Numerical analysis of oversized deep soft foundation improved by plastic drainge plates combined with surcharge preloading

A series of two-dimensional numerical analyses are carried out to investigate the behaviors of soft soil foundation at Shanghai Pudong International Airport by means of the finite element software Plaxis. Both the soft soil model and the Mohr-Coulomb model are used to simulate the staged construction process involving installation of plastic drainage plates, layered filling and surcharge preloading and unloading. The numerical and field monitoring results are compared to investigate the behaviors of soft soil foundation improved by plastic drainage plates together with surcharge loading method. It is shown that it is necessary to take the creep of soft soils into consideration for predicting settlements of thick soft soil layers improved by using this method.