Abstract: Laboratory tests have been carried out for simulating dredged-slurry treatment combining air-booster and conventional vacuum preloading methods. Settlement plate, micro pore water pressure transducer and miniature vane shearing instrument are adopted for monitoring the settlement, the pore pressure dissipation and the soil strength during the test. The tests results demonstrate that the air-booster vacuum-preloading method can significantly improve the soil strength, pore-water pressure dissipation and settlement. In particular, the real-time responses of pore-water pressure during the air-pressurizing process have been obtained that, in combination with the numerical simulations, help derive the reinforcement mechanism of the air-booster vacuum preloading method, which involves using micro cracks generated by splitting soil between the booster tube and PVD using the pressurised air. Those cracks improve the soil permeability, and have lasting effect even after air pressuring ceased.

Key words: air pressurizing, vacuum preloading, reinforcement effect, reinforcement mechanism