| Coal resources in Shanxi has made important contributions to China’s rapid economic sustainable growth. in the future for a long time, China’s energy structure will continue to maintain the overall pattern of coal as its main fuel.Coal mining activities intensified on the one hand to promote the rapid development of the local economy, on the other hand also to bring groundwater environment of Shanxi serious damage. Shanxi mineable coal seams mainly occur in the Carboniferous system the Taiyuan group and Permian Shanxi group, the interactions of coal-water formation, the caving cracks formed after the coal seam with the inevitable group in Taiyuan, Shanxi groupon the destruction of the overlying aquifer. Ordovician carbonate strata underlying the coal-bearing strata, if take reasonable mining methods and strict management measures, can avoid the karst aquifer destroyed, and the process of coal mining, karst groundwater pressure area of floor water inrush in karst aquifer is the greatest threat, so how to protect the Ordovician karst aquifer before us is a particularly serious problem. This paper takes Shanxi Fenxi Ruitai Zhengming mine as the research background, the deposit is located in the Niangziguan Spring Basin Runoff zone, there is pressure mining conditions, study the mining process has a very important practical significance influence on karst groundwater environment.The Zhengming mine in zuoquan County, area5.1558km, mining coal2、3、4、8、11、15、The Minable coal seam floor elevation in Ida, West were lower than those of Ordovician limestone karst water level elevation, mining will be threatened by Ordovician limestone karstic water in different degree, which belongs to the mining with pressure. Through the calculation of water inrush coefficient was found in2,3,4,8,11coal seam below have destroyed lots of critical water inrush coefficient0.06MPa/m, coal mining, generally will not affect the Ordovician Karst water. Therefore consider the No.15coal seam mining with pressure influence on karst water, the No.15coal seam under pressure conditions can be divided into four parts, namely, without pressure area, water inrush coefficient of0-0.06MPa/m,0.06-0.1MPa/m,0.1-0.138MPa/m area, this paper mainly consider0.060.1MPa/m regions were taken pre drainage measures impact on the groundwater environment.Based on hydrogeological condition in the study area of field investigation and test, analysis of dynamic characteristics of groundwater in the study, the generalization of karst aquifer medium system, established the Ming karst groundwater in coal mine are heterogeneous anisotropic three-dimensional conceptual model of unsteady flow.First application " big well method " finds lots of water inrush coefficient of0.06-0.1MPa/m reduced to0.06Mpa/m need to discharge water, and then apply the Visual MODFLOW software the predicted hydrophobic buck mining1a and2.7a after karstgroundwater level variation, the scientific evidence for the rational development and utilization of karst water of the study area and derive the following conclusions:1. Between Ida central water coefficient of water inrush is between0.060.1MPa/m site area of about1.1km2, the mining life of approximately1.7a, the distribution of F1, F2fracture, water inrush risk bigger, this simulation is mainly aimed at the site. Karst water level in the area originally830-845m, water inrush coefficient dropped to0.06Mpa/m, the water level is reduced by at least790-845m, arranged the two buck wells (J1, J2) prior to mining1a the water inrush coefficient is reduced to0.06Mpa/m, the hydrophobic volume per relief wells was calculated to be82.8m3/h. model of groundwater flow field, and the model is to identify and test more accurate fitting of the groundwater environment, predicted mine hydrophobic buck mining1a and2.7a of karst water level.3. la after the formation of precipitation funnel to J1, J2as the center, the water level drawdown funnel center is about40m, go on, downstream water level drawdown gradually become smaller, the maximum effect of upstream distance of about0.9km, the greatest impact downstream distance of about1.9km, the greatest impact crater on the left side of the distance of about1.5km, the greatest impact on the right side of the distance about1.1km, influence area is about13.8km2.4.2.7a water level drawdown funnel center is about64m, go on, downstream water level drawdown gradually become smaller, the maximum effect of upstream distance of about1.6km, the greatest impact downstream distance of about2.8km, the greatest impact crater on the left side of the distance of about2.3km, the greatest impact on the right side of the distance of about1.9km, influence area is about26.4km2. |
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