Initial and Evolving Stress-Strain Anisotropy of Sedimented Clay

粘性土壤上的结构设计需要定量了解各向异性应力应变条件下的粘土-结构相互作用。 这项研究开发了确定粘土各向异性影响的实验方法。 如果没有关于粘土沉积物不排水和排水响应的足够数据，对复杂粘土-结构相互作用问题（垫式基础、支撑开挖、隧道等）的合理分析是不可行的。 这项研究开发了一种包含应力应变各向异性的“广义”本构关系。 本研究使用独特的定向单元 (DSC) 装置，通过改变法向应力和剪应力并作用于立方体土壤样本的四个面，完全控制主应力方向。 该研究采用了不同超固结比下的不排水和排水测试，并确定了固结粘土的“初始”各向异性如何因随后导致塑性变形的应变而变化。

The design of structures on cohesive soils requires a quantitative understanding of the clay-structure interactions under anisotropic stress-strain conditions. This research develops experimental methods to determine the effects of anisotropy in clays. Rational analyses of complex clay-structure interaction problems (mat foundations, braced excavations, tunnels, etc.) are not feasible without adequate data on undrained and drained response of clay deposits. This study develops a "generalized" constitutive relationship incorporating the stress-strain anisotropy. This research uses a unique Directional Cell (DSC) device to fully control the major principal stress direction by varying the normal and shear stresses and acting on four faces of a cubical soil sample. The study employs both undrained and drained testing at varying overconsolidaiton ratios and determines how "initial" anisotropy of consolidated clays change due to subsequent straining that causes plastic deformations.