论文部分内容阅读
为分析抽水井附近水流的非达西流动,采用装填均质河砂的扇形密闭水槽模拟承压含水层,开展了外边界水头恒定条件下的定流量抽水试验,获得到了水流稳定流动时的水头降深曲线。通过比较试测水头降深与达西流动理论水头降深,以及比较相邻两压力传感器之间的平均水力梯度与相同流速下的达西水力梯度,进行了非达西流动的判别,比较结果发现本试验条件下存在明显的非达西流动现象。同时,应用基于Izbash方程的非达西稳定流动水头降深解析解,对不同流量下的试验数据进行了拟合分析,发现抽水流量对非达西稳定流动的Izbash方程系数值影响较小。通过不同平均方法获得了描述本试验中非达西流动的Izbash方程系数的适宜取值为k=7.17×10-7,n=1.65,此时不同抽水流量下拟合水头降深曲线与试测水头降深曲线吻合良好,表明基于Izbash方程的非达西稳定流动水头降深解析解可较好地描述抽水井附近的非达西径向稳定流动。
In order to analyze the non-Darcy flow of water near the pumping wells, a confined aquifer filled with homogeneous river sand was used to simulate the confined aquifer and a constant-flow pumping test was carried out under the constant water head of the outer boundary to obtain the water head Decrease the curve. By comparing the measured head-down with the Darcy flow theory head-down, as well as comparing the average hydraulic gradient between two adjacent pressure sensors and the Darcy hydraulic gradient at the same flow rate, the discrimination of non-Darcy flow was carried out. The comparison results It is found that there are obvious non-Darcy flow phenomena in this experimental condition. At the same time, the analytic solution of non-Darcy stable flow head-down based on Izbash equation is applied to fitting test data under different flow rates. It is found that the pumping flow has little effect on the Izbash equation coefficient of non-Darcy stable flow. The suitable values of coefficients of Izbash equation describing the non-Darcy flow in this experiment were obtained by different averaging methods as k = 7.17 × 10-7 and n = 1.65. At this moment, The good consistency of the head-down curve indicates that the non-Darcy stable flow head-down analytical solution based on the Izbash equation can well describe the non-Darcy radial steady flow near the pumping well.