Experimental study on effects of vacuum loading modes on clogging of drainage board filtration membranes

The clogging of drainage board filtration membranes directly affects the effects of newly-dredged mud reinforced by the vacuum preloading drainage consolidation method, and the vacuum loading mode is one of the main reasons that cause clogging of drainage board filtration membranes. The drainage board filtration membranes with 5 kinds of different equivalent diameters are used to reinforce newly-dredged mud by controlling vacuum loading modes in laboratory. The surface settlement and vacuum degree at different depths of drainage board and soil are monitored during the tests, and the permeability of drainage board filtration membranes are tested after tests. The results show that for the vacuum load without gradient or with large gradient, the effects of vacuum preloading drainage consolidation method to reinforce newly-dredged mud are poor, and drainage board filtration membranes are easily clogged. The smaller the equivalent diameter of drainage board filtration membrane the more severe the clogging. The permeability of drainage board filtration membranes decreases after clogging that causes unfavorable effects on soil drainage consolidation. It is suggested that the equivalent diameter of drainage board filtration membranes should be larger, the vacuum load should be graded, and each vacuum load gradient shouldn’t be too large in engineering practice by using the vacuum preloading method to treat newly-dredged mud.