Floor precise grouting for prevention and control of water based on confined water single-hole drainage experiment

The North China type coalfields are generally threatened by the floor confined water,and the grouting trans-formation of floor is an effective way to prevent and control the confined water disaster. However,most of the grouting transformation layers are heterogeneous limestone,and the grouting conditions are difficult to ascertain,so the efficien-cy of grouting is limited. In order to improve the effect of prevention and control of floor water hazards,the floor precise grouting based on confined water single-hole drainage experiment had been studied. The Weibei Coalfield,especially Dongjiahe Coal Mine in Chenghe Mining Area was taken as the research background. Based on the analysis of the characteristics of floor water hazard prevention and control in the study area,and combined with the connotation of floor precise grouting,a single-hole drainage experimental device and its supporting application technology had been developed. On the basis of single hole drainage experiment,combined with dominant surface water inrush theory,the floor classification grouting technology had been proposed. The results show that the single-hole discharge experiment can be realized by setting a constant flow control valve,and the permeability coefficient K and water enrichment coeffi-cient q of confined water can be obtained. Combined with the design of circumferential incomplete wells,the main run-off direction in the horizontal direction of confined water can be obtained. According to the hydrological parameters ob-tained from the single-hole discharge experiment and based on the dominant surface theory of water inrush,grouting conditions can be divided into five categories and seven sub-categories, including non-water-rich type, Q-S curve straight line type I,Q-S curve straight line type II,Q-S curve parabola type I,Q-S curve parabola type II,Q-S curve power function type,and Q-S curve logarithmic type. According to the importance of different grouting conditions,each type of grouting technology was proposed. The application in engineering practice shows that the grouting project using classified grouting technology improves the efficiency and effectively controls the floor water hazard. The research re-sults provide new technology and equipment for the prevention and control of confined water hazards in the floor of North China Coalfield.