摘要
分析了经典塑性力学用于岩土类材料的问题,它采用了3个不符合岩土材料变形机制的假设。从固体力学原理直接导出广义塑性位势理论,将经典塑性力学改造为更一般的塑性力学———广义塑性力学。广义塑性力学采用了塑性力学中的分量理论,能反映应力路径转折的影响,并避免了采用正交流动法则所引起的过大剪胀等不合理现象,也不会产生当前非关联流动法则中任意假定塑性势面引起的误差。给出了广义塑性力学的屈服面理论、硬化定律和应力-应变关系,并建立了考虑应力主轴旋转的广义塑性位势理论。屈服条件是状态参数,也是试验参数,只能由试验给出。应用表明,广义塑性力学可作为岩土材料的建模理论,还可应用于诸如极限分析等土力学的诸多领域,具有广阔的应用前景。
The development of geotechnical plasticity is reviewed and some problems of applying the classic plastic mechanics to geomaterials are analyzed, and then its three hypotheses not fit for 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 can not only be applied to the modeling theory of geomaterials but also to other fields of geomechanics, such as limit analysis.
出处
《中国工程科学》
2005年第11期21-36,共16页
Strategic Study of CAE
基金
国家自然科学基金资助项目(10402014)
关键词
岩土塑性力学
广义塑性力学
塑性势
屈服面
本构模型
geotechnical plastic mechanics
generalized plastic mechanics
plastic potential
yield surface
constitutive model
