Laboratory and field experimental study on efficiency of vacuum preloading–flocculation–solidification combined method for slurry-like mud treatment

A new integrated method, i.e., vacuum preloading–flocculation–solidification combined method (VP-FSCM), has been developed for treatment and recycling of slurry-like mud (MS). However, due to the insufficient solidification caused by the decay of vacuum pressure among other factors, the superiority of VP-FSCM under various mixing conditions and the distribution of engineering properties of VP-FSCM-treated MS are not well understood especially at the field pilot scale. In this study, a series of laboratory experiments are performed first to identify the influence of equivalent initial water content (w_ei) and binder content (w_c) on the superiority of VP-FSCM over the conventional pure cement solidification method (PCSM), and some field pilot experiments are then conducted to further demonstrate the solidification efficiency of VP-FSCM and characterize the spatial distribution of strength of VP-FSCM-treated MS. The results indicate that VP-FSCM outperforms PCSM in treatment and utilization of MS, with the strength of VP-FSCM-treated MS being approximately 2.24 times larger than that of PCSM treated MS under the equivalent circumstance at the field pilot scale. In addition, the strength of VP-FSCM-treated MS increases substantially with the decrease in distance away from the central axis of a prefabricated horizontal drain and tends to show higher spatial variability than that of PCSM treated MS.