Degradation Characteristics of Saturated Marine Silty Sand Under Longterm Cyclic Loading

Abstract:

In order to study the long term cyclic degradation characteristics of saturated marine silty sand,a series of monotonic and cyclic undrained triaxial tests were conducted on isotropically and anisotropically consolidated natural undisturbed saturated silty sand with the shear wave measured by bender element system during cyclic loading.The influences of consolidation mode,cyclic stress ratio and cyclic number on the reduction of stiffness and strength of saturated sand were mainly analyzed.The experimental results show that under the same consolidated condition the undrained strength and stiffness of saturated sand markedly reduce with the increase of the cyclic stress ratio and the progressive number of cycles.On the other hand,anisotropic consolidation decelerates the degradation of stiffness under the same cyclic stress ratio.The dynamic deviatoric stress level is used to describe the reduction of stiffness and strength of saturated marine silty sand under cyclic loading.

Key words:anisotropic consolidation; stiffness; strength; cyclic degradation; dynamic deviatoric stress level