Abstract: Usher model, as a model for general prediction of petroleum economy and resources, is used to predict roadbed settlement based on the process of roadbed settlement under the linear or approximately linear loading and the characteristics of the Usher curve. Through analyzing the differential equations of the Usher model, it is pointed out that the Logistic model and Gompertz model used for settlement prediction of foundation at present are two simplified patterns, but to the actual condition, the applicability of the Usher model is better. The calculation methods of the parameters in Usher model are expounded; and they are applied to the calculation for an example; the comparison of results between the three models shows a good agreement, which indicates that the Usher model advised in predicting the subsoil settlement is reasonable. The example also indicates that the Usher model has a higher forecast accuracy and may be adopted in engineering practice.

Key words: settlement prediction, Usher model, Logistic model, Gompertz model