为了分析抽水井井底处不同粒径介质对抽水井周围水头高度的影响,基于Forchheimer公式进行计算,并将数值计算的结果与所开展的相似模拟试验结果进行对比。结果表明:Forchheimer公式中表征非Darcy流的系数口主要受抽水井井底附近区域中砂粒尺寸的影响。由理论计算可得,4种不同直径(1.65—2.36mm、0.83~1.65mm、0.35-0.83mm、0.25~0.35mm)的砂粒在距井轴水平距离1m处,压力水头的高度分别为36.02、34.95、33.94、29.84m;由试验结果可得,在井底介质同取以上4组不同直径的砂粒时,0.1m处测压管中水位的高度分别是0.450、0.439、0.424、0.413m。随着砂粒直径的减小,压力水头高度也依次减小,离井底越近处,抽水井周围水流的非线性流动现象越明显。该结论对分析不同介质环境下抽水井周围水流的非线性渗流规律具有重要意义。
In order to analyze the influence of nonlinear seepage with different medium near pum- ping well, Forchheimer equation was used for calculation and an experiment was carried out to verify the calculated results. The calculated results indicated that the coefficient β in Forchheimer equa- tion, which characterizes the nonlinear Darcy flow, mainly depends on the size of the grain at the bottom of the pumping well. When the distance from the well was 1 m, the water head height related to four different sizes of grains ( 1.65 - 2. 36 mm, 0. 83 - 1.65 mm, 0. 35 - 0. 83 mm and 0. 25-0. 35 mm) were 36.02, 34. 95, 33.94 and 29. 84 m respectively. Experimental results show that the water head height related to the grains ( 1.65 - 2. 36 mm, 0. 83 - 1.65 mm, 0. 35-0. 83 mm and0. 25 -0. 35 mm) were 0. 450, 0. 439,0. 424 and 0. 413 m at 0.1 m of the piezometer, re- spectively. With the decrease of grain size, the water head height decreased accordingly. Nonlinear flow phenomenon is more obvious near the pumping wells. This conclusion could be of considerable help for understanding the nonlinear flow within the pumping well with different materials.