Initial and Evolving Stress-Strain Anisotropy of Sedimented Clay

粘性土结构的设计需要对各向异性应力-应变条件下粘土-结构相互作用的定量理解。本研究发展了测定粘土各向异性影响的实验方法。如果没有足够的粘土沉积物不排水和排水响应数据，对复杂的粘土-结构相互作用问题（垫基、支撑开挖、隧道等）进行合理分析是不可实现的。本研究建立了一个包含应力-应变各向异性的“广义”本构关系。本研究采用一种独特的定向单元（DSC）装置，通过改变正应力和剪应力并作用于立方体土样的四个面来完全控制主应力方向。该研究采用了不同过固结比下的不排水和排水试验，并确定了固结粘土的“初始”各向异性是如何因随后的应变而发生塑性变形的。

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.