Optimization technology for group hole drainage of coal mining above deep high pressure and low permeability limestone aquifer
Abstract Drainage for decreasing water pressure is one of the effective measures to prevent and control water disaster caused of coal mining above high pressure limestone aquifer. The deep limestone aquifer in Huaibei mining area generally has the characteristics of high water pressure, low permeability and uneven water abundance so it is generally difficult to meet the requirements for single-hole drainage. In order to achieve the best drainage effect and consider the requirements of engineering quantity and environmental protection, a multi-objective group hole drainage optimization model was established, which takes the minimum of single-hole flow rate and hole number as the objective function and the requirements of drainage borehole and water level control point drawdown as the constraint conditions. And the particle swarm optimization algorithm was used to solve the model. On this basis, the influence of permeability coefficient and water storage coefficient on the calculation results was discussed. The results show that the permeability coefficient and water storage coefficient have great influence on the optimization of single-hole flow rate and the number of holes. For the low permeability aquifer, measures such as using partially penetrated well, appropriately increasing the number of drainage boreholes and reducing the single-hole flow rate have good drainage effect. And the drilling work amount and total drainage amount are relatively small. These are all good layout schemes for drainage. According to the results of optimization, the drainage of a coal face in Huaibei was guided and achieved good results.