Research On Slurry Diffusion Law Of Horizontal Grouting Hole In Ordovician Karst Fissure Aquifer

The level below-980 of Xingdong Mine is deep mining area,there have been three times of Ordovician water inrush after the mine has entered this area,and the risk of water inrush from the deep Ordovician limestone is obviously increased.In order to better prevent and control water inrush from the Ordovician limestone and to protect the Ordovician Water Resources as far as possible,the mine uses the technology of "surface oriented near horizontal bedding branch drilling group" to carry out the regional advanced exploration and governance of the Ordovician aquifer specific horizon.There is still a lack of research on the law of serous diffusion in the vertical fissure of deep stratum with deep high confining pressure and high hydrostatic pressure.The paper relies on Shanxi Provincial Coal Mine Prevention and Control Technology Key Laboratory Project to carry out relevant research,which has important theoretical and practical significance.Based on the analysis of relevant documents,the hydrogeological conditions of Xingdong Mine and the basic characteristics of Ordovician karst fissure aquifer are studied,combining "The Xingdong Mine regional exploration governance project below-980 level " and selecting grouting quality,the loss of drilling fluid,average water absorption,length of grouting section,water level in Ordovician limestone,difference in water level before and after pumping,and distance between the horizontal hole and the top interface of Ordovician limestone,the grey correlation analysis method was used to determine the main factors affecting the grouting quantity.Then,analytic hierarchy process was used to establish an evaluation system for grouting quality influencing factors and calculate the weight of each main control factor in the whole grouting quantity influence factor evaluation system.It is concluded that the main factors relating to the grouting quantity are the loss of drilling fluid,average water absorption and the length of grouting section.The parameters of rock mechanics parameters in the eighth section of Ordovician limestone and the viscosity of cement grout in different water-cement ratios are used as model parameters for numerical simulation.The UCD discrete element software was used to establish a model of horizontal dispersion of slurry in the grouting hole.The effects characteristics of grouting pressure,crack width and water-cement ratio on the diffusion range of the slurry were simulated.The empirical formulas of fracture width,water-cement ratio,grouting pressure and slurry diffusion range were obtained.A single fracture model and a serosity model with orthogonal faults have been established,and the pressure variation characteristics curve of a single fracture and an orthogonal fault zone have been obtained.The change curve of the sharp rising pressure grouting pressure and the change curve of the slowly rising grouting pressure in "The Xingdong Mine regional exploration governance project below-980 level " are in agreement with the characteristics of the pressure change curve in numerical simulation,indicating that the numerical simulation results are in line with the actual situation.