Abstract: North China mining area is affected by limestone water of Taiyuan formation and Ordovician at the bottom of the Permian coal series permo carboniferous coal. In order to analyze the load-transfer characteristics and failure mechanism of the water-resisting floor in response to the dual function of mine-induced stress and water pressure, confined water automatic loading system has been designed, and the failure process of the floor aquifuge fracture initiation, expansion and transfixion has been showed through physical simulation during re-mining. Thus, fracture distribution characteristics and formation mechanism have been presented at the different layers of floor, and through the displacement measurement system, the deformation rules and district characteristics have been drawn.

Key words: re-mining, water-resisting floor, physical simulation, fracture evolution, mechanical mechanism