Abstract: The low bearing capacity of coastal soft soils in China prevents their direct use as foundations for engineering construction.Additionally,the utilization rates of industrial waste materials such as slag and carbide slag remain low.In response to the demand for high-quality development,this study investigates the macro-mechanical properties and micro-structural development mechanisms of geological polymers derived from slag and carbide slag for the stabilization of coastal soft soils.Through response surface methodology and numerical analysis,the optimal proportions of slag,carbide slag,and sodium silicate were determined to be 16.8%,6.9%,and 3.6%,respectively,leading to the formulation of the KDG curing agent.Unconfined compressive strength,water stability,dry-wet cycling,and freeze-thaw cycling tests were conducted to compare the curing effects of KDG with that of cement under various conditions.At both 7 and 28 days,the KDG solidified soil demonstrated superior compressive strength,toughness,water stability,resistance to dry-wet cycling,and freeze-thaw cycling compared to cement solidified soil.XRD and SEM analyses revealed that the hydration products of KDG solidified soil at 7 days primarily consisted of fibrous calcium silicate hydrate (C-S-H),which evolved into a three-dimensional network structure by 28 days,effectively filling internal voids and enhancing the mechanical properties.The KDG curing agent significantly improves the stabilization of soft soils while increasing the utilization of waste materials,aligning with sustainable development principles.This research holds significant implications for the treatment of coastal soft soil foundations and the use of premixed stabilized soils based on soft materials.