摘要
进行河水与地下水温度示踪研究时,若采用长滤网井监测温度,在井中存在垂向水流运动(简称井中流)的情况下,井中监测到的温度不能代表实际深度处的温度,而长滤网监测井目前还在广泛应用。针对此,开展了室内物理模拟实验,以探讨井中流对温度示踪结果产生的影响。本研究采用砂槽模型模拟野外实际不同情况下的水流及温度变化条件,在均质、各向同性、完全饱水的稳定流条件下进行了三组地下水补给河水的对比实验,分别为空白实验1、监测井影响实验2以及井中流影响实验3。随后,利用获取的水位及温度数据对比分析了井中流对温度示踪河水与地下水相互作用结果产生的影响及影响机理,并根据一维垂向热运移解析解计算对比了地下水流速。结果显示实验2与实验1的所有结果基本一致,而实验3井中水流的垂向运动导致温度示踪结果与实验1所代表的实际情况发生偏差,计算流速比实际流速大83.72%。据此得出结论:在垂向水流占主导时,井中流的影响不可忽略,建议在野外研究中截断井中垂向水流通道以避免井中流对温度示踪结果的影响。
The use of heat as a tracer to investigate river-groundwater interaction has been spurred over the world. However, the effect of installment of the temperature sensors in the fully-screened wells on temperature change, which was widely used, has not been investigated. This research conducted three groups of experiments in laboratory to explore the effect of the intraborehole flow occurred in the fully-screened wells on temperature change when heat is used to trace the river and groundwater interaction. The water level and temperature data were monitored during the experiment. The results show that the fully-screened monitoring well itself had no effect on the heat tracing result, but when the intraborehole flow occurred in fully-screened well during the river and groundwater interaction, the temperature change monitored in the well at the specific depth was obviously affected. The flow velocity calculated by the measured temperature in the fully-screened well is 83.72% larger than that indicated by the monitored temperature in the sand. The results can provide the insight into the lemperature data monitoring method in field site.
出处
《水文地质工程地质》
CAS
CSCD
北大核心
2015年第5期14-21,共8页
Hydrogeology & Engineering Geology
基金
国家自然科学基金重大研究计划(91325101
91125009)
