A Laboratory Study on the Influence of Anisotropy on the Soil Behavior

Abstract

Anisotropy refers to any directional-dependence on material property. In recent years, the anisotropy of intermediate-strain behavior and shear strength, small-strain stiffness anisotropy has attracted attention. The main aim of this paper is to clarify the influence of inherent anisotropy on the compressibility characteristics and shear strength behavior of fine-grained soils. A special manufactured device has been made in order to prepare and collect the samples in different directions. Then, a series of conventional tests have been carried out on the soil samples consists of unconfined compressive and Oedometer tests. Low plasticity clay has been used with three liquidity indices (0.22, 0.32, and 0.44) in order to achieve the goal of the study. The results have showed that the anisotropy had an impact on the undrained shear strength of cohesive soil and the soil strength can be considered as strength anisotropy. The higher anisotropy angle causes the more reduction in the shear strength. The settlement is affected by anisotropy, increasing of the anisotropy leads to the increase of the settlement, the compression and the swelling indices. The coefficient of consolidation in the vertical direction is lower than the coefficient in inclined direction and the ratio of (ch/cv) tends to increase with anisotropy angle the highest ratio is 1.4.