江汉平原典型含水层水文地质参数反演

Estimation of Hydrogeological Parameters for Representative Aquifers in Jianghan Plain

含水层参数对于定性分析区域地下水资源评价、数值模拟及预报、开发利用与保护及科学管理具有重要意义,而江汉平原水文地质参数求解的研究却相对较少.2015年江汉平原1∶50 000水文地质调查项目完成杨林尾图幅与陆溪口图幅,选择杨林尾图幅和陆溪口图幅中的4个代表性钻孔,分别做了3组抽水试验和一组压水试验.对抽水数据使用Dupuit公式法结合抽水稳定阶段数据求解含水层参数,同时利用Aquifer Test软件中Theis标准曲线法、直线图解法对抽水试验中非稳定条件下抽水数据对含水层参数求解,得到孔隙水含水层渗透系数及弹性给水度;利用压水试验工程规范求解基岩裂隙含水层的渗透系数.探讨了利用非稳定抽水试验条件下求解含水层参数方法的可行性及该方法的优势.计算结果表明:杨林尾镇浅层(20.264.55m)含水层渗透系数为0.075m/d,弹性给水度为5.8×10^(-2);深层(138160m)含水层渗透系数为9.89m/d,弹性给水度为2.3×10^(-5);陆溪口镇浅层(19.436.4m)含水层渗透系数1.26m/d,弹性给水度为1.1×10^(-1);基岩渗透系数为0.012m/d.通过结果对比分析发现对于单孔非稳定抽水试验,对前期水位降深数据筛选分析,同样可以利用非稳定井流理论反演含水层参数,结果比较可靠.

Hydrogeological parameter inversion is very important for the analysis, numerical simulation and forecast, utilization and protection of regional groundwater resource evaluation. However, the relevant researches of Janhan plain are not enough. The Yanglinwei map and the Luxikou map of the Jianghan plain 1∶50000 hydrogeology survey projects were completed in 2015. The widely distributed boreholes had provided reliable information for exploring the local hydrogeological conditions. In this study, pumping test was conducted in three representative boreholes and packer test was conducted in one representative borehole. The software Aquifer Test associated with Theis model and Cooper ＆ Jacob model were used to estimate the aquifer parameters associated with the transient pumping test data. In addition, the Dupuit model was also used to calculate the aquifer parameters with the quasi steady-state pumping test data. Finally, the feasibility and advantages of different methods proposed in this study are also thoroughly discussed. The results show that the hydraulic conductivity of the shallow aquifer in Yanglinwei is 0.075 m/d and the corresponding storage coefficient is 5.8×10-2. The hydraulic conductivity and the storage coefficient of the deep aquifer are 9.89 m/d and 2.3×10-5. The hydraulic conductivity and the storage coefficient of the shallow aquifer in Luxikou are 1.26m/d and 1.1×10-1. The average hydraulic conductivity of the fractured rocks is 0.012m/d. It was also found that for a pumping test without an observation well, the selected drawdown data inside the well can also be used to estimate the aquifer parameters and the results are reliable.