Associate professor of civil engineering, New Jersey Institute of Technology, Newark, N.J.
The cause and the nature of anisotropy in a cohesive soil was investigated by direct shear and triaxial compression tests. Samples formed under hydrostatic stress showed isotropic shear strength and pore pressure behavior as well as the lack of bias in soil fabric. When the samples from the same clay were molded under one-dimensional consolidation stress, the pore pressure was observed to be isotropic, but the effective stress shear strength was not. Also, these samples had oriented soil structure. The anisotropic strength resulted from the sample stress history and not from the stresses existing prior to shearing. The ratio between the pore pressure at failure and the mean consolidation pressure during remolding, as well as the inclination of the failure plane to the specimen axis, were observed to be essentially constant for all specimens.
Paper ID: JTE10513J