Abstract:

The cell of foundation soil is taken notable impact on dynamic deformation and dynamic strength behavior under rotation of principal stress axes by cyclic wave load. The apparatus for static and dynamic universal triaxial and torsional shear soil testing is employed to perform stress-controlled cyclic coupled vertical and torsional shear test by different cyclic stress paths. Through a series of tests on saturated clay, the dynamic deformation, stress-strain relationship and dynamic strength are systematically investigated under rotation of principal stress axes. It is found that stress-strain relation of shear stress and normal stress has obvious distinguishing between consolidated-undrained and unconsolidated-undrained coupling test by comparing the experiment data. Meanwhile, it is observed that stress-strain relationship curve gradually loosen and the secant modulus decayed as the cyclic number increased. Moreover, it is shown that the dynamic strength under major dynamic shear stress is less than the one under major normal stress by different elliptical stress paths. By conducting experiments on clay with changes in stress paths, the mechanical behavior can be investigated on which the establishment of proper constitutive model for soil is based.

Key words: saturated clay, cyclic stress path, coupling test of vertical and torsional dynamic test, dynamic strength, stress-strain relation