Experimental study of PVD-improved dredged soil with vacuum preloading and air pressure

The PVD-vacuum method is the main method used to treat dredged soil, but sometimes it cannot completely meet engineering needs due to the limitations of vacuum pressure. Therefore, based on the traditional PVD-vacuum method, a method of air pressure combined with vacuum preloading is proposed in this paper. The air pressure is transmitted into the dredged soil by using an impermeable and flexible membrane airbag embedded in the dredged soil. A comparison of the traditional PVD-vacuum method and the combination of air pressure and vacuum preloading is investigated by the model test. The data of the settlement and water discharge during the test are monitored. After the tests, the water content and shear strength at different positions are measured. Finally, a method for calculating the volume change of dredged soil is proposed, and the results of the test are used to prove the correctness of the proposed method. •A new method that treated the dredged soil by using a combination of the PVD-vacuum preloading and air pressure is proposed.•The model test results show that the new method does better than the traditional method on the efficiency of water discharge.•The prediction method of water discharge for the treatment of the PVD-vacuum preloading and air pressure is proposed.