土体应力各向异性对深基坑开挖性状的影响

Anisotropic Behavior of Soft Clay and Its Effect on the Deformation of Deep Excavations

应力各向异性对复杂状态下土体的变形规律有重要影响。开挖状态下的K0固结土体具有其特有的变形和强度特性。本文提出了一个将各向异性强度准则等效到Von Mise强度准则的方法,建立了一个简单、便于工程使用且能够描述土体各向异性的理想弹塑性本构关系,并将该本构关系耦合到ANSYS软件中,模拟分析了深基坑开挖后的变形性状。并通过工程实例和经典的Drucker-Prager模型作了比较,分析结果表明各向异性对深基坑开挖变形的影响不容忽视。

Anisotropy has an important influence on soil＇s deformation character under complex stress state.The classical constitutive model of isotropy isn＇t suitable for the soil under the condition of consolidation state because it has a specific deformation and strength characteristics.An equivalent Von Mise criterion is proposed and it can reflect the anisotropic strength of soil.At the same time,an ideal elastoplastic model based on the modified Von Mise criterion is proposed and linked into ANSYS.A deep excavation is simulated with this anisotropy constitutive model and the Drucker-Prager model.The comparative results show that the anisotropy must be considered in the simulation of deep excavation.