Air-boosted vacuum preloading method for land reclamation with vertical drains: Numerical and analytical solutions

Abstract

As an emerging ground treatment technique, the air-boosted vacuum preloading method accelerates the consolidation process of soils with vertical drains and enhances the bearing capacity and stability of grounds. This improvement is achieved by augmenting the horizontal pressure differential between the drainage body and the surrounding soils. In the realm of existing theories, consolidation models are primarily established under the assumption of linear characteristics of soils. Nonetheless, for marine sedimentary soft soils characterized by high compressibility, the application of nonlinear consolidation theory becomes more appropriate. The well resistance effect of the drainage body over time is also considered in this study, and a comprehensive consolidation model tailored to soft soils with air-booster pipes and vertical drains is proposed. Subsequently, the analytical and numerical solutions for this consolidation model are derived, respectively. Comparisons are made with existing conventional linear consolidation models to substantiate the validity of the proposed consolidation model. This investigation delves into the influence of nonlinear compressibility and permeability of soils, variable well resistance, and drain spacing ratio, on consolidation behaviors. Particular emphasis is placed on the determination of the startup time for the air-boosted system. Finally, the proposed consolidation model is applied to the actual field prediction, affirming the accuracy and applicability of the developed consolidation model in practical soft soil treatments.