English：

To investigate the internal structural deterioration characteristics and the evolution laws ofphysical and mechanical properties of loess⁃based cement soil under freeze⁃thaw cycles, loess⁃basedcement soil materials were prepared based on excavated waste loess. Orthogonal experiments and freeze⁃thaw cycle tests were conducted. The microstructural deterioration characteristics of the materials underdifferent freeze⁃thaw cycles were obtained through scanning electron microscopy. Precision electronicscales, triaxial shear testers, and non⁃metallic ultrasonic detectors were used to measure the mass growthrate, uniaxial compressive strength, and relative elastic modulus, respectively. Based on the rangeanalysis method, the influence of cement content, fly ash content,water⁃cement ratio, and compositewater reducer content on the physical and mechanical properties of the materials was systematicallyanalyzed. The results showed that with the increase in the number of freeze⁃thaw cycles, themicrostructure of loess⁃based cement soil gradually deteriorated; different components had significanteffects on its frost resistance. Among them, the mass growth rate was negatively correlated with cementcontent, fly ash content, and composite water reducer content, but positively correlated with water⁃cement ratio; compressive strength and relative elastic modulus increased with the increase in cementcontent, fly ash content, and composite water reducer content, but decreased with the increase in water⁃cement ratio.