Abstract: The integrated Zouma lake watershed treatment project is a pilot project of Ezhou Huahu airport project. The major work in this project is the ground improvement of soft cohesive soils and earthwork in the lake area. Large area of soft soils with an average thickness of about 7 to 8 meters and a maximum thickness up to 15 meters are deposited in the lake area. The post construction total settlement and differential settlement requirement criteria for the airport runway area are very strictive. Considering the construction cost and design requirements, the prefabricated vertical drains plus surcharging method was adopted as the ground improvement method. With the surcharge ratio between 1.35 and 1.45, the duration of surcharging was between six and ten months for achieving a degree of consolidation of 90% and a final rate of settlement less than 0.33 mm/day. The entire ground improvement duration was 33 months.

Key words: Soft Soils, Ground Improvements, Consolidations, Surcharging and Preloading