This paper presents a case history of the performance of a full-scale test embankment constructed on very soft clay deposit in middle part of China, near Wuhan. The embankment was constructed on prefabricated vertical drain (PVD) improved subsoil. The height of the embankment is 5.3m and construction time was about one year. The thickness of soft deposit with PVD-improved was 13 m. The PVDs were installed to a depth of 8.5 m with spacing of 1.5 m in a triangular pattern. To investigate the performance of this embankment construction and the effect of PVDs, a comprehensive instrumentation program was conducted during construction. Field observation included excess pore pressure, ground settlement, and lateral displacement. Analysis of field data indicated that the ground settlements were small for a long construction and low height. This construction in general exhibited different behaviours than other projects because of his relatively long construction and low height. This project serves as a special case study and provided insights into the design and s of a long duration construction.