Consolidation of clay slurry under different vacuum preloading conditions

Eight laboratory model tests were conducted to evaluate the effectiveness of vacuum preloading method under different loading systems, using different types of drain and different types of soils respectively. The model tests show that the preloading system using membrane is more effective in treating soft clay material than that without membrane, given the same vacuum pressure applied. This is partially due to the additional application of vacuum pressure through the horizontal drain blanket. However, such an additional benefit may become insignificant when the compressible soil to be treated is thick. The model tests also show that the use of circular drain does not seem to offer much benefit over the use of band drain.