Abstract:

The process of drainage consolidation is usually weak and construction delivery is longer as the filling will clog the plastic drainage slab in classical vacuum preloading. Thus, a new vacuum preloading with air pressure boosted was introduced to treat soft soils of a certain railway station. To evaluate this effect of new methods, settlement and pore water pressure of the foundation are monitored and compared in the period of reinforcement. It shows that settlements in the 3rd and 4th regions where reinforcement of vacuum preloading is used are much greater than in the 1st region where normal vacuum preloading is used. Moreover, the duration time of pore pressure dissipation is shorter in above areas. The settlement of area with plastic drainage slab in space of 1.0 m is about more 30% than that in space of 1.2 m. So the mechanism of this new technique is that the boosting from ram pipe speedups drainage and overcomes the jam of mud in plastic slabs.

Key words: vacuum preloading with air pressure boosted, mechanics of soft ground stabilization, foundations, settlement, pore water pressure