Advanced drainage technology based on multi objective constraint of mine safety and water resources protection

Advanced drainage is one of the main means of roof water disaster control in Jurassic coalfield in western China. However，lack of water resources leads to ecological fragility. Therefore，how to minimize the impact of advanced drainage on the groundwater ecological environment is an urgent problem to be solved while reducing water inflow in coal mines to ensure safe production. In this paper，the response function matrix of groundwater system variation characteristics is determined by establishing the groundwater mathematical simulation model of the non structural grid in the mining area. Based on this，the groundwater management model under the multi objective constraints of mine safety，water resources protection and efficient drainage is constructed. Through the linear objective programming calculation，the optimization scheme of advanced drainage of mine water is determined，including the location distribution of drainage boreholes，the drainage volume and time management in the drainage process. Taking the Caojiatan Coal Mine in Shaanxi Province as an example，the calculation results show that compared with the traditional equidistant drainage scheme，the time relationship of the Quaternary aquifer receiving rainfall recharge is considered in the optimized advanced scheme. The influence on the Quaternary phreatic water is also significantly reduced while reducing the drainage volume. In the case of a 50% reduction in the number of drainage boreholes and a 42.60% reduction in the total drainage volume，the average reduction in water inflow is basically the same，while the overflow increase from the Quaternary aquifer is significantly reduced by 50.09%. This paper not only systematically studies the influence of advanced drainage drawdown on the interaction between Quaternary loose pore aquifer and bedrock fissure aquifer，but also evaluates the critical value of water control drawdown in the study area.