Strength and Fractal Damage Characteristics of Cement-Coal Slag Stabilized Soil under Freeze-thaw Cycles

Triaxial compression tests and CT scanning experiments were conducted to study the variation law of the mechanical characteristics of cement-coal slag stabilized soil (CCSSS) and divide the meso-structure of the CCSSS into regions based on the distribution of CT values. The evolution law and fractal characteristics of the meso-structure in the damage zone under freeze-thaw cycles were analyzed, while the relationship between the macroscopic mechanical parameters of CCSSS and the morphology of the damage zone was established by fractal characteristics. The results showed that with an increase in the number of freeze-thaw cycles, the shear strength of CCSSS exhibited an exponential decay pattern. The freeze-thaw cycles significantly impacted the strain energy density and cohesion of CCSSS, while the change in internal friction angle is insignificant. As the number of freeze-thaw cycles increases, the damaged area of CCSSS gradually expanded, with the effects of the initial 5 freeze-thaw cycles being more pronounced. Moreover, with an increase in water content, the damaged area of CCSSS showed an accelerating growth trend. There is a strong negative linear correlation between the fractal dimension of the damaged area and shear strength, accurately reflecting the damage caused by freeze-thaw action to the soil.