临涣矿采煤沉陷区地下水与地表水水环境特征研究

发布时间：2018-04-30 20:01

本文选题：采煤沉陷区 + 地表水　；参考：《安徽大学》2017年硕士论文

【摘要】：煤炭在我国的能源消费结构中占有主导地位。目前,我国95%以上的煤炭开采方式为井工开采。煤炭开采过程中会造成强烈的地面扰动,导致地面沉降、地表沉陷等一系列问题,其中积水、坡地、裂缝是采煤沉陷地常见的三大特征。特别是淮北矿区,作为国家典型的资源枯竭型矿区,由于所处区域为淮河中游,具有高潜水位的地质条件,在煤炭开采过程中,必然引起地面沉陷。随着开采矿区的不断扩大,沉陷区也不断扩大,沉陷区常年积水使得两淮矿区形成了面积大小不等的各种湖泊湿地。沉陷区的形成必然导致地表水和地下水循环条件发生改变。因此,地表水和浅层地下水水文地球化学以及水环境质量评价的研究,对当地水资源可持续利用以及水环境保护具有重要意义。本文以淮北临涣矿采煤沉陷区地表水(包括浍河、香顺沟、沉陷区积水)和浅层地下水为研究对象,以丰水期、平水期、枯水期为时间变化特征,系统地研究两种不同水体常规水化学特征及其影响因素、氢氧稳定同位素特征、重金属含量特征以及对水环境质量进行评价。(1)临涣矿采煤沉陷区水化学特征表现为:地表水体TDS质量浓度较高,地表水丰水期、平水期、枯水期TDS平均质量浓度分别为:1170.6 mg/L、1301.5 mg/L和1562.9 mg/L,均表现为地下水的3倍左右;由Piper三线图和Gibbs图分析可知,该区地表水水化学类型表现为SO_4~(2-)Cl~--Na~+型,主要受蒸发作用影响,浅层地下水水化学类型表现为HCO_3~--Ca~(2+)-Mg~(2+)型,受岩石风化和蒸发作用双重影响,岩石风化为主要作用;Piper三线图和因子分析结果显示,地表水和浅层地下水相互补给较弱,二者主要离子来源主要为水岩相互作用产生的溶蚀作用,体现出受大气降水补给的特点。地表水离子组成受蒸发作用、地表径流以及采煤活动等因素影响,浅层地下水体现出水体易溶盐的特点。(2)氢氧稳定同位素特征研究表明:地表水和浅层地下水具有相同水源特征,二者均来自于大气降水,但浅层地下水更多的来自于大气降水的直接入渗,而非地表水补给;与深层地下水氢氧稳定同位素对比可知,沉陷区地表水和浅层地下水并未受到深层地下水的混合;通过两端元法计算可知,浍河河水对周边地下水的补给带在距离河岸500m附近。(3)对临涣矿采煤沉陷区地表水使用综合水质标识指数法,对浅层地下水使用内梅罗指数法进行环境质量评价,结果可知:沉陷区地表水水质一般,总体达到Ⅲ类水水质标准,CODCr、TN、F~-、Cr超出地表水Ⅳ类水质标准,超标较为严重;浅层地下水超出地下水Ⅲ类水标准,F~-、NH4~+-N、Cr、Ni超标严重;对比传统和改进内梅罗指数法可知,改进内梅罗指数法考虑了地下水质量评价中评价因子的权重因素,在评价过程中纳入权重值最大的评价指标,使其结果更为客观。(4)临涣矿采煤沉陷区重金属含量时空变化规律及风险评估研究结果表明,该地区地表水和浅层地下水中Cr含量超标严重,存在污染风险。综合研究发现,地表水重金属含量较浅层地下水偏低,是由于地表水接受浍河河水和大气降水补给,更新速度快,而地下水所处封闭环境导致地下水重金属含量偏高,与地表水水力联系较弱。
[Abstract]:Coal occupies a dominant position in the energy consumption structure of our country. At present, more than 95% of China's coal mining method is well mining. In the process of coal mining, there will be a strong ground disturbance, which leads to a series of problems such as ground settlement and surface subsidence, of which water accumulation, slope land and crack are the three common characteristics of coal mining subsidence. As a typical resource exhausted mining area of the country, the northern mine area is a geological condition with high submersible water level in the middle reaches of Huaihe. In the process of coal mining, it is bound to cause ground subsidence. With the continuous expansion of mining area, the subsidence area is expanding, and the annual water accumulation in the subsidence area has made the area of two Huaihe mining areas to be different in size and size. The formation of all kinds of lake wetlands. The formation of subsidence area inevitably leads to the change of surface water and groundwater circulation conditions. Therefore, the study of the hydrogeochemical and water environmental quality evaluation of surface water and shallow groundwater is of great significance for the sustainable utilization of local water resources and the protection of water environment. This paper is based on the mining subsidence area of Huaibei Lin Huan mine. The surface water (including the river, Xiang Shun gully, the accumulated water in the subsidence area) and the shallow groundwater are the research objects. The characteristics of the conventional hydrochemical characteristics and the influencing factors of the two different water bodies, the characteristics of the hydrogen and oxygen stable isotopes, the characteristics of the heavy metals and the quality of the water environment are evaluated. (1) The hydrochemical characteristics of the coal mining subsidence area are as follows: the TDS mass concentration in the surface water body is high, the average mass concentration of TDS in the surface water and the dry water period is 1170.6 mg/L, 1301.5 mg/L and 1562.9 mg/L respectively, all of which are about 3 times of the groundwater; the surface water and water chemical types of the area are shown by the Piper three line map and the Gibbs diagram analysis. For SO_4~ (2-) Cl~--Na~+ type, mainly influenced by evaporation, the hydrochemical type of shallow groundwater is characterized by HCO_3~--Ca~ (2+) -Mg~ (2+) type, which is influenced by rock weathering and evaporation, and rock weathering is the main function. The result of Piper three line diagram and factor analysis shows that the surface water and the shallow groundwater facies are complementary to the other, and the two main ions are the main ions. The source mainly consists of the dissolution of water rock interaction, which embodies the characteristics of the recharge of atmospheric precipitation. The surface water ion composition is influenced by evaporation, surface runoff and coal mining activities. The shallow groundwater reflects the characteristics of soluble salt in water body. (2) the characteristics of hydrogen and oxygen stable isotopes show that surface water and shallow underground water are used. With the characteristics of the same water source, all of the two are derived from the atmospheric precipitation, but the shallow groundwater is more derived from the direct infiltration of the atmospheric precipitation, not the surface water supply, and the surface water and shallow groundwater in the subsidence area are not mixed with the deep groundwater. The recharge of the river water to the surrounding ground water is near the riverbank 500m. (3) the comprehensive water quality identification index method is used for the surface water of the coal mining subsidence area of the coal mining subsidence area. The Nemero index method is used to evaluate the environmental quality of the shallow groundwater. The result shows that the surface water quality of the subsidence area is the same, and the water quality standard of class III is generally reached, CODCr, TN, F~-, Cr. Beyond the standard of surface water type IV water quality, exceeding standard is more serious; shallow groundwater is beyond the type III water standard of groundwater, F~-, NH4~+-N, Cr, Ni exceed the standard. Compared with the traditional and improved Nemero index method, the improved Nemero index method considers the weight factor of the evaluation factor in the evaluation of groundwater quality, and the maximum weight value is included in the evaluation process. (4) the study on the temporal and spatial variation of heavy metal content in the mining subsidence area of the coal mining subsidence area and the study on the risk assessment show that the Cr content in surface water and shallow groundwater in this area is too serious and has the risk of pollution. The comprehensive study shows that the heavy metal content of surface water is lower than that of shallow groundwater, because the surface water is low. Water is recharged by water and atmospheric precipitation, and the rate of renewal is fast, and the closed environment of groundwater leads to the high heavy metal content in groundwater and weak hydraulic contact with the surface water.

【学位授予单位】：安徽大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X752;X143

【相似文献】