Abstract:

In view of the problems such as the time of self-consolidation is long and the drain pipes are easy to clogged and consolidation will slow down gragually in practice, a grading vacuum preloading method is put forward, namely, vacuum preloading is imposed hierarchically, and simulation tests are carried out in laboratory. The test results show that the moisture content and the soluble salt content decreases gradually, the strength increases gradually during the consolidation process of dredger fill. The physical and chemical properties of dredger fill have been improved after the hierarchical vacuum preloading. At the same time, samples are tested by the mercury intrusion test which sampled from consolidation process and the pore distribution characteristics is analyzed by using fractal theory. It shows that the large size of pore will be compressed into more small pore with the increase of consolidation pressure and the variation of pore diameter distribution is changed from majority of large size pore (above 50%) into advantage of middle and small size pore, which are above 35% and above 35% respectively.

Key words: dredger fill, hierarchical vacuum preloading, mercury intrusion test, pore diameter, fractals