沧州地区地下水盐分的时空演变与模拟研究

发布时间：2018-12-08 14:49

【摘要】：沧州地区多年来大量开采深浅层地下水,破坏了咸淡水层的界面,并导致了咸水面下移,对下部含水层有较大的影响。本文以沧州地区地下水中的盐分为研究对象,在历史资料收集分析、野外水文地质调查、取样测试分析的基础上,对比分析了历史阶段和现阶段地下水TDS的空间分布规律,探讨了沧州深层和浅层地下水中TDS的空间分布特征、演化特点及成因,并且通过对地质资料的收集建立了地下水流模型,对浅层地下水中盐分向深层地下水运移的特点进行了预测,并对各主控因素对盐分的影响程度进行了分析。结果表明：(1)从1980年到现在30余年,沧州地区深、浅层地下水的TDS均呈升高趋势,浅层水TDS高的区域从滨海向区域中部逐渐扩大,深层水TDS仍为滨海中部西部；净补给量减少和海水入侵是浅层地下水TDS增大的主要原因,超量开采地下水是深层地下水中TDS增大的主要原因。(2)由地下水水流的数值模拟可知,盐分随着地下水开采时间的增加,扩散范围逐渐增大,随地下水埋藏深度的增加影响逐渐降低。深层抽水量对盐分垂向迁移的影响最大,并促进盐分的垂向迁移；弥散度的增加也能促进盐分的垂向迁移；浅层抽水量的增加在一定程度上阻碍了盐分的垂向迁移；天窗的渗透系数在某个范围内的增大可促进盐分的垂向迁移。
[Abstract]:In Cangzhou area, groundwater in deep and shallow layers has been exploited in large quantities for many years, which has destroyed the interface of salt and light water layer, and led to the downward movement of salty water surface, which has great influence on the lower aquifer. On the basis of historical data collection and analysis, field hydrogeological investigation and sampling analysis, the spatial distribution of groundwater TDS in the historical stage and present stage is compared and analyzed in this paper, taking the salt in the groundwater in Cangzhou area as the research object. The spatial distribution characteristics, evolution characteristics and causes of TDS in deep and shallow groundwater in Cangzhou are discussed, and the groundwater flow model is established by collecting geological data. The characteristics of salt migration from shallow groundwater to deep groundwater are predicted, and the influence of main controlling factors on salt content is analyzed. The results are as follows: (1) from 1980 to now, the TDS of shallow groundwater in Cangzhou area has been increasing, and the area with high TDS in shallow water has gradually expanded from the coastal water to the middle of the region, and the deep water TDS is still in the western part of the coastal area; The decrease of net recharge and the invasion of seawater are the main reasons for the increase of TDS in shallow groundwater, and the increase of TDS in deep groundwater is mainly caused by over-exploitation of groundwater. (2) from the numerical simulation of groundwater flow, we can know that, With the increase of groundwater exploitation time, the diffusion range increases gradually, and the influence decreases with the increase of groundwater burial depth. The effect of deep water pumping on the vertical migration of salt is the greatest, and the vertical migration of salt is promoted, the increase of dispersion can also promote the vertical migration of salt, the increase of shallow water pumping hinders the vertical migration of salt to some extent. The vertical migration of salt can be promoted by the increase of the permeability coefficient of the skylight in a certain range.
【学位授予单位】：辽宁工程技术大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P641.3

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