Model and selection criterion of zonal preact grouting to prevent mine water disasters of coal floor limestone aquifer in North China type coalfield

In order to promote the development of zonal preact grouting technology and establish a system of the technology to prevent mine water disasters of coal floor aquifer, the authors analyze and summarize the coal seam occurrence and hydrogeological conditions of the Carboniferous-Permian coalfields in China, starting from the engineering systematicity, focusing on the three main factors of drilling conditions, grouting layer selection and drilling technology in the engineering of zonal preact grouting to prevent mine water disasters of coal floor aquifer. The model of zonal preact grouting to prevent mine water disasters of coal floor aquifer is established, which can be applied in the geological and hydrogeological conditions of the North China type coalfields. Combined with the identification of coal seam depth, water pressure on coal seam floor and structural combination of floor rock formation, the selection criteria of various governance modes are determined; Further combined with the two additional indicators of drilling pattern and grouting material, the sub-class model of advanced zonal governance is further divided. Taking the practice of three major zonal preact grouting projects in the Huaibei mining area and the Hancheng mining area as examples, the selection principle and engineering application effects are analyzed. The results show that the model classification method can cover all zonal preact grouting engineering in China. The research provides guidance for the selection of the zonal preact grouting engineering model of coal seam floor aquifer and the implementation of the grouting project.