厚黄土覆盖区煤矿开采对不同水力条件松散含水层影响的数值模拟研究

发布时间：2018-04-28 23:14

本文选题：厚黄土地区 + 煤矿开采　；参考：《太原理工大学》2017年硕士论文

【摘要】：我国煤炭资源丰富,煤炭作为主体能源,对经济社会发展具有重要作用,同时煤矿开采也对地下水环境带来的不可恢复的破坏。在我国西北地区,煤矿往往存在于较厚的黄土层下,而厚黄土层中的松散含水层则是当地居民的主要用水水源,由于近年来煤矿的大量开采,导致煤矿上覆地层结构发生改变,形成冒落裂隙带,使得煤层上覆含水层地下水沿此通道快速流失,或加大松散含水层地下水向下伏含水层的越流补给量,直接影响居民生活用水,间接破坏该地区地下水平衡。针对厚黄土地区煤矿开采对第四系松散含水层破坏的这一问题,本文以山西省长治市屯留县境内常村煤矿为研究背景,在调查、收集、分析该地区地质、水文地质资料的基础上,构建水文地质概念模型,数学模型,运用基于有限差分法的GMS地下水数值模型模拟的计算机软件对模型进行模拟求解。通过改变松散含水层基础水力条件,定量研究S6采区开采结束后,导水裂隙带未沟通松散含水层、弱透水含水层性质不变条件下,采煤对不同水力特征的第四系松散含水层的影响。根据模拟结果,得到主要结论如下:(1)煤矿开采前,研究区内松散含水层地下水处于自然状态下的动态平衡,当煤矿开采结束后,冒落裂隙带形成,加大松散含水层地下水通过导水裂隙带向下的越流补给量,以致采区范围出现水位大幅度下降情况,产生降落漏斗,漏斗影响范围及最大水位降深随时间的增加而增大,并在预测前期变化较大,后期变化较小。(2)不同渗透系数情况下,保证冒落裂隙带距弱透水层底板距离不变,弱透水层厚度及渗透系数等条件不变,以研究采煤对不同渗透系数松散含水层的影响。模拟结果显示,不同渗透系数下,降落漏斗的影响面积、漏斗中心最大水位降深不同,预测前期渗透系数大者,降深大,影响面积大,预测后期,渗透系数大者降深小,影响面积大,最大影响面积为73.00km~2,最大降深为13.60m。(3)不同水头情况下,保证冒落裂隙带距弱透水层底板距离不变,弱透水层厚度及渗透系数等条件不变,以研究采煤对不同水头松散含水层的影响,模拟结果显示,不同水头条件下,降落漏斗的影响面积、漏斗中心最大水位降深不同,整个预测期内,水头大者,影响面积及最大水位降深大,最大影响面积达74.90km~2,最大水位降深达18.81m。
[Abstract]:China is rich in coal resources. Coal, as the main energy source, plays an important role in the development of economy and society. At the same time, coal mining also brings irreparable damage to the groundwater environment. In northwest China, coal mines often exist under the thick loess layer, and the loose aquifer in the thick loess layer is the main water source for the local residents. Because of the large amount of coal mining in recent years, the overlying stratum structure of the coal mine has been changed. The formation of caving fissure zone causes the rapid loss of groundwater in the overlying aquifer along this channel, or increases the overflowing recharge of the groundwater in the loose aquifer, which directly affects the domestic water consumption and indirectly destroys the groundwater balance in this area. In view of the problem that coal mining in thick loess area destroys the Quaternary loose aquifer, this paper takes Changcun Coal Mine in Tunliu County, Changzhi City, Shanxi Province as the research background, investigates, collects and analyzes the geology of this area. On the basis of hydrogeological data, a hydrogeological conceptual model and a mathematical model are constructed, and the model is simulated and solved by computer software of GMS groundwater numerical model based on finite difference method. By changing the hydraulic conditions of the foundation of the loose aquifer, the quantitative study is made on the condition that, after the exploitation of the S6 mining area, there is no communication between the loose aquifer and the weakly permeable aquifer in the fissure zone. The influence of coal mining on Quaternary loose aquifer with different hydraulic characteristics. According to the simulation results, the main conclusions are as follows: before the coal mining, the groundwater of the loose aquifer in the study area is in the dynamic equilibrium under the natural state, and when the coal mining is finished, the caving fissure zone is formed. Increasing the amount of overflowing recharge of the loose aquifer groundwater through the water diversion fissure zone, resulting in a large drop in the water level in the mining area, resulting in a drop funnel, the influence range of the funnel and the maximum depth of the water level drop increasing with the increase of time. In the case of different permeability coefficients, the distance between the caving fracture zone and the weak permeable layer bottom plate is not changed, the thickness of the weak permeable layer and the permeability coefficient are not changed. In order to study the influence of coal mining on the loose aquifer with different permeability coefficient. The simulation results show that the influence area of the drop funnel and the maximum water level in the center of the funnel are different under the different permeability coefficient, and the large permeability coefficient, the greater the depth, the larger the impact area, the lower the depth in the later stage of prediction, and the lower the depth in the later stage of prediction, the lower the maximum water level in the center of the funnel is. The influence area is large, the maximum influence area is 73.00kmm2, and the maximum depth is 13.60m.m3) under different water heads, the distance between the caving fissure zone and the weak permeable layer bottom plate is not changed, the thickness of the weak permeable layer and the permeability coefficient are not changed. In order to study the influence of coal mining on the loose aquifer with different water heads, the simulation results show that under different water head conditions, the influence area of the drop funnel, the maximum water level drop depth in the center of the funnel is different, and the water head is large in the whole prediction period. The influence area and the maximum water level drop depth are great, the maximum influence area is 74.90 km2, and the maximum water level drop depth is 18.81 m.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD82

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