Sudden sedimentation of outer waterway is the crucial problem obstructing the development of Huanghua Port, which is the best coal export harbor of Shenhua Group. The construction and operation of the sand preventing dike have achieved an initial success. The paper analyses the stability and settlement of ground by three methods, i.e. theoretical calculation, experimental analysis and settlement observation, from which the direct conclusion is drawn. It puts the emphasis on the first method and makes verification by the experimental analysis,and gives the direct conclusion based on the observation data. The differences among the three methods, the mutual complementation and verification, as well as the function of geotextiles in the breakwater section on the soft ground are obtained.