通量上边界与水头上边界方法的地下水流系统模拟对比

Comparison of Flux Upper Boundary and Given Head Upper Boundary in Simulation of Groundwater Flow Systems

水头上边界方法(简称水头法,GHB)给定了潜水面形态和固化了排泄点,限制了不同地下水流系统模式的形成与转化。分别用数值法进行了通量上边界(简称通量法,FUB)与水头上边界的地下水流系统对比模拟。结果表明:嵌套式多级地下水流系统(Tóth典型模式)在运用水头法和通量法进行系统转化模拟时,得出的水流模式可能相似或完全不同;通量法在条件(盆地形态、入渗强度等)改变时潜水面能够自动形成,从而得出不同变化条件下的水流系统特征;水头法由于给定了潜水面和固化了排泄点,在改变盆地其他因素时,盆地补给(排泄)也发生同步改变,此时地下水流模式不是单因素变化的结果,因此在给定条件下不能得出完整的地下水流系统变化模式。基于通量法与水头法在地下水流系统模拟中的优势与不同,在进行盆地地下水流系统理论和实际研究时,应该综合2种方法的特点,结合实际资料条件进行方法的选取与应用。

Due to the given water table and discharge points,the analysis of groundwater flow patterns and their transformation are limited using given head boundary （GHB）.T＆#243;thian’s typical modes of groundwater flow-systems are simulated numerically using GHB and flux upper boundary （FUB）,showing that：1）When analyzing groundwater flow patterns and their control factors,the flow patterns simulated using FUB and GHB may be completely different or perhaps similar,while other conditions are the same;2 ）for the FUB,the water table can be automatically formed under given conditions,thus we can get the characteristics of different flow-systems with a change of infiltration intensity,hydraulic conductivity,or depth of a basin;3）for the GHB,the recharge into and discharge from a basin （i.e.,the flux through the upper boundary）change with changes in hydraulic conductivity and basin depth,entailing corresponding changes in groundwater flow patterns,so that the results obtained with GHB do not reflect these changes.Therefore,based on the respective advantages of GHB and FUB,during the theoretical and practical study of the groundwater flow-system,the advantages of these two methods and the practical information should be comprehensively taken into consideration to select the appropriate method.