地下水流平面二维水头资料用于三维模拟的误差分析

用一个傍河剖面二维潜水模型来分析这一误差对结果的影响。通过边界元法计算出稳定流场作为初始流场,运用变步长有限差分法求解边界水位瞬时下降后的流场当作实际值。再把初始流场的水头在垂向平均(相当于勘探资料)作为初始条件,重新求解边界水位瞬时下降后的流场得到近似解。比较近似解的潜水面、井水位和河流入渗量与实际值的误差,结果表明：近似解的潜水面位置和井水位均低于实际值但误差较小;而河流入渗量却大于实际值且误差较大,尤其是初期误差可达到70％以上;随着时间延续这些误差均逐渐减小。直到水流稳定时而完全一致。

Error Analysis of 3-D Groundwater Model Using 2-D Data Obtained From Field Survey

In most evaluation of groundwater resources with 3 D simulation model, the 3 D data have to be replaced by the 2 D data as limitation of exploration expenditure. Some errors may occur. In the study, effects of these errors on results of simulation are examined by employing a vertical 2 D transient model of aquifer near a partially penetrating stream. To resolve the transient model, the initial head distribution in vertical section is obtained by solving a 2 D stable flow model with boundary element method (BEM). The actual flowfield (ATF) is got by solving the transient model with the initial head distribution. Averaging initial head distribution at vertical direction gives the average initial heads or initial well heads that only distribute along the direction of cross stream. Then approximate flowfield (APF) is got by resolving the transient model in which the initial condition is replaced by initial well head. Through comparing the water table, resulted well head (i.e. average head) and stream recharge of the approximate flowfield with these of real flowfield, it is shown that the height of water table and well head in approximate flowfield is lower than in real flowfield, that the recharge of stream in approximate flowfield is much greater than in real flowfield and that these errors decrease with time lasting.