Abstract: The vacuum preloading drainage consolidation method is used in Shanghai a project. In the project, field tests are conducted in areas No.28 and No.30. The variation rule of surface settlement, horizontal displacement, groundwater level, pore-water pressure, and especially the relationship between vacuum and pore-water pressure are studied by means of field monitoring in the process of vacuum preloading. Two rows of mixing piles including 5% of cement are used as a sealing wall in the project, which play an important role in seepage control. Compared with traditional mixing piles, the two rows of mixing piles can avoid the disadvantage of low foundation strength at the location. It is shown that the vacuum preloading method has achieved good results in Shanghai, and the method is worth popularization.

Key words: field test, monitoring, sealing wall, vacuum preloading