Evaluation of Instrumented Preloading with PVD in Deep Soft Bandung Lacustrine Soil

Bandung Lacustrine Clay displays distinctive characteristics, including a void ratio exceeding 5 and significant compressibility extending up to 25 m in depth. Soil improvement at this site occurred in two stages: preloading in 2017 and preloading with Prefabricated Vertical Drains (PVD) in 2022. An array of instruments, such as settlement plates, extensometers, vibrating wire piezometers, inclinometers, and CPTu, were employed for instrumented soil improvement to measure compression and study the behavior of the soft lacustrine clay layer under embankment loads. The first stage of consolidation proceeded rapidly without PVD due to the high void ratio, while in the second stage with PVD, consolidation took just 2 months. Lacustrine clay exhibited significant immediate settlement. Creep initiated when the degree of consolidation fell below 80%. Overall, preloading proved effective in mitigating the creep issue.