Abstract: In this paper, to reveal the water change process of water-inrush aroused by fault activation, based on the example analysis of water inrush through fault in the fully mechanized top-coal caving face, the similar material simulation models of water inrush aroused by fault activation under different water pressures were designed, including the coal mining under the hanging wall and foot wall of fault, respectively. Meanwhile, the variation rules of Reynolds numbers, fillings and voidage of fault zone along with time were analyzed according to the test data, and the variation rules of voidage and water inflow along with time were comparized. The results show that the water inrush aroused by fault activation in fully mechanized top-coal caving has experienced the process of pore fluid, fracture flow and pipe flow, and the time when the pore fluid converses into fracture flow（7，9，13 and 15 s）is identified according to the variation law of filling emission quantity along with time, while the time when the fracture flow converses into pipe flow（30，35 and 40 s）is obtained according to the change law of voidage along with time. The test results have explained the conversion phenomenon from seepage to flow of water inrush aroused by fault activation in fully mechanized top-coal caving, and are anastomotic with the expressive characteristics of field examples.

Key words: fully mechanized top-coal caving, fault activation, water inrush, conversion from seepage to flow, similar material simulation