This paper utilizes industrial wastes, including slag powder, desulfurized gypsum, fly ash, and construction waste, to solidify municipal sludge and develop a new type of landfill cover material. To investigate the durability of solidified sludge under wet-dry cycles, this study systematically analyzes its mechanical properties-such as volume shrinkage rate, unconfined compressive strength, and permeability coefficient-along with microstructural characteristics like pore structure, micro-morphology, and hydration products. In addition, the impermeability of the solidified sludge cover under va...