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Numerical modelling of vacuum suction distribution and its effects in ground improvement with PVD vacuum consolidation

Prefabricated vertical drains (PVDs) with vacuum suction have helped to shorten the con-solidation time significantly in ground improvement projects. This method is claimed to be more effective and economical in consolidating deep soft clay layers. However, recent research has shown that the vac-uum suction applied to PVD near the ground surface may not penetrate the full depth (i.e. along the full length) of the PVD and the actual effects of the vacuum suction on the consolidation of the clay are not clearly understood. In this paper, an innovative approach is presented to model the vacuum suction distri-bution along the PVD using Finite Element (FE) modelling. Complex vacuum distributions, close to ellip-tical in shape is modelled and validated against field performance monitoring data. Moreover, the effects of this vacuum distribution on the deformational behaviour of the soft clay are also discussed.