyzed, and then CPM’s three hypotheses not fitted the deformation mechanism of geomaterials are pointed out. By giving up the three hypotheses, a generalized plastic potential theory can be obtained from solid mechanics directly, and then the traditional plastic mechanics can be changed to a more generalized plastic mechanics, namely generalized plastic mechanics (GPM). The GPM adopts the component theory as theoretical base, so it can reflect the influence of transition of stress path. The unreasonable phenomena such as excessive dilatancy caused by adopting the normality-flow law can be avoided, and the error caused by the arbitrary assumption of plastic potential surfaces cannot be produced. The yield surface theory, hardening laws and stress-strain relations of GPM are given, and a GPM including the rotation of principal stress axes is also established. It is pointed out that the yield condition is a state parameter as well as a test parameter, and it can only be given by test. After the practical application, it is shown that the GPM cannot only be applied to the modeling theory of geomaterials but also to other fields of geomechanics such as limit analysis.展开更多
The traditional unified viscoplasticity constitutive model can be only applied to metal materials.The study of the unified constitutive theory for metal materials has discovered the correlation between the classical p...The traditional unified viscoplasticity constitutive model can be only applied to metal materials.The study of the unified constitutive theory for metal materials has discovered the correlation between the classical plasticity theory and the unified viscoplasticity constitutive model,thus leading to the con-cepts of the classic plastic potential and yield surface in the unified constitutive model.Moreover,this research has given the continuous expression of the classical plastic multiplier and presented the corresponding constructive method,which extends its physical significance and lays down a good foundation for the application of the unified constitutive theory to the material analysis in more fields.This paper also introduces the unified constitutive model for metal materials and geo-materials.The numerical simulation indicates that the construction should be both reasonable and practical.展开更多
文摘The development of geotechnical plasticity is reviewed and some problems of applying the classical plastic mechanics (CPM) to geomaterials are analyzed, and then CPM’s three hypotheses not fitted the deformation mechanism of geomaterials are pointed out. By giving up the three hypotheses, a generalized plastic potential theory can be obtained from solid mechanics directly, and then the traditional plastic mechanics can be changed to a more generalized plastic mechanics, namely generalized plastic mechanics (GPM). The GPM adopts the component theory as theoretical base, so it can reflect the influence of transition of stress path. The unreasonable phenomena such as excessive dilatancy caused by adopting the normality-flow law can be avoided, and the error caused by the arbitrary assumption of plastic potential surfaces cannot be produced. The yield surface theory, hardening laws and stress-strain relations of GPM are given, and a GPM including the rotation of principal stress axes is also established. It is pointed out that the yield condition is a state parameter as well as a test parameter, and it can only be given by test. After the practical application, it is shown that the GPM cannot only be applied to the modeling theory of geomaterials but also to other fields of geomechanics such as limit analysis.
基金Supported by the National Natural Science Foundation of China (Grant No. 90410012)
文摘The traditional unified viscoplasticity constitutive model can be only applied to metal materials.The study of the unified constitutive theory for metal materials has discovered the correlation between the classical plasticity theory and the unified viscoplasticity constitutive model,thus leading to the con-cepts of the classic plastic potential and yield surface in the unified constitutive model.Moreover,this research has given the continuous expression of the classical plastic multiplier and presented the corresponding constructive method,which extends its physical significance and lays down a good foundation for the application of the unified constitutive theory to the material analysis in more fields.This paper also introduces the unified constitutive model for metal materials and geo-materials.The numerical simulation indicates that the construction should be both reasonable and practical.
