Associate professor, Newark College of Engineering, Newark, N.J.
A method of preparing isotropic clay soil samples in the laboratory is given, where consolidation is accomplished under hydrostatic pressure. Direct shear tests were performed on specimens trimmed at different inclinations to the physical horizontal from the block samples prepared by this method. The ratio of undrained shear strengths in any direction to that in the vertical direction was found to be practically equal to one. Similar tests performed on specimens trimmed from samples of the same clay consolidated one-dimensionally showed this ratio to be maximum for horizontally trimmed specimens. Thus, for laboratory investigation, where isotropic test specimens are desired, soil samples should be consolidated hydrostatically and not one-dimensionally as the latter yields anisotropic samples.
Paper ID: JTE10054J