Research On The Hydrogeological Structure Of Thick Loose Formation And Water Gushing Settlement In Liliangdian Mine

The coalfields which distributed in eastern China, especially in Huanghuai Plain and Sanjiang Plain, are covered by large thick loose aquifer. Due to the complex hydrological and engineering geological conditions,it is more probably for water inrush and sand crushing when coal seam under large thick loose formation is mined. Meanwhile, the former exiting water and sediment dynamic equilibrium conditions will be broken for mining induced water inrush of the Cenozoic loose aquifer, resulting in ground settlement for water gushing.Liliangdian coalmine is a typical large thick loose formation mining area which average thickness of Cenozoic loose formation is 523.6m. Therefore, the hydrogeological structure and water-rich rule research of the large thick loose formation has a great importance to guarantee the safety of shallow mining area in coalmine. In addition, the Shijiangzhuang-Wuhan high-speed railway, the Beijing-Guangzhou railway and other important buildings pass through the coalfield, the volume and range of the mining subsidence and gushing subsidence in the coalfield have to be predicted, to ensure safe operation of the railway.Based on one by one analysis and statistics of data revealed by the exploration drilling, "five segments" hydrogeological structure of Cenozoic in Liliangdian coalmine were proposed, of which segments â… and â…¢ are primarily water-rich segments, segment â…¡ and segment â…£ are aquifuges, and the bottom segment â…¤, composed of interbedded sand and clay, has a direct impact on the coal mining. On this basis, the Cenozoic waterproof and sand prevention coal pillar range were delimited. Take 12011 first mining face as the research object, water inflow of bottom Cenozoic aquifer was calculated, which is 18.6 m3/h, and the numerical simulation was used to predict the flow field evolution of the bottom Cenozoic aquifer after water gushing. The results showed that the maximum water level drawdown of Shijiangzhuang-Wuhan high-speed railway is 32 m, the maximum water level drawdown near the Beijing-Guangzhou railway eventually stabilizes at 3m. On this basis, the gushing subsidence mechanism of the first mining area was focused on, a gushing subsidence computational model was established, and water inflow of the Shijiangzhuang-Wuhan high-speed railway and the Beijing-Guangzhou railway was calculated. The results show that final settlement will reach 9.28 mm in Shi-Wu high-speed railway and 0.87 mm in Beijing-Guangzhou railway. Based on the above, synthetically considering the mining subsidence and gushing subsidence range, the original protection coal pillar has expanded nearly 150 m and the forbidden mining area of the coalfield was divided.