Soft Soil Performances Under Combined Static and Cyclic Loading

Abstract

Mechanical properties of soft clays under combined static and cyclic stresses are experimental tested. The sensitivity of static stress and cyclic stress is examined in terms of the total and cyclic excess pore pressures and axial strains. Results show that total excess pore pressures and total axial strains generally depend on combined stress ratio. For a given combined stress ratio, the cyclic excess pore pressures and cyclic axial strains are largely determined by the cyclic stress ratio. A modified soil model is proposed to incorporate the effect of initial static shear stress together with the cyclic loading and is verified with the test data. Parametric analyses indicate that more severe degradation during cyclic loading can be expected even for a lower cyclic stress ratio given a higher combined stress ratio. For a fixed combined stress ratio, the total cyclic stress ratios and total axial strains are highly influenced by the cyclic degradation parameters.