Numerical Modeling of Prefabricated Vertical Drain with Vacuum Consolidation Technique

This paper addresses the issue of the latest analytical method when tackling a vacuum consolidation problem in a ground improvement project using prefabricated vertical drains (PVD) and the necessity of using numerical simulation. This paper aims to introduce a matching scheme to derive appropriate soil and drain properties in analytical solution and numerical modeling (axisymmetric and plane strain conditions). The scheme started with the analytical solution with a trial process of matching the predicted and measured settlements. The derived parameters are then adopted in the numerical modeling. Depending on the scenarios considered including axisymmetric and plane strain conditions, some parameters such as permeability need to be adjusted to have the best fit in the settlement estimation. In situ monitoring data from a case history of a road construction project in Vietnam was adopted in the back-analysis to demonstrate the application of the proposed matching scheme. In addition, the effectiveness of soft ground treatment by prefabricated vertical drain is evaluated in numerical modeling and field measurement. Very good agreement in settlement behavior and the effective stress variation between numerical simulation and field measurement have illustrated the proposed matching scheme's appropriateness.