| Abstract: | The influence of strain history on rock specimen deformation during multi-level loading and unloading cyclic uniaxial compression creep tests is studied with a creep testing machine. An experimental data processing method for such creep tests is suggested. The correction formulas to determine the rheological model parameters are derived for the case when load relaxation is considered. Creep and relaxation tests under uniaxial compression on four types of rocks are conducted using an electronic hydraulic servo-controlled stiff testing machine. The creep and relaxation laws of the different rocks are compared. The complete stress–strain curves for red sandstone specimens are obtained at nine strain rates from 2.43×10−6 to 4.38×10−3/s. The effects of strain rates on rock strength and limit strain are discussed. Empirical equations to evaluate the strain rate dependence of rock mechanical properties are presented. |
