软土应力各向异性对基坑开挖变形影响的机理分析

摘要

Anisotropy has an important influence on soil's deformation character under complex stress state.The soil of unloading has its specific strength and deformation characteristics.An ideal elastoplastic model based on the modified Von Mise criterion is proposed and linked into ANSYS.Some excavations are simulated with this anisotropy constitutive model.The results show that the anisotropy has an important effect on the deformation of excavations.At the same time, the effect on the level deformation is different from the vertical deformation.It is relative to the width and depth of excavation.%软土条件下,应力各向异性对复杂状态下土体的变形规律有重要影响.卸载状态下的K0固结土体具有其特有的强度和变形特性.本文建立了一个简单、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模型,并将该本构模型耦合到ANSYS软件中,模拟分析了各向异性对基坑开挖变形的影响.结果表明:各向异性对土体的变形性状有重要影响,且对土体的水平变形和与竖向变形的影响程度与开挖宽度和开挖深度的比值有关.