Abstract: The vacuum surcharge method is an economical, environmentally friendly, low carbon emission soil improvement method. This method is carried out through the vacuum pump out the air in the soil, the negative pressure formed in the vacuumed soil can suck the gravity water out through prefabricated plastic drains, sand drains and other vertical drainage system, as well as sand cushions and other horizontal drainage system. Therefore, the soft soil will be consolidated, and compression settlement will occur. In order to accelerate the construction progress, the combined prepressing of covering loading and vacuum loading is often used, namely the vacuum-covering combined surcharge method. The case history of the deep soil improvement in a wastewater treatment plant in Wuhan is presented in this paper. The vacuum-covering joint surcharging method in a deep soil improvement is introduced. The engineering and geological conditions, the design aspects of soil improvement partition, drainage system and construction process, as well as the construction monitoring, are also presented in the paper.

Key words: Vacuum Surcharge Method, Vacuum and Water Coving Joint Surcharging Method, Soil Improvement