Abstract:In the Carboniferous-Permian coal seam in North China, the Huanghebei coalfield in Shandong is threatened by the water hazard from the roof-floor limestone aquifer, and the mining risk of the lower coal group is extremely high. In respect of such geological conditions, and as a result of analysis, summarization and exploration, a method of double-layer multi-branch drilling grouting to transform roof-floor limestone aquifers is proposed in this article, which enables the management of roof-floor limestone aquifers. This method innovatively adopts an open section common to roof and floor drill-holes, and is used to set different management targets according to the occurrence of rock formations, in addition to specific management methods. COMSOL Multiphysics is used for numerical simulation of the control parameters of the target rock formations, and reasonable grouting parameters and drilling spacing are determined in conjunction with control experience under similar conditions in China. After the application of this method, the safe mining of the lower coal group has been realized, and it has provided a reliable technological method and scientific guidance for the development of the more than 1 billion tons of coal resources threatened by water hazard in Huanghebei coalfield, as well as other similar mines and non-coal mines threatened by roof and floor water hazard. Meanwhile, this method has great application prospects.
