Soil arching effect is a common phenomenon within geogrid-reinforced and pile-supported (GRPS) embankments. It is in nature a three-dimensional (3-D) problem and a series of soil arching would form within the embankment fill. In this study, the group effect of soil arching is investigated using a 3-D finite element model. The numerical results show a good agreement with the measured data from a full scale experiment. By controlling the settlements of subsoil at different locations, the variations of soil arching are analyzed. It is found that the soil arching becomes more obvious when lowering the settlement of the underlying subsoil. But this settlement has little influence on the soil arching next to it. The heights of soil arching at the middle and shoulder regions of the embankment fill are close to each other and they reach a limit value when the subsoil settlement continues to increase.