Study on Mechanical Properties and Fracture Characteristics of Composite Stabilized Saline Soil under Alternating Wet-Dry and Freeze-Thaw Cycles

Abstract

Saline soils in semi-arid and seasonally frozen regions are prone to deterioration due to evaporation, salt crystallization, and repeated wet–dry–freeze–thaw cycles, compromising engineering performance. This study investigates saline soil from Qian’an County, western Jilin Province, and evaluates a composite stabilization approach using sulfonated-free lignin, basalt fiber, and a hydrophobic polymer. Microstructural analyses and simulated environmental cycles demonstrate significant improvements in strength, durability, crack resistance, and long-term stability compared with untreated soil.