Abstract:To study the variation of hydraulic parameters of unsaturated zone in the coal mining subsidence cracks region, the soil particle size distribution, soil water characteristic curves (SWCCs) and unsaturated hydraulic conductivity curves (UHCCs) were measured and analyzed in PanJi coal mining subsidence area in Huainan compared with the no-Subslihen cearea. The results showed that the hydraulic parameters of unsaturated zone chagend continuously in the coal mining subsidence in steady phase, and subsidence fissures had reduced the slope of the SWCCs and the SWCCs air entry value, and then resulted in higher water-holding capacity. Under the same matrix potential, the UHCCs of subsidence area soil significantly is lower than that of the non-subsidence area. This was due to the precedence flow in subsidence fissure, which would produce non-water-conductive fissure zone and resulted in the decrease of moisture content and hydraulic conductivity. All the results above will provide significant basis for experimental studies in water movement process of unsaturated zone in coal mining subsidence region.