Strength deterioration model of remolded loess contaminated with acid and alkali solution under freeze-thaw cycles

The development of seasonal frozen region made the problems of soil pollution more complex. The shear strength characteristics of remolded loess are throughout investigated by direct shear tests with different concentrations of acid and alkali solution and are illustrated by the phenomena of the strength deterioration, which takes the freeze-thaw cycles into consideration. The experiment results show that the freeze-thaw cycle will cause the strength deterioration of soil, although the strength of soil has increased due to the pollution. The different type and adding order of solution will have a different impact on the strength deterioration when soil is under the freeze-thaw cycle. Moreover, the deterioration coefficient of internal friction angle (K-phi) does not change regularly with the increase of the freeze-thaw cycles, and it fluctuates up and down in a small area which does not change a lot. The deterioration coefficient of cohesion (K-c) changes regularly with the increase of the freeze-thaw cycles under all polluted conditions. The type, the adding order, and the concentration of solution all have an effect on the K-c. Strength deterioration model of remolded loess contaminated with acid and alkali solution under freeze-thaw cycles accords with an exponential function.