Abstract: The stability of underground projects like roadway tunnel is greatly affected by the rheology of surrounding rock. A correct understanding of the rheological properties of rock is beneficial to the design, construction and operation of geotechnical engineering. The axial rheology regularity of mudstone sample collected from Zhuji coal mine was researched as an example. Uniaxial visco-elasto-plasticity rheological tests were carried out by step loading, and the Origin software was employed to analyse the test data in depth. Furthermore, the axial rheology curves were fitted using Burgers model and the seven-component nonlinear visco-elasto-plastic rheological model, also known as Hohai model, to determine the mechanical parameters of rheological models. Comparison between the fitting curves and the test curve shows that two rheological models could both reflect the creep process at low stress level; but the Hohai model could reflect the three rheological stages more accurately whereas the Burgers model has large deviations when the stress approaches the long-term strength.

Key words: mudstone, rheological test, axial rheology, rheological model, stress level