Failure modes and inclined bearing capacity of a modified suction caisson in sand

Experiments and simulations are undertaken on the bearing behavior of a modified suction caisson (MSC) in sand under inclined load. Results show that the MSC movement modes include forward rotation, backward rotation, translations mainly along the horizontal and vertical directions. When the MSC rotates forward, the earth pressure generated by the upper soil in front of the MSC plays an important part of the capacity. The lower passive earth pressure is crucial when the backward rotation occurs. When the MSC mainly moves horizontally, the soil in front of the MSC is entirely aroused. For the MSC mainly translates vertically, the passive suction is an important part of the bearing capacity. Moreover, the earth pressure induced by the soil in front of the external structure cannot be ignored when the MSC rotates forward and moves horizontally. In addition, the inclined loading rate shows a significant impact on the inclined bearing behavior. In the case of rotation occurring, both the earth pressure and passive suction display positive correlations with the loading rate. As loading rate increases, the increment of passive suction for forward rotation is greater than that for backward rotation, while the increment of earth pressure is greater for backward rotation.