Abstract: To reveal the movement characteristics of rock and soil mass due to underground mining under thick unconsolidated layers, which are different from those of normal condition mining, the simulated material model test was employed to simulate the rock and soil mass movement laws in this paper, and the model test data were then compared with field subsidence monitoring measurement. Thus, the mining-induced movement laws of rock and soil mass in mining areas with thick unconsolidated layers are obtained, and the particularity of subsidence laws for loose soil mass is pointed out, when compared with the laws of normal condition mining. Through the comparison with the subsidence values and mining degree of rock and soil mass, the controlling role of bedrock on surface subsidence is shown, then the difference of movement basins in bedrock surface and ground surface is described, and the movement mechanism of rock and soil mass is finally revealed. The results can provide reference for subsidence prediction, object prevention, safety and high efficiency mining in thick unconsolidated mining area.

Key words: thick unconsolidated layers, mining subsidence, two-layered medium, model test