VARIATION OF FABRIC ANISOTROPY OF KAOLINITE IN TRIAXIAL LOADING

By measuring electrical conductivity in two perpendicular directions, the variation of fabric anisotropy of kaolinite is determined during o ne-dimensional (K-o), anisotropic (sigma(1)/sigma(3) = constant), and isotropic (sigma(1)/sigma(3) = 1) consolidation tests. To verify the v alidity of test results, the fabric anisotropy is determined at select ed stages of loading by analyzing electron micrograph images of vertic al and horizontal sections of parent specimens. The results from the t wo independent techniques are in agreement with each other. The result s reveal aspects that can aid in the process of constitutive modeling of clays. In general, it is found that an isotropic consolidation load ing or an anisotropic consolidation loading in extension, which causes rotation of principal strain directions, decreases the fabric anisotr opy developed during prior K-o consolidation. The initial fabric aniso tropy, however, cannot easily be erased or reversed by such a loading.