Strength improvement of high organic dredged soil by solidification/oxidization synergistic method

Abstract

Soil organic matter (SOM) has always been one of the critical factors affecting the solidification of dredged soil. This study proposes a solidification/oxidization synergistic (SOS) method for treating high organic DS. Three solid oxidants, i.e., sodium persulfate (PS), sodium percarbonate (PC), and potassium ferrate (PF), were added to DS in cooperation with cement, respectively. The results show that all three oxidants showed a good degradation effect on SOM and had the optimal dosage, which increased gradually with cement content (Ac) when used with cement. Under the optimal dosage of oxidant and Ac = 15%, PS and PC can improve the unconfined compression strength (UCS) of cement-solidified DS (CDS) at 60 d of curing to nearly 4 times compared with that without oxidant, while PF can only increase the 60d-UCS to 1.5 times. In addition, the influence mechanism of different oxidants on the UCS of CDS was analyzed based on microscopic tests, proving that the three oxidants can not only degrade the SOM in CDS but also participate in the hydration reaction of cement. It is feasible to use proper amounts of PC and PS in combination with cement to solidify high organic soil.