Solving hydrogeological parameters of thick sandstone based on various analytical and numerical methods

Abstract

In the process of coal mining, accidents such as water inrush in mines can not only cause huge economic losses, but also seriously threaten the safety of workers. Hydrogeological parameters play an important role in calculating the amount of water inflow in mines. Therefore, accurately measuring the hydrogeological parameters of aquifers is of great significance for coal mine water prevention and control work. In order to obtain more practical hydrogeological parameters of the thick sandstone aquifer in the Luohe Formation of the mining area roof, based on the pumping test data of the upper and lower sections of the Luohe Formation sandstone aquifer in Xinzhuang Coal Mine, traditional analytical methods such as Theis formula method, Jacob line diagram method, and water level restoration method for unstable flow were used, and combined with the actual site characteristics, the upper and lower sections of the Luohe Formation sandstone aquifer were calculated The permeability coefficients of the lower section are 0.22～0.59 and 0.03～0.35 m/d respectively; The upper section has a hydraulic conductivity coefficient of 128.74-373.67 m2/d, while the lower section has a conductivity coefficient of 5.52-47.07 m2/d; The water storage coefficient of the upper section is 2.22×10−4-6.69×10−3, the lower paragraph is 6.53× 10−5-3.29×10−3. And a numerical model of groundwater flow in the Xinzhuang mining area was established using FEFLOW software to solve the hydrogeological parameters of the Luohe Formation aquifer. The permeability coefficients of the upper and lower sections of the Luohe Formation were obtained to be 0.55 and 0.45m/d, respectively. By comparing and analyzing various methods, it is shown that the hydrogeological parameters obtained through numerical simulation are similar to the results calculated by various analytical methods. On this basis, the mine water inflow was calculated based on the hydrogeological parameters obtained by various methods, and compared with the actual water inflow. The results showed that in the upper section of the aquifer, the hydrogeological parameters calculated using numerical simulation method were closer to the actual water inflow; In the lower section of the Luohe Formation, the hydrogeological parameters calculated using Jacob's line diagram method are closer to the actual water inflow. This further improves the accuracy of hydrogeological parameter calculation, providing a basis for later research on aquifer water abundance, prediction of mine water inflow, and mine water prevention and control work in similar mining areas with thick sandstone aquifers in the Luohe Formation.

Keywords

• mine water inflow (inrush)
• hydrogeological parameters
• pumping test
• luohe formation sandstone