A New Stress–Strain Curve Prediction Model for Moraine Soil Under Freeze‐Thaw Cycles Considering Mechanical Degradation Characteristics

ABSTRACT The stress‐strain behavior of remolded moraine soils is highly sensitive to freeze‐thaw (F‐T) cycles. However, studies on the evolution of the stress‐strain curve and microstructure in remolded moraine soils under F‐T cycles remain limited. To address this gap, a comprehensive experimental program was conducted that included F‐T cycle tests, triaxial shear tests (TST), and micro‐CT scanning to examine the influence of F‐T cycles on a remolded moraine soil from Linzhi City, Xizang. In addition, a novel Duncan‐Chang‐Jiang‐Lu (DC‐JL) model has been proposed in this study to fit and predict stress‐strain curves. The results show that F‐T cycles cause a marked reduction in shear strength ( TSS ) and the initial average elastic modulus ( E ₀ ) following softening and a hyperbolic bulge failure mode. TSS decreases by 12%∼30%, and E ₀ decreases by 30%∼45%. The DC‐JL model reliably predicts stress‐strain curves for any F‐T cycle within the experimental range ( N = 0–20) using results from N = 0, 2, 5, 10, and 20 cycles. Furthermore, the residual strength provided by the DC‐JL model closely matches the experimental data. F‐T cycles significantly impact mechanical behavior by deteriorating the internal microstructure, increasing micro‐porosity (from 14.25% to 18.69%), and leading to the formation of numerous cracks. The findings of this study are not only valuable for a better understanding of freeze‐thaw degradation in moraine soils but also for assessing long‐term stability using the proposed new model.