Change of mechanical behavior between solidified and remolded solidified dredged materials

Roller-compaction technology is generally employed in dredged material (DM) solidification projects in China. However, the mechanical behavior of remolded solidified dredged material (RSDM) has not been clear. In this paper, the stress–strain relationships, compressibility and strength characteristics of RSDM have been studied and compared with intact solidified dredged material (SDM). Ductile and brittle behaviors are observed for pre-yield and post-yield state of SDM, whereas all RSDM specimens show ductile behavior. The compression curve of RSDM is lower than that of SDM. The compressibility of RSDM is about three times higher than SDM at pre-yield, but less than SDM at post-yield. The yield stress of RSDM is about half that obtained for SDM. The strength of SDM only changes slightly in the pre-yield state, but it increases linearly with the increase of the consolidation pressure in the post-yield state. The strength of RSDM simply increases with the increase of the consolidation pressures. The unconfined compressive strength of RSDM is about 20% to 40% when compared with the compressive strength of SDM. The strength difference between SDM and RSDM decreases as consolidation pressure increases. The reasons for the mechanical differences may be attributed to the fact that SDM is a structured soil originating from strong cementation bonds, whereas, RSDM is not a structured soil.

Research highlights
► Compressibility of RSDM is larger than SDM in pre-yield state.
► Strength of RSDM is lower than that of SDM.
► Strength envelope of RSDM is a straight line, while SDM consists of bilinear lines.
► SDM is a structured soil, while RSDM not.