Reasonable application range of flocculation–solidification combined method in treatment of hydraulically dredged mud slurry

Abstract

An improved method, i.e., flocculation–solidification combined method (FSCM), has been developed for building a working platform more efficiently at the surface of newly reclaimed ground filled with hydraulically dredged mud slurry at extra high water content (EHW-MS). Previous experimental results have demonstrated the significant superiority of FSCM over conventional pure cement solidification method (PCSM) under some application conditions. This study focuses on further clarifying the reasonable boundary for the application conditions, i.e., identifying the reasonable application range, of FSCM in EHW-MS treatment. A number of laboratory experiments are performed to characterize the deposition and strength gain behavior of FSCM or PCSM treated EHW-MS samples with various values of the equivalent initial water content (w ei) and Atterberg limits. The deposition and strength characteristics resulting from FSCM and PCSM are then compared comprehensively to illustrate the influence of w ei and Atterberg limits on the superiority of FSCM over PCSM. Results indicate well that FSCM shows more significant superiority over PCSM with the increase of either w ei or Atterberg limits, and plastic limit > 14 (or liquid limit > 23) and w ei > 232% can be considered as the reasonable application range of FSCM in EHW-MS treatment, within which the solidification efficiency of FSCM is at least 1.20 times higher than that of PCSM.