Analysis of sliding mechanism of soil material based on non-coaxial finite deformation theory

为了模拟局部剪切带的形成，这是常见的在大变形的土壤，我们首先提出了一个系统的扩展著名的剑桥模型开发的小应变模型有限应变/变形，然后纳入非共轴term的模型。最后，将变形限制在不排水平面应变条件下，我们研究了非共轴项对剪切带形成的影响。结果是：1）非共轴项的引入对法向应力差下的瞬时剪切模量没有影响，而使剪应力下的瞬时剪切模量变小。2)非共轴项使椭圆/双曲边界的处理变得容易。3)简单剪切模量的行为，这是这里提出的一个新的措施，看到的可达性剪切带的形成，表明，在临界状态附近，非共轴模型。独立 ...更多信息 本文还采用非共轴剑桥模型对剪切带的形成进行了有限元分析。基于更新的拉格朗日格式，将有限应变有限元法表述为土/水耦合形式。在不引入任何初始缺陷的情况下，给出了一个经典的刚性冲压问题中剪切带形成的演示。1）假定孔隙流体为达西定律，基于有限应变理论，总结了耦合问题的控制方程。2）基于更新的拉格朗日格式，对控制方程进行离散，导出了有限元格式。这里创建的程序被称为SHEBLA。3)而不会在材料元件中引入任何缺陷。我们证明了剪切带的形成在地面上的冲压问题作为变形的有限元网格，也作为局部应变分布。4)观察剪切带的形成过程，发现剪切带第一次出现在加载板边缘附近，并向对称轴方向延伸。形成剪切带的单元的应力状态先达到双曲线区，最后达到抛物线区。然而，剪切带首先出现的单元不一定首先通过E/H边界。5)观察有效应力路径，我们发现在剪切带延伸过程中，被剪切带包围的楔形体中的单元和加载板正下方的单元都经历了一次卸载。6)最后我们发现，在巴赫步骤的基础应力分布是相似的经验结果粘性土。少

In order to simulate the formation of localized shear bands, which is commonly observed during large deformation of soils, we first presented a systematic extension of the well known Cam-clay model developed for small strains to the model for finite strain/deformations and then incorporated a non-coaxial tern in the model. Finally, confining the deformation to undrained plane strain conditions, we examined the effects of the non-coaxial term on the shear bands formation. As a result: 1)The incorporation of the non-coaxial term has no effect on the instantaneous shear modulus for the normal stress difference and it makes the instantaneous shear modulus for the shear stress smaller. 2)The non-coaxial term makes easy of access to the elliptic/hyperbolic boundary. 3)The behavior of the simple shearing modulus, which is proposed here as a new measure to see the accessibility to shear bands formation, shows that, in the neighborhood of critical state, the non-coaxial models are. independentl … More y of the kinematic constraint, more inclined to instability by localization of deformation than the coaxial model.Furthermore we investigated the formation of the shear bands by employing the finite element method with a non-coaxial Cam-clay model. This finite element method for finite strains is formulated as a soil/water coupling form based on the updated Lagrangean scheme. A demonstration of shear bands formation is given in a classical rigid punch problem without introducing any initial imperfections into the material elements. We can offer the following remarks as conclusions: 1)Assuming Darcy's law for the notion of pore fluid, we summarized the governing equations for the coupling problem based on the finite strain theory. 2)We derived the finite element formation by discretizing the governing equations based on the updated Lagrangean scheme. The program created here is called SHEBLA. 3)Without introducing any imperfections into the material elements. we demonstrated the formation of shear bands in the ground for the punch problem as the deformation of finite element meshes and also as the localized strain distribution. 4)Observing the process for the formation of shear bands, we found that the shear bands occur for the first time just arround the edge of the loading plate and extend towards the symmetric axis. The stress state of the elements which form the shear bands reaches the hyperbolic region and then finally the parabolic region. The element in which a shear band occurs first, however, does not necessarily pass the E/H boundary first. 5)Observing the effective stress path, we discovered that both the element in the wedge surrounded by the shear bands and the element just beneath the loading plate experience unloading once during the extension of the shear bands. 6)And finally. we found that the distribution of footing stress at bach step is similar to the empirical results for cohesive soils. Less