Abstract: The unit weight of model material in the physical simulation test on deep unloading formation mechanism of a slope is required to be equal to that of the prototype, and the strength is required to be 0.002 times that of the prototype. The model material is featured by relatively high unit weight and low strength. Developing and designing the required material is the key of the test. We conducted researches in terms of material selecting, mould designing, specimen manufacturing and mix ratio test, and finally obtained the composition, mix ratio and technique of the model material which meets the test requirements. The material is composed of iron powder, barite powder, quartz sand and rosin alcohol solution, which are mixed and compacted uniformly. The physical and mechanical parameters of the material could be adjusted in a large extent, and the content of components could also be adjusted for similar researches to get the corresponding parameters. This research is the technical assurance of the physical simulation test, and in addition, it provides experience for similar studies.

Key words: deep unloading, physical simulation, similar material, experimental research