Influence of straw degradation on consolidation of dredged sludge under vacuum preloading Available to Purchase

Vacuum preloading with straw drainage has been used as an eco-friendly soil-reinforcement method to promote the consolidation of dredged sludge. In previous studies, the degradation of straw, an essential factor influencing dredged-sludge consolidation, has often been disregarded. In this study, laboratory tests were conducted to investigate the effects of straw degradation on the consolidation efficiency of dredged sludge. The vacuum level within the straw drainage was found to decrease with increasing degradation time, causing a reduction in water discharge and settlement. Consequently, the moisture content increased and the shear strength of the soil decreased. After 60 days of degradation, the water discharge and settlement decreased by 46% and 25%, respectively. The impact of degradation time was most significant during the first 15 days, which was when most straw degradation occurred. The average moisture difference in the first 15 days was 5.0%, whereas it was negligible (0.8%) from 45 to 60 days. The increase in organic matter content enhanced the Atterberg limits and hydrophilic properties of the soil. The findings of this study promote the engineering application of vacuum preloading with straw drainage and confirm it to be an effective and eco-friendly method for consolidating dredged sludge.