干湿循环下工业废渣固化淤泥破碎重塑土渗透特性及微观机制OA

Crushed and remolded solidified sludge was prepared using an industrial waste-based curing agent.Permeability tests were conducted under different curing agent contents and wet-dry cycle numbers.The evolu-tion of permeability and microstructural mechanism of crushed and remolded soil under wet-dry cycles were analyzed by scanning electron microscopy,X-ray diffraction,and low-field nuclear magnetic resonance.The results indicate that the permeability coefficient of soil increases with the increase of the wet-dry cycle number.Provided that the permeability coefficient satisfies engineering requirements,higher curing agent content leads to greater formation of C-(A)-S-H cementitious gels and AFt crystals,denser pore structure,and stronger re-sistance to wet-dry deterioration,resulting in a slower increase in permeability.The pore structure of crushed and remolded soil is mainly composed of medium pores and large ones.An increase in the curing agent content can increase the volume fraction of medium pores and decrease that of large pores,whereas an increase in the wet-dry cycle number leads to opposite changes.The permeability coefficient exhibits a slow-rapid increasing trend with the increase of the volume fraction of large pores.When the wet-dry cycle number is fewer than three,the volume fraction of large pores increases but effective connectivity is not formed,resulting in a slow increase in permeability.When the wet-dry cycle number exceeds three,the volume fraction of large pores in-creases and pores become interconnected,leading to a rapid increase in permeability.In addition,a good lin-ear positive correlation is observed between the permeability coefficient and the volume fraction of fractures.