Abstract:The stress relaxation tests of silty mudstone under triaxial compression are performed with the RLJW–2000 rock servo-controlled rheology testing machine. Based on the test results

the stationary Hooke-Kelvin model is first selected to describe the stress relaxation properties of silty mudstone. In accordance with the difference between the theoretical results of stationary model and the test results

it can be seen that large errors will be encountered without considering time-dependent behaviors of the parameters

so it is necessary to establish the non-stationary model of rocks. By constructing the relation between model parameters G2、H1 and the time

a three-dimensional non-stationary viscoelastic Hooke-kelvin model is established. Comparing the theoretical results of stationary and non-stationary models with the test results

it is shown that the non-stationary viscoelastic Hooke-kelvin model can more accurately reflect the stress relaxation properties of silty mudstone than the stationary model. The research can provide some references for the future study of the stress relaxation model of rocks.