The case study of vacuum preloading to reinforce soft soil foundation for expressway

And the degree of vacuum under-membrance reached 60 kPa. In the 1980’s, the research for the method of vacuum preloading developed in China. The research included studying on the mechanism, updating the equipment, improving the effect of reinforcement and promoting the using of the method. Qian (1981) reported the application of vacuum preloading method to reinforce the soil foundation in Tianjin, and the degree of vacuum under-membrance reached 80 to 95 kPa.