Abstract: At present, there are few similar materials that can reasonably simulate the rheological behavior of soft rock. It is also still in the exploratory stage to study the long-term rheological behavior of soft rock engineering based on the model test method. In this paper, a new rheological similar material of soft rock was developed, which compose of the iron powder, barite powder and quartz sand as aggregate, the rosin alcohol solution as binder and the hydraulic oil as viscous agent. This material processes a low strength and a significantly rheological property, which can not only simulate the transient elastoplastic properties of soft rock, but also simulate the rheological properties well. With a constant aggregate proportion, a series of gradient compounding tests were conducted by adjusting the concentration of rosin alcohol solution m and the content of hydraulic oil w. The tests results indicate that the main parameters associated with the instantaneous strength and deformation of the similar material as well as the rheological parameters of Nishihara model are all affected by the factors m and w. The higher the concentration of the rosin solution, the larger the strength and the smaller the rheology of samples are. A higher hydraulic oil content leads to lower strength and more obvious rheological behavior. Compared with the concentration of the rosin alcohol solution m, the hydraulic oil content w exerts more remarkable influence on the parameters of Nishihara model. Finally, the developed similar material was applied to the model test of the shield inclined shaft in the weak sandy mudstone in Shenhua Xinjie coal mine. The model test results show that, the instantaneous mechanical properties and rheological properties of the material meet the test requirements, which provides guarantee for good results.

Key words: soft rock, rheology, similar material, viscoelastic plasticity, Nishihara model, model test