<p>The damage mechanism of the coal seam floor is critical for water inrush prevention. As a novel mining method, the non-pillar mining with the automatically formed roadway (NMAFR) technique has shown potential in reducing floor damage and mitigating water inrush risks. To investigate the mechanisms of floor damage reduction and water inrush prevention in the NMAFR, a model test system for mining above confined was developed. Using the 11,004 working face of Rongkang Coal Mine as background, two comparative physical model tests were conducted. The Test I focused on analyzing the influence of mechanical, time, and spatial factors in the roof-cutting effect. The Test II compared the strain concentration factor and shear states of the floor under conditions with and without coal pillars, confirming the positive role of the non-pillar effect in reducing floor damage. After the tests, the equilibrium state of the surrounding rock structure in the gob was evaluated based on the fractal dimension of the fracture network, further demonstrating the importance of the equilibrium effect in minimizing floor damage. Finally, to assess the comprehensive action of multiple effects in water inrush prevention, the lifting height, flow rate and cumulative volume were used as evaluation indicators to study lifting difference of confined water. The results verified that the roof-cutting effect, non-pillar effect, and equilibrium effect of the NMAFR can effectively reduce floor disturbance and damage degree, significantly lowering the risk of water inrush.</p>