To truly describe the reaction of saturated sands under cyclic loading

a parameter considering macroscopically dilatancy stage on fabric changes is necessary. Based on the existing constitutive model dependent on a state parameter

a fabric-dilatancy internal variable z considering the influence of the fabric change is introduced. It is still based on phase transformation state. With state parameter the deformation tendency of sand at any time or any conditions can be judged. Through the z effected on the dilatancy

plastic deformation accumulation is considered when load increment reversals. In this paper

an elastoplastic constitutive model of saturated dense sand under cyclic loading is established. According to experimental phenomenon analysis

plastic modulus in the existing model is modified

it can simulate well expansion shrinkage change process of sands under drained cyclic loading. Finally

in view of the dense sands during triaxial drained cyclic loading

a comparison between model simulations and a sequence of experimental results shows that the model can generally reflect the deformation behavior of being given sand.