Evaluation of Vacuum Preloading with Vertical Drains as a Soft Soil Improvement Measure

Abstract

Site condition and construction technology are described in detail, as well as the solutions to common problems encountered during the construction phase of such a project. A numerical model is established based on the case study and validated by the actual field measurements. The differences between modeled results and field measurements were 2.4-49.4%, which validate the accuracy of the numerical model. Settlement at the surface of soft soils was found to increase when the length and permeability coefficient of prefabricated vertical drains were increased, and decreased as the spacing increased. The estimated degree of consolidation at the final stage of vacuum preloading was 93.4% based on the degree of settlement, and 88.3% based on pore water pressure measurements. Thus, vacuum preloading with vertical drains was found to be an effective method by which to improve the strength of soft soils prior to construction on them.