Effects of temperature circulation on dredged sludge improved by vacuum preloading

Abstract Vacuum preloading is an effective and common method used for clay soil improvement. However, the smear zone generated by the installation of prefabricated vertical drain (PVD) hinders additional efficiency improvements. PVD combined with heat is applied to overcome this problem. This study presents a series of model tests conducted on clayey soil improved by vacuum preloading with different rectangular-wave temperature circulation modes to investigate the effects of cyclic temperature on vacuum consolidation. During the test, the settlement, pore-water pressure, and drainage were monitored. The degree of consolidation was analyzed to evaluate the effectiveness of this method, and the coefficient of energy consumption was used to quantify the energy consumption at different cyclic temperature modes. The results indicated that the rectangular-wave temperature circulation mode of 30–75–30 °C was the most effective. The results of this study contribute substantially to the state of knowledge regarding the cyclic temperature effects on dredged slurry performance subjected to vacuum preloading. Concurrently, a novel approach is introduced for the determination of the optimal soil consolidation.