大沽河咸水入侵区氯离子浓度、矿化度与地层电阻率关系实验研究  

An Experimental Investigation of Relationship of Chloride Concentration and Mineralization with Resistivity in Saltwater Intrusion Zone of Dagu River

作　　者：孟庆生[1,2] 佟雪[1] 郑西来[1,2] 李状[1] 樊玉清[1,2] 

机构地区：[1]中国海洋大学环境科学与工程学院,山东青岛266100 [2]中国海洋大学海洋环境与生态教育部重点实验室,山东青岛266100

出　　处：《中国海洋大学学报（自然科学版）》2015年第5期87-92,共6页Periodical of Ocean University of China

基　　金：水利部公益性行业科研专项(201301090)资助

摘　　要：针对大沽河水源地海水入侵问题,以现场采集的咸、淡水样品和14组人工配制水样,以及现场取回的含水层砂样,进行了咸淡水驱替试验和电阻率测试。试验结果表明:电阻率对离子浓度、矿化度的变化存在敏感区,当Cl-浓度小于500mg/L或矿化度小于1 000mg/L时,Cl-浓度或矿化度的微小变化都会引起电阻率的显著改变;各离子浓度与电阻率均呈现负相关关系,相关系数均大于等于0.987;单一Cl-指标确定的电阻率阀值为44Ω·m,与其它研究区相差较大,不能作为示范区判断海水入侵的标准;矿化度指标与电阻率具有很好的相关性,相关系数为0.988,建立的电阻率阀值与实际相吻合,可以用来衡量海水入侵程度和预测入侵范围,但在试验过程中要尽量保证砂样矿物成份符合实际,即充分考虑地层中矿物成份引起的电性影响。A combination of salt-fresh water displacement experiment and resistivity measurement test was performed to evaluate seawater intrusion in downstream of Dagu River aquifer media. To delineate the relation- ship between resistivity and the concentration of C1 and mineralization, the field samples of salt water, fresh- water, and in-suit sand were collected, and also, 14 artificial seawater samples were prepared to carry out the experiment. The results show that resistivity is extremely sensitive to the changes of mineralization and the con- centration of each ion. When the concentration of C1- is less than 500 mg/L or the mineralization is less than 1 000 mg/L, a small change of the mineralization or the concentration of C1- will cause a significant change of resistivity. There exists negative correlations between the concentration of each ion and the resistivity, and the correlation coefficient is no less than 0. 987. However, the corresponding resistivity which is 44 Ω m is much higher than others which were obtained by single index of C1 concentration in experiments of other study areas, and can＇t be used to judge the seawater intrusion in study area. And we also find that the mineralization as a significant parameter has closer relation with resistivity, the correlation coefficient is 0. 988, and the resistivity threshold value which is obtained by the relationship is coincident with the actual measured resistivity using the field seawater samples. So, the mineralization index can be used to determine the extent and rang of seawater in- trusion, but more attention should be paid to the electrical effect caused by mineral elements in the formation in order to ensure the accuracy of measuring resistivity during the experiments.

关 键 词：咸水入侵 驱替试验 电阻率 矿化度 

分 类 号：P641.7[天文地球—地质矿产勘探]