In recent years, it has become necessary to construct port structures at the outer sea of greater depth. A new type caisson having inclined walls is suitable for such a site condition. No method is, however, available to estimate the filling sand pressure acting on a inclined wall. Furthermore, the calculation method for the filling pressure is not well-established when the distance between walls is small.
　For these reasons, a series of large scale model test with FEM analysis was carried out to clarify the influence of inclination of the wall and distance of the walls. The major findings of this study are as follows: the filling pressure decreases with increasing inclination of the wall and with decreasing distance of the walls, and the posibility to evaluate the filling pressure by FEM was confirmed.