Abstract: The diatomite is a kind of strong structural soil, which has small density, large porosity, and high water absorption rates of dry rock. The shear strength of natural diatomite is large, but the structural strength lost occurs when the diatomite is disturbed by the external disturbance or weathering; so the diatomite slope is easily destroyed in the performance of landslide; thus to study the mechanical properties under large deformation is necessary. Using the characteristics of ring shear apparatus can study soil shear strength variation in a larger shear displacement conditions. this paper makes ring shear strength test study of the remolding diatomite, to obtain the stress displacement curves under different vertical pressures, which indicate that the remolding diatomite is of typical strain softening. According to the ring shear test results the remolding diatomite’s, shear strength and residual strength are obtained, and the soil mechanical properties are analyzed from the material composition and microstructure characteristics of the remolding diatomite, so as to provide reasonable parameters for diatomite landslide analysis and disaster prevention and control.

Key words: remolding diatomite, ring shear test, shear strength, landslide, residual strength