To analyse the impact of underground pressure on the variation in floor porosity and pore water pressure distribution during the coal seam mining process, this paper uses closed and open water pressure sensors to analyse rock pressure, water pressure zoning and layer distribution characteristics of the coal seam floor under mining effects based on a simulation analysis method using similar rock materials; the results determine that the separation characteristics of the pore water pressure distribution are affected by the rock pressure ‘barrier’ function, which is caused by changes in rock permeability under the coupling effect. To quantitatively analyse the rock pressure barrier’s impact on the floor mechanical structure, this paper proposes the ‘virtual separation layer’ concept and defines the virtual separation layer index to determine the scope of the floor tension fracture zone. Through monitored data of pore water pressure at different depths of the floor during field mining, the variation between the water pressure, porosity, mining distance and floor depth is obtained; similar material simulation results are verified, and a zonal distribution model of pore water pressure in the floor is established, providing a reference to investigate the distribution of pore water pressure in the floor under mining disturbances. The results show that the influence of changes in mining stress will also lead to a differential distribution of the floor mechanical properties and ultimately damage the floor and affect the inrush of the confined water. The research results play an important role in risk classification and prevention of water pressure distribution in coal seam floors.

为了分析煤层开采过程中地下压力对地层孔隙度和孔隙水压力分布变化的影响，本文采用封闭和开放水压传感器分析了煤层的岩压，水压分区和层分布特征。基于相似岩石材料的模拟分析方法，对开采作用下的底板进行了模拟；结果表明，孔隙水压力分布的分离特征受岩石压力“屏障”函数的影响，该函数是在耦合作用下岩石渗透率的变化引起的。为了定量分析岩石压力屏障对地板机械结构的影响，本文提出了“虚拟隔离层”的概念，并定义了虚拟隔离层的指标来确定地板张力断裂带的范围。通过现场开采过程中不同深度的地表孔隙水压力监测数据，得出水压，孔隙度，开采距离和地层深度之间的变化。验证了相似的材料模拟结果，建立了底板孔隙水压力的区域分布模型，为研究开采扰动下底板孔隙水压力的分布提供了参考。结果表明，采矿应力变化的影响也将导致底板力学性能的差异分布，并最终损坏底板并影响承压水的涌入。