为了研究冻结硫酸钠粉质黏土的变形规律和强度特征，在1 MPa围压下，对-2、-6、-10 ℃三组温度下不同硫酸钠含量的粉质黏土进行负温三轴剪切试验研究。基于实验数据，计算了冻结硫酸钠粉质黏土的切线模量，研究了轴向应变与偏应力的非线性关系，推导了试样的p-q平面强度准则，提出了冻结硫酸钠盐粉质黏土强度公式，建立了含参数的冻结含盐粉质黏土的修正Duncan-Chang本构模型，并拟合了相关参数，验证了模型精度及适用性。结果表明：试样的偏应力在应变后期趋于稳定，处于向应变硬化过渡的阶段，切线模量E随含盐量的增加呈现先减小再增大再减小的变化规律，切线模量E变化幅度较小，p、q呈明显的线性关系，在0 ℃至-15 ℃温度范围内，修正Duncan-Chang本构模型对含盐量小于2.5%的冻结硫酸钠粉质黏土强度具有良好的预测效果。

In order to study the deformation law and strength characteristics of frozen sodium sulfate silty clay， negative temperature triaxial shear tests were carried out on silty clay with different sodium sulfate contents in the temperature range of -2， -6， -10 ℃ under 1 MPa confining pressure. Based on the experimental data， the tangential modulus of frozen sodium sulfate silty clay was calculated， the nonlinear relationship between axial strain and deviational stress was studied， the p-q plane strength criterion of sample was derived， and the strength formula of frozen sodium sulfate silty clay was proposed. The modified Duncan-Chang constitutive model of frozen salt-bearing silt with parameters was established， and the relevant parameters were fitted to verify the accuracy and applicability of the model. The results show that the deviational stress of the sample tends to be stable at the later stage of strain hardening， and the tangential modulus E of the sample at negative temperature decreases first， then increases and then decreases with the increase of salt content. The tangential modulus E has changed in a small variation range and p-q shows an obvious linear relationship. In the temperature range of 0 ℃ to 15 ℃， the modified Duncan-Chang constitutive model has good prediction effect on the strength of frozen sodium sulfate silty clay with salt content less than 2.5%.