Strength and Deformation of Unsaturated Soil Contaminated with CH₃COOH

Unsaturated contaminated soil from domestic sources has a significant impact on engineering construction. Taking unsaturated CH₃COOH contaminated clay as the research object, unsaturated triaxial tests under different matrix suction and different net confining pressure were carried out, and the strength parameters and strength prediction formula were obtained. The prediction results of unsaturated soil strength of Fredlund Xing soil water characteristic curve model and Van Genuchten soil water characteristic curve model were compared. Scanning electron microscopy (SEM) was used to observe and analyze the characteristics of the microstructure of contaminated clay. It shows that the matric suction of unsaturated soil can increase the cohesion and internal friction angle of unsaturated soil, and the increase is linear, which conforms to the bivariate shear strength relationship. As the suction of the matrix increases, the stress–strain curve gradually changes from strain softening to strain hardening. The prediction result of unsaturated soil strength based on Fredlund-Xing soil water characteristic curve model is better than that based on Van Genuchten soil water characteristic curve model, and the smaller the confining pressure and the greater the matrix suction, the more accurate the prediction result.CH₃COOH dissolves minerals and hard iron compound minerals in the soil, reduces soil strength and increases soil deformation.