Abstract: In order to investigate the practical effect of electroosmosis method in reinforcing dredger-fill silt and in the meantime to understand the influence of electrode arrangement on the reinforcement effect, we performed three types of test based upon specific dredger-fill projects. These tests include vacuum preloading without sand cushion combined with electroosmosis (hereafter referred to as S1), vacuum preloading without sand cushion combined with electroosmosis grouting (S2), and vacuum preloading without sand cushion combined with conductive drainage plate (S3). Moreover, both in S1 and S3, the electrodes were arranged in parallel and dislocated intervals, respectively. Thus, in total we conducted five tests for comparative study. The test data shows that the bearing capacity and shear strength of the foundation strengthened by the five tests have been greatly improved, and the water content of the soil has been greatly reduced. The results demonstrate that the effect of S1 is better than that of vacuum preloading without sand cushion, with shorter construction period. The effect of S2 is better than that of other test forms. Electroosmosis method combined with vacuum preloading without sand cushion could effectively remedy some shortcomings of vacuum preloading without sand cushion, and can be applied to consolidation of dredger-fill foundation with special requirements for bearing capacity and duration.

Key words: dredger-fill silt, vacuum preloading combined with electroosmosis method, electrode, field test, reinforcement effect