Consolidation characteristics of ultra soft soil foundation by vacuum preloading based on digital image technology

This study investigates soil samples from Wenzhou, Taizhou and Ningbo regions with different initial water contents. Indoor vacuum preloading model tests combined with particle image velocimetry (PIV) technology are used to analyze the differences in consolidation characteristics of the soil samples during the reinforcement process. The PIV technique revealed the mechanism of the consolidation differences. The results show that as the clay content and initial water content increase, the soil particle displacement increases, the permeability coefficient of the clogging zone significantly decreases, and the dissipation rate of pore water pressure diminishes. Additionally, the effect of particle gradation on the formation of consolidation differences in the clogging zone and soil is more pronounced. This research provides a theoretical basis and technical support for vacuum preloading reinforcement of soft soil foundations and offers significant guidance for engineering design and construction.