Anisotropy of Normally Consolidated San Francisco Bay Mud
Consolidated-undrained tests were performed on intact specimens of San Francisco Bay mud to study the anisotropic behavior of a normally consolidated clay. Large cylindrical block samples were obtained from an excavation in reclaimed tidelands south of the San Francisco International Airport. Evidence of soil fabric and its relation to the stratigraphy of the area were studied in preparation for the investigation of anisotropy. Cubical specimens were trimmed from the block samples and tested in triaxial compression with vertical and horizontal material axes. Consolidation characteristics, as well as stress-strain, pore pressure, and strength relations, were obtained along with lateral strains in two perpendicular directions. The experimental results were carefully evaluated and showed that the clay behaved as an orthotropic material, but for practical purposes could be characterized as being cross-anisotropic. The cross-anisotropic, elastic parameters were determined and related to the initial inclinations of the effective stress paths for vertical and horizontal specimens.