ABSTRACT
The soil model consisted of three layers. The top sand layer functioned as a surcharge as well as a drainage layer. The bottom sand layer also functioned as a drainage layer. The soft clay layer was placed in between the two sand layers. To prevent inflow of water into the soil model, the entire soil model was covered by a membrane with a holder as shown in Figure 3. The transducers went through a sealing cable fitting attached to the membrane. To simulate the contribution of the total stress of water above the membrane in underwater vacuum preloading, a layer of water of about 50 kPa (prototype scale) was added. To generate large vacuum pressure, the inlet to the vacuum chamber was set 100 mm below the clay surface to provide a potential-100 kPa pressure on the clay surface with the assistance of vacuum pressure.
