Determination of lateral impact zone under vacuum consolidation method: Numerical modelling and novel analytical prediction method

Prediction of the lateral displacement and the associated impact zone under the coupled effect of vacuum-surcharge loading remains significant challenges in design of vacuum consolidation method (VCM). Following an earlier field study by the authors, where extensive investigations on lateral displacement in VCM sites were conducted, this paper details development of numerical modelling and proposes a novel analytical method. Finite element method is adopted to reproduce the test embankments with close validation with field data, followed by a comprehensive parametric study on the influence that varying the vacuum-surcharge load ratio and distance from the embankment can cause on the lateral displacement. The numerical results reveal the nonlinear relationship between the load ratio and lateral displacement of soil, allowing for assessment of the lateral impact zone. By forming empirical correlations between the displacement and load ratios, the study proposes a novel analytical procedure to estimate the lateral displacement according to distance from the embankment toe. The proposed method is validated against six different case studies, demonstrating its great reliability and robustness in predicting spatial lateral displacement. This study enables the lateral impact zone to be determined based on lateral displacement profile, giving a simple yet accurate approach for safe and cost-effective design and construction planning.