Abstract: A creeping landslide shows a deformation response of long-term and small-scale, the evolution and stability of which are controlled by the creep response of sliding-zone soil. The Majiagou landslide, a typical creeping landslide in Three Gorges reservoir region, is selected as a case. A series of large-scale triaxial compression tests is conducted on the undisturbed specimens of sliding-zone soil to reveal the creep laws of sliding-zone soil under different confining pressures and stress levels. On this basis, the difference between long-term strength and conventional strength of the soil is determined by the isochronous curves. The results show that the sliding-zone soil of Majiagou landslide has steady creep characteristic, and the creep process can be divided into attenuation creep stage and constant speed creep stage. And the deformation tendency of sliding-zone soil is similar to the macroscopic deformation of the landslide. The absolute creep displacement and the strain rate of constant speed creep stage are positively correlated with the axial stress. While the duration of the attenuation creep stage increases linearly with the shear stress level. The long-term cohesion and the long-term internal frictional angle decrease by 24.8% and 22.4% respectively comparing with the conventional strength parameters.

Key words: creeping landslide, sliding-zone soil, triaxial creep tests, creep properties, long-term strength