Seepage Field-Strain Field Coupling Analysis for Rock Masses of Coal Seam Floor during Mining Based on COMSOL

Based on the fluid-solid coupling theory, The fractured rock mass was described as a continuous porous medium, and consider the rock mass permeability coefficient has a relationship with the stress and strain. The dynamic change of permeability coefficient was achieved using the multi-physics coupling analysis software COMSOL, and found that the stress and strain of surrounding rocks changes a lot due to mining. The maximum stress and strain in the mudstone area reaches 2-3 times of the original one, which happened at the immediate roof of mined-out area. According to the analysis of seepage field, mining does not destroy water resistance of floor aquifer. Mining fissures do not connect limestone aquifers, and water in the limestone is less likely to flow into stop to cause damage.