Abstract: At present, traditional sand well consolidation theory is adopted to calculate the consolidation characteristics of foundation treated by prefabricated vertical drains. The equivalent diameter of prefabricated vertical drain can be obtained by formulas including Hansbo’s perimeter equivalence and the equivalent reduction 0.75 times the perimeter in Code for Design of Sea Dike Project. But there is no unified understanding on it. In view of this, an analytical solution for the consolidation of foundation treated by prefabricated vertical drains is presented based on equal strain assumption. The rationality of this solution is validated by using ADINA. Furthermore, finite element method is adopted to build a 2D model of foundation treated by prefabricated vertical drains. The coefficient of permeability of drain tends to infinity in the model. It is found that the consolidation characteristics in the 2D model by Long & Covo (1994) are close to those by finite element method, yet with some deviations. Finally, the formula for calculating the equivalent diameter of 2D consolidation model of higher accuracy is given.

Key words: prefabricated vertical drains, consolidation theory, 2D consolidation model, equal strain assumption, equivalent diameter, well resistance factor