The lateral deformation characteristic of coarse grained soil is an important basis for quantifying the settlement of port filling under different loads.Based on 12 sets of lateral confinement tests with different stress ratios,we obtain the changing trend of loading and unloading times and stress ratios on strain increment of coarse grained soil under lateral confinement condition,establish the calculation models of strain and plastic strain of coarse grained soil,and verify the rationality of the models in two-dimensional and three-dimensional space.The results show that there is a maximum depth of influence of surcharge stress in soil.When the stress ratio is the same,the strain increment and plastic strain increment under the lateral limit condition are independent of the incremental load value.The strain and plastic strain of coarse grained soil change exponentially with the increase of stress ratio,and the limit stress ratio is between 2.124 and 2.461.It is suggested that the upper part of the foundation should be strengthened by dynamic consolidation for many times during the construction and filling of the port,the maximum heap load should be controlled and the stacking yard should be evenly paved in the operation stage so as to reduce the uneven settlement of the filling area.