基于VBA的宁夏引黄灌区暗管排水间距计算方法研究

暗管排水工程是控制灌区地下水位,防治耕地盐碱化的主要技术手段。【目的】综合考虑排水条件、排水目的等因素,选择合适的计算方法计算暗管间距。【方法】对几种常用的暗管间距计算方法进行了理论分析并总结了其适用条件,编写了基于VBA的计算程序以实现不同计算方法的优选并确定相应的暗管间距。在此基础上,选取宁夏引黄灌区2个典型暗管排水工程案例进行了分析计算。【结果】稳定流状态下,当kH/q≤100时,宜选择阿维里扬诺夫-瞿兴业公式计算暗管间距,当kH/q>100时,宜选择Hooghoudt公式计算暗管间距;非稳定流状态下,以治渍为目的地区选择按地下水位下降速度计算暗管间距,以防治盐碱化为目的地区选择按排蒸比计算暗管间距。【结论】利用VBA开发的程序可以解决暗管间距计算过程中较繁琐的迭代、累加等计算问题,操作便捷,实用性强;非稳定流方法更适合于宁夏引黄灌区暗管排水间距的计算,银北灌区宜按排蒸比计算暗管间距,银南灌区宜按地下水位下降速度计算暗管间距。

Calculation Method Research on Pipe Drain Spacing of Ningxia Yellow River Irrigation Region Based on VBA

Subsurface pipe drain project is a vital technique to control the groundwater table for prevent the saline-alkali of cultivated land in the irrigation area.【Objective】For the calculation of the pipe drain spacing, the appropriate calculation method should be selected by considering the drainage conditions and drainage purposes comprehensively.【Method】Several commonly theoretically calculation approaches were analyzed and their applicative conditions were summarized in this paper. Then the program based on VBA was compiled for optiming calculation methods and calculating the pipe drain spacing. And two typical cases of subsurface pipe drain project were analyed from Ningxia Yellow River Irrigation Region.【Result】If kH/q≤100, the Aviryanov-qu Xingye formula was more suitable; If kH/q>100, the Hooghoudt formula should be selected in the steady flow state. The pipe drain spacing for the aim to control groundwater table may be determined with groundwater drawdown speed; the pipe drain spacing for the aim to prevent and treatment the saline-alkali soil may be determined with the ratio of drainage water quantity and evaporation capacity in the unstable flow state.【Conclusion】The program compiled with VBA can solve the problems such as cumbersome iterative and cumulative, which was a convenient operation and has remarkable practicability. The method of unsteady flow state is more available for Ningxia Yellow River Irrigation Region. The pipe drain spacing would be calculated according to the ratio of drainage water quantity and evaporation capacity in Yinbei irrigation area; and it would be calculated according to the speed of groundwater drawdown speed Yinnan irrigation area.