Integrating Hydraulic, Tracer, and Geophysical Methods to Image Flow-Channeling Behavior in Fractured Bedrock

集成水力、示踪剂和地球物理方法对裂隙基岩中的水流通道行为进行成像

• 批准号: 0207720
• 负责人: Matthew Becker
• 金额: $ 11.84万
• 依托单位: SUNY at Buffalo
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-08-01 至 2005-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0207720&HistoricalAwards=false
• 关键词: Integrating; Hydraulic; Tracer; Geophysical; Methods

Becker0207720It has long been hypothesized that ground water flows through bedrock fractures in a channelized manner, implying that contaminated ground water may be very difficult to detect or predict. To date, flow channeling at the field scale has been detected only in boreholes or tunnels. This research will yield, for the first time, map-view images of channeling in a fracture plane. Saline tracer will be injected into a single saturated sub-horizontal bedding-plane fracture, and its distribution will be mapped using high-resolution ground-penetrating radar. Experiments will be conducted in floor of a limestone quarry so that the water table is shallow and there is no overburden to obstruct the radar signal. Several forced gradient hydraulic configurations will be used to allow both low-resolution time-variant and high-resolution time-invariant imaging of saline tracer. Monitoring holes will simultaneously detect saline concentration, so that the efficacy of borehole monitoring in the presence of channeling can be evaluated. Finally, fluorescent dye will be injected into the fracture and the rock above the fracture removed so that flow channeling can be mapped directly. Ground penetrating radar, monitoring well concentrations, dye distribution, and hydraulic testing will be used to calibrate a finite difference ground-water flow and transport model. This model will be used to investigate errors associated with monitoring ground-water pollution and design hydraulic and tracer tests to characterize effective porosity in fractured bedrock. Although the geophysical techniques employed in this research are not practical for most contaminated sites, tracer and hydraulic methods developed from this project could have a significant impact on how contaminated sites in fractured bedrock are monitored, characterized, and remediated.

Becker0207720长期以来，人们一直假设地下水以渠道化的方式流过基岩裂缝，这意味着受污染的地下水可能很难检测或预测。 迄今为止，仅在钻孔或隧道中检测到现场规模的流窜。 这项研究将首次产生断裂面通道的地图视图图像。 盐水示踪剂将被注入单个饱和的次水平层理面裂缝中，并使用高分辨率探地雷达绘制其分布图。 实验将在石灰石采石场的地面进行，这样地下水位很浅，并且没有覆盖物阻碍雷达信号。 将使用几种强制梯度水力配置来实现盐水示踪剂的低分辨率时变和高分辨率时不变成像。 监测孔将同时检测盐水浓度，以便评估存在窜流情况下钻孔监测的效果。 最后，将荧光染料注入裂缝中，并去除裂缝上方的岩石，以便可以直接绘制流道图。 探地雷达、监测井浓度、染料分布和水力测试将用于校准有限差分地下水流和传输模型。 该模型将用于调查与监测地下水污染相关的误差，并设计水力和示踪剂测试来表征裂隙基岩的有效孔隙度。 尽管本研究中采用的地球物理技术对于大多数污染场地并不实用，但该项目开发的示踪剂和水力方法可能会对裂隙基岩污染场地的监测、表征和修复产生重大影响。