Creep property of mudstone under variable temperature and temperature correction

To study the mudstone buried in Yuncheng mine,a tri-axial compression creep test was undertaken,and the temperature in this experiment varied coincidently with the environment temperature. It was shown that the temperature has a great effect on the creep strain of mudstone,but has little effect on the creep rate,which indicates that the experiment result must be modified before it is analyzed. By analyzing the test result of mudstone in steady creep stage under cyclic temperatures,a new way to do the temperature corrections in a creep test was proposed,which can identify the thermal-strain rate and creep rate separately. The creep test result of mudstone under cyclic temperatures was adopted to verify and the thermal-strain rate of mudstone was calculated to be 2. 80×10^-5/℃ under a 25 MPa confining stress in room temperature range,and the modified creep test result of mudstone matched well with the Nishihara model. There is an obviously linear relationship between the steady creep rate and the axial deviatoric stress.