采煤对榆溪河流域地下水资源的影响研究

Study on the influence of Coal Mining on Groundwater Resources in Yuxi River Basin

榆溪河位于榆阳区境内,全长98 km,流域面积近4 000 km2,根据地形地貌及支流分水岭等整个流域被划分为10个水源地。本文依据流域水文地质条件构建水文地质概念模型,在此基础上基于可视化数值模拟软件(Processing Modflow)建立流域三维地下水流数值模型,模型经识别与校验完成后,加载煤矿矿坑涌水工况,模拟煤矿开采对地下水资源的影响,预测未来30年末的地下水末流场、末埋深场、末降深场、潜水位降深曲线以及地下水补排均衡量,并进行分析评价,得出主要结论为:(1)在地下水及煤矿现状开采条件下,未来30年末水源地地下水处于负均衡状态,负均衡主要为消耗深层侏罗系地下水资源储存量。(2)煤矿开采涌水主要对矿井及其周围的潜水位产生一定的影响,金鸡滩镇附近由于煤矿矿坑疏干地下水会形成一个较大的降落漏斗区域,潜水位最大净降深约3m,影响半径约15 km。(3)流域地下水位呈缓慢平顺的发展态势,没有出现地下水位急剧变化的情况,未来30年地下水位下降一般0.5~2.3 m,煤矿附近最大地下水位下降约3 m。研究成果可为榆溪河流域煤矿开采和水资源利用规划提供依据。

Yuxi River is located in the territory of Yuyang District,with a total length of 98 km and a drainage area of nearly 4000 square kilometer.According to topography and watershed,the whole river basin is divided into 10 water sources.Based on hydrogeological conditions in hydrogeology,this paper constructs a conceptual model of hydrogeology.On this basis,we establish a 3 D numerical model of groundwater flow based on Processing Modflow.After the model is identified and verified,the gushing conditions of coal mine pit are simulated.Coal mining on groundwater resources,predicting the groundwater terminal flow field,the end buried depth field,the final falling depth field,the diving potential depth curve and the groundwater recharge balance at the end of the next 30 years are analyzed and evaluated.The main conclusions are as follows：：（1）Groundwater and coal mine status quo mining conditions,the next 30 years groundwater in the water source is in a negative balance,negative balance mainly for consumption of deep Jurassic groundwater resources storage.（2）The gushing water from coal mining mainly affects the mine and the surrounding diving potential.As the dredging groundwater near the coal mine pit forms a larger landing funnel area,the maximum net depth of the diving water is about 3 m,affecting Radius of about 15 km.（3）The groundwater table in the basin showed a trend of slow and smooth development.There was no drastic change in the groundwater table.The groundwater table dropped by 0.5 ~ 2.3 m in the next 30 years and the maximum groundwater table dropped by about 3 m in the vicinity of the coal mine.The research results can provide the basis for the coal mining and water resources utilization planning in Elxi River Basin.