Abstract: In this paper the axial stress-strain relation, the axial rheological deformation and radial rheological deformation of soft sandstone are measured by RLW-2000M triaxial rheological testing machine in an attempt to investigate the influence of frequency and amplitude of dynamic loading on sandstone’s rheological properties. Moreover, the expression of damage degree with axial strain as damage variable is derived, and the effect of each factor on damage degree is studied. Research results indicate that axial and radial deformations increase with the passage of time, and the hysteresis curve changes from sparse to dense under the action of dynamic loading. The increases in axial and radial deformations intensify with the climbing of dynamic loading amplitude, but attenuate with the rising of frequency. In addition, after an abrupt change, the damage degree of specimen tends to be stable and increases with the climbing of dynamic loading amplitude. The research results will provide scientific basis for us to uncover the rule of rheological damage evolution of sandstone under the action of dynamic loading.

Key words: sandstone, rheological damage, frequency of dynamic loading, amplitude of dynamic loading, rheological curve