Improvement of soft clay by vacuum preloading incorporated with electroosmosis using electric vertical drains

Vacuum preloading combined with electroosmosis (VE) has a good drainage effect, but electric vertical drains (EVDs) as the drainage plate and electrode will cause the offset of water flow near the anode. Therefore, there is an alternate time for the optimal use of the two methods. In this paper, some macroscopic indexes were monitored through laboratory tests to explore the optimal alternate time of the two methods in the drainage stage, and the microscopic characteristics of the soil after treatment were explored through scanning electron micrographs and X-ray diffractometer tests. The results indicated that the alternating time of vacuum preloading and an electroosmosis time of 100 min can obtain a better drainage effect in the early stage. The vacuum preloading time of the alternate forms should be prolonged to 550 min during the later stages. The electroosmosis duration should not be too long, which was limited to 100 min in all the electroosmosis stages.