The numerical investigation of the efficiency of vacuum preloading in weak clay soil treatment (a numerical study)

Vacuum preloading is a highly effective method for acceleration of soil treatment systems in weak clays but unfortunately till now this efficient method is completely unknown in Iran. Since both in south and north of Iran there is numerous offshore structures under construction, this method can be used to accelerate the consolidation process in an economic way. This method mostly used in conjunction with prefabricated vertical drains (PVD) and surcharge embankments and in combined system the height of the embankments reduced drastically as a result of applied vacuum pressure. In this paper, a case study that is Mahshahr decanter in south part of the Iran where surcharge and PVDs were used, is investigated as a case study to illustrate the effectiveness of vacuum preloading in such projects. After verification of the model, the vacuum pressure 30, 60 and 75 kpa were applied to the system in three cases as: 6 m surcharge, 3-meter surcharge and the case with no surcharge preloading. Base on the results, applying vacuum preloading significantly increased system overall efficiency. The case with 3 m surcharge and 30 kpa vacuum pressure found to be the optimum case for this project. The finding of this literature can be used in similar projects.