| There are many unfavorable engineering characteristics for soft soil foundation, such as low bearing capacity, high settlement and long consolidation time. The potential settlement after construction of the freeway which constructs on the soft soil is a big damage for transportation. So it is necessary to predict settlement exactly. It is very important to control construction progress and organize construction in theory and actuality based on probing the regularity of soft soil foundation deeply , forecasting the deuteric settlement with actual limited settlement data by reasonable forecast model and methodology.In this paper, deformation properties, stress-strain relation and settlement mechanism are introduced firstly through researching the conception, classification and engineering characteristic. And then, all kinds of soft ground prediction methods are introduced and analyzed in detail. Finally based on deformation observation for the project of Liang-Ji Canal Bridge on the highway for more than one year, the settlement of five time point after 300 days is predicted by many different forecast methods from the actual settlement data. The ideal forecast result proved the applicability of every prediction method mentioned in this paper.By analysis of prediction result, the conclusion can be obtained that the most ideal prediction result is the combination forecasting and next come the neural network method, the hyperbola method, and the index curve method is the worst one. The calculated initial time should be on the convergent settlement rate segment for empirical formula method. Weakening buffer operator weakens the impacted interference for gray theory method. BP neural network has strong self-study ability and some value in engineering application. The precision of combination prediction model based on forecasting effective measure is better than that of the single models and the combination prediction is optimal for this project.
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