采空区覆岩垮落及孔隙率演化规律研究

Research on the Evolution Law of Overburden Rock Collapse and Porosity in Goaf

为研究深部煤层采空区上覆岩层裂隙场演化规律,针对新河煤矿7312工作面的实际地质条件,采用经验公式的方法确定各岩层的细观力学参数,利用PFC3D数值模拟软件建立上覆岩层颗粒流模型,得到了综放采空区覆岩垮落和孔隙率的变化。结果表明:从回采距离30 m开始,上覆岩层开始垮落;工作面全部回采完毕后,孔隙率基本稳定在0.42左右。

In order to study the evolution law of the fracture field of the overburden rock in the goaf of deep coal seams,in view of the actual geological conditions of the 7312 working face of Xinhe Coal Mine,the empirical formula method is used to determine the mesomechanical parameters of each rock stratum,and the PFC3D numerical simulation software is used to establish the grain flow model of the overburden rock,and the changes of the overburden rock collapse and porosity in the fully mechanized top coal caving goaf are obtained.The results indicate that starting from a mining distance of 30 m,the overburden rock begins to collapse;After all the mining of the working face is completed,the porosity is basically stable at around 0.42.