Post-cyclic strength behaviors of undisturbed soft soils with different degrees of reconsolidation

The soft soil after cyclic loading is often in an intermediate state between unconsolidated and fully reconsolidated after a period of time, which can be described by the concept of degree of reconsolidation. At present, there are few studies considering the effects of different degrees of reconsolidation on the post-cyclic strength behaviors of soils. Therefore, as eries of dynamic and static triaxial tests are carried out to study the post-cyclic strength behaviors of undisturbed soft soils at the Pearl River Estuary. The effects of the initial consolidated confining pressure, cyclic stress ratio and different degrees of reconsolidation on the post-cyclic strength behaviors of soils are analyzed. The test results show that the variation trends of stress-strain curves under different conditions are similar. The post-cyclic shear strength of soils increases with the increase of the initial confining pressure, cyclic stress ratio and degree of reconsolidation. When the confining pressure is 20 kPa and the degree of reconsolidation increases from 0 % to 100 %, the shear strength increases from 20.2 to 33.0 kPa. For the fully reconsolidated specimens after cyclic loading, when the confining pressure increases from 20 to 60 kPa, the corresponding shear strength increases from 33.0 to 39.5 kPa, respectively. On the other hand, there is a critical cyclic stress ratio, at which the post-cyclic shear strength basically equal to that of soils without cyclic loading under the same confining pressure.