Unsaturated creep tests and empirical models for sliding zone soils of Qianjiangping landslide in the Three Gorges

Creep of sliding zone soils may cause significant displacement in large-scale landslides in the Three Gorges reservoir area. To investigate the effects of water on the soil creep behavior of the Qianjiangping landslide, a series of unsaturated triaxial creep tests on the sliding zone soils were performed. Based on the analyses of testing results, a new stress intensity incorporating matric suction was defined and an unsaturated Singh-Mitchell creep model was developed. Predicted results are in good agreement with the experimental results, which indicates that the established unsaturated model can reasonably simulate the effects of water on the soil creep behavior of the landslide. Finally, relationships between matric suction and the parameters of the model were analyzed. This study provides a calculation model and parameters for the evaluation of long-term stability of landslides under the influence of water.