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一、前言根据田间排水工程设施和机耕的要求,我国农田通常分割成长条形,长宽比一般为4～8。本文讨论的是这种农田地下水不稳定运动问题。过去的排水计算往往采用地下水蒸发与地下水位关系指数n=1、2、3,并忽略排水沟(管)处“渗出段”的影响,这种简化与排水实际并不相符。实际农田地下水一维不稳定运动具有下列特点:
I. Preface According to the requirements of field drainage engineering facilities and machine-driven, the farmland of our country is usually divided into long strips with the aspect ratio of 4 ~ 8. This article discusses the problem of unstable groundwater movement in this farmland. In the past, the calculation of drainage was often based on the index of relation between groundwater evaporation and groundwater table n = 1, 2 and 3, and the influence of “seepage section” at the drainage ditch (pipe) was ignored. This simplification was not in accordance with the actual drainage. The actual one-dimensional instability of farmland groundwater has the following characteristics: