Field Determination of Geological/Chemical Properties of an Aquifer by Cone Penetrometry and Headspace Analysis
Field Determination of Geological/Chemical Properties of an Aquifer by Cone Penetrometry and Headspace Analysis
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DOI：
10.1111/j.1745-6584.1992.tb02011.x
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发表时间：
1992-05
期刊：
影响因子：
--
通讯作者：
C. Chiang;K. Loos;R. Klopp
中科院分区：
文献类型：
--
作者：
C. Chiang;K. Loos;R. Klopp
带有孔压测量的圆锥贯入仪于1975年首次引入。它被岩土工程界普遍认为是软土地层录井最有效的工具之一。最近，传统的圆锥探测仪已经与多孔探头地下水采样器相结合，用于环境应用。该耦合系统被用来进行土壤测井、采集地下水样本和评估水力传导性，以努力确定德克萨斯州含水层中可溶性碳氢化合物羽流的范围和优先流动路径(S)。用带有光电离化检测器的便携式气相色谱仪(GC/PID)分析了由多孔探头采样器采集的地下水样品的碳氢化合物含量，以表征可溶有机羽流的程度，并提供地下水质量的现场评估。用这项技术从蒸气顶空间测量中计算出的碳氢化合物的水溶液浓度，与使用环境保护局的标准地下水分析程序在实验室中获得的直接浓度测量结果非常一致。这一现场程序使得在特征较少的区域有效地使用锥体渗透测量设备成为可能，从而允许通过顶空分析快速描绘挥发性有机羽流。通过对圆锥贯入仪测试资料的解释，找出了一条东西走向的埋藏河道。在河道的北部和南部，由于土壤类型或沉积密度的不同，土壤的水力传导性降低。对从该地区采集的地下水样本的分析证实，可溶性碳氢化合物正在沿着更具渗透性的通道运移。此外，深度选择性地下水采样记录了垂直浓度剖面的急剧变化，表明该场地的宏观垂直弥散可能可以忽略不计。
The cone penetrometer with pore pressure measurements was first introduced in 1975. It is generally regarded in the geotechnical community as one of the most efficient tools for stratigraphic logging of soft soils. Recently, the conventional cone penetrometer has been coupled with a porous probe ground-water sampler for environmental applications. This coupled system was used to perform soil logging, collect ground-water samples, and evaluate hydraulic conductivity in an effort to determine the extent and preferential flow pathway(s) of a soluble hydrocarbon plume in a Texas aquifer. Ground-water samples collected by a porous probe sampler were analyzed for hydrocarbon content by a portable gas chromatograph with a photoionization detector (GC/PID) to characterize the extent of the soluble organic plume and provide a field evaluation of ground-water quality. Aqueous concentrations of hydrocarbons calculated from vapor headspace measurements by this technique were in good agreement with direct concentration measurements obtained in the laboratory using standard EPA ground-water analytical procedures. This field procedure makes it possible to efficiently use cone penetrometry equipment in less characterized areas allowing rapid delineation of volatile organic plumes by the headspace analysis. Interpretation of the cone penetrometer test data located a buried channel on the site aligned in an east-west depositional direction. To the north and south of the channel, the soils exhibited reduced hydraulic conductivity due to their respective soil type or depositional density. Analyses of ground-water samples collected from the area confirmed that soluble hydrocarbon migration was following the more permeable channel. In addition, depth selective ground-water sampling recorded sharp changes in the vertical concentration profiles indicating that macroscopic vertical dispersion may be negligible at this site.