ABSTRACT
Sanjiadi old landslide in southern Gansu has taken place in a large-scale collapse in the foreside and formed long cracks induced by front traction in Wenchuan earthquake. This landslide will threaten the safety of 1732 people. Sliding zone soil is an important part of landslide, which plays a controlling role in its deformation and stability. The sliding zone soil of Sanjiadi landslide in South Gansu is low liquid limit clay, which is a typical sliding stratum. Rainfall has a significant softening effect on the sliding zone soil. The direct shear test, repeated shear test, and triaxial test are carried out by using the remolded soil samples of sliding zone soil with different water content. The results show that the stress-strain relationship of remolded sliding zone soil of Sanjiadi landslide is weak strain-softening when the water content is lower than the plastic limit, and strain hardening when the water content is higher than the plastic limit. The research results have an important practical significance for the evaluation of landslide stability and the optimization of prevention and control measures in this area.
