Anisotropy Studies on Cuboidal Shear Device

Anisotropy of clays was studied from cuboidal shear tests on two different clays that were artificially sedimented in a slurry consolidometer. These were supplemented by consolidation tests on specimens cut at different orientations. For one-dimensionally consolidated specimens, a significant increase was observed in the angle of internal friction when the specimens were loaded horizontally. For isotropically consolidated specimens, the angle of internal friction was about the same for vertical and horizontal loading. From the limited data available, it appears that the difference increases with the inherent anisotropy of the clay fabric. It was also found that when the one-dimensionally consolidated clay specimen is loaded horizontally, the rotation of principal stresses takes place. This results in the development of very high pore pressures at failure. The substantial increase in the angle of internal friction and the development of very high pore pressures at failure for horizontal loading of one-dimensionally consolidated clays are very important considerations in the geotechnical problems in which the soil is loaded horizontally.