岩溶介质非均质性对钻孔水物化指标垂向变化的影响  

Effects of heterogeneity of karst media on the hydrochemical parameters from vertical borehole logs

作　　者：刘绍华[1] 汤庆佳[1] 杨利超[1] 章程[1] 苗迎[1] 

机构地区：[1]中国地质科学院岩溶地质研究所/国土资源部、广西壮族自治区岩溶动力学重点实验室/联合国教科文组织国际岩溶研究中心,广西桂林541004

出　　处：《中国岩溶》2015年第6期577-585,共9页Carsologica Sinica

基　　金：国家自然科学基金项目(41472239,41172231);广西科学研究与技术开发项目(桂科能1298018-6);中国地质调查局地质调查项目(12120114006301);中国地质科学院岩溶地质研究所所控项目(2014032,2015003,2015020)

摘　　要：岩溶介质具有较强的非均质性,其地表及地下的岩溶结构形态多样。通过对钻孔结构描述、钻孔水物化性质分析,不仅能够掌握区域上岩溶含水层的结构特征,而且对于岩溶地下水演化过程的揭示亦有重要作用。文章以桂林岩溶水文地质试验场西南部峰丛山区与峰林平原交界处的钻孔为例,通过野外便携式多参数仪原位测试钻孔垂向水物化指标(pH值、水温T、电导率EC),探索浅部(地面以下约50m内)地下岩溶较为发育条件下钻孔水物化指标的垂向变化特征,揭示岩溶介质非均质性对钻孔垂向水物化指标的影响。结果表明:岩溶地区小范围内不同钻孔间的水物化性质有所差异,且岩溶发育相似的钻孔(如ZK4/ZK5、ZK7/ZK8),其水物化指标垂向变化具有一定的相似性,但不同指标(T、pH、EC)的变化幅度存在差异;钻孔水物化性质受到试验场区岩溶介质结构非均质性的控制,即岩溶介质结构影响了地下水的赋存条件和水力联系而导致水物化性质的差异;在对岩溶地区地下水物化性质进行研究时应充分考虑岩溶介质的非均质性特征,根据实际的水文地质条件选取具有代表性的钻孔含水段进行取样和监测。Karst media are highly heterogeneous, which has been manifested both on surface and subsurface. In general,the description of rock formation and the analyses of physical and chemical properties of a bore-hole groundwater may help to understand the structural features of an aquifer and associated ground water e-volution. This study is conducted on the basis of groundwater vertical logging data derived from the bore-holes situated on the border between peak cluster mountain area and peak forest-plain in the southwest of Guilin Karst Experimental Site. On this site, the influence of the heterogeneity of karst media on physical and chemical indexes of the aquifer by using portable multi-parameter device which basically logged pH, temperature （T）, electrical conductivity （EC）at different holes. The results showed that in the small-scale karstic aquifer,the physical and chemical properties measured in-situ are different across the area~ and these parameters obviously varied at depth in one borehole. Moreover, it is noted that the groundwater in the bore- holes with analogously karstified conditions shows similar properties which suggests that the heterogeneity of the karst mediahas an influence on the groundwater occurrence and hydraulic connection. This should be full- y taken into account during the research of karst groundwater and associated aquifer properties; and the groundwater sampling and monitoring can be focused on the conductive zones in the boreholes, in order to re-flect flow dynamics and hydrogeological setting of karst aquifer.

关 键 词：岩溶介质 非均质性 钻孔水物化指标垂向变化 水力联系 桂林岩溶水文地质试验场 

分 类 号：P641[天文地球—地质矿产勘探]