Abstract:
In order to predict ground behavior subjected to cyclic loading such as that induced by earthquake, it is necessary to accurately evaluate the deformation characteristics of soils subjected to cyclic loading and develop a model which expresses these deformation characteristics appropriately. This paper provides a simple three-dimensional elasto-plastic model for sand subjected to large cyclic loading. It is an extension of the work on one-dimensional modeling of the cyclic loading stress-strain relationships of sand (De
Silva 2008), in which a series of large amplitude cyclic torsional shear tests were implemented on specimens of sand. The concept of the model with infinite number of nesting surfaces (INS model) (Mrozet al. 1978) was employed to introduce the Masing's rule, which has been often used in the onedimensional modeling of the cyclic stress-strain relationships, into the three-dimensional modeling. In thezconcept of the INS model, the active loading and stress reversal surfaces are defined to express the cyclic
deformation behavior. In the proposed model, the effects of cyclic hardening behavior which were observed in the torsional shear test results were taken into account by using the relationship between the accumulated deviator plastic strain. Moreover, the stress-dilatation relationship was defined by the relationship between the ratio of the plastic volumetric strain to the plastic deviator strain and the size of the active loading surface. The proposed model was applied to simulate stress-strain relationships of dense sand subjected to drained large cyclic loading.
