Consolidation behavior of Tianjin dredged clay using two air-booster vacuum preloading methods
Huayang Lei, Yao Hu, Jingjin Liu, Xu Liu, Chenyuan Li
Abstract
This paper presents model tests (macro aspect) and microstructure tests (micro aspect) for investigating the consolidation behavior of Tianjin dredged clay using the prefabricated vertical drain air-booster vacuum preloading (PAVP) and tube air-booster vacuum preloading (TAVP) methods. The mechanism of air-booster vacuum preloading (AVP) using a spring-like system is explained. The main difference between these two methods is the air-boosting equipment. A new anticlogging air-booster prefabricated vertical drain (PVD) is used in the PAVP technique and a self-designed air-booster tube is used in the TAVP technique. In the model tests, a comparison of the variables that are monitored during reinforcement (vacuum pressure, surface settlement, water discharge, and pore-water pressure) and after reinforcement (water content, dry density, and vane shear strength) is conducted. The results indicate that the consolidation behavior of Tianjin dredged clay using the PAVP method is better than that using the TAVP method. PAVP more efficiently mitigates the issue of water-draining PVD clogging and significantly accelerates drainage consolidation. In addition, in the microstructure tests, a comparison of the variables that are monitored after reinforcement (via scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP)) is conducted, and the results further explain the model test results.