In this paper, soil-water coupling analyses with finite element method are conducted to investigate the long-term displacements of two-pile foundation installed in saturated cohesive soils under different loading condition. As constitutive model for clayey soil, elasto-plastic bounding surface model is considered, which is a sophisticated elasto-plastic model for normally and over consolidated soils. The influence of loading intensity and consolidation process are considered carefully. The analyses showed that the elasto-plastic bounding surface model may provide a realistic stress distribution within the soil mass around the piles. Also as conclusion of a series of analyses, the followings are clarified; 1) the long-term behavior of two-pile group system; 2) the mechanism of how the space between piles affects the long-term displacements.