蒸发影响情况下二维不稳定流有限单元法的排水计算

The Two-dimensional Unstable Flow Finite Element Method for the Calculation of Drainage Affected by Evaporation

在内陆干旱区,由于蒸发强烈,因此在进行排水计算时,必须考虑蒸发对地下水运动的影响。推导了地下水蒸发与埋深呈线性关系时的二维不稳定流排水的Galerkin有限单元方程,并分析了新疆典型灌区的排水效果。分析认为:地下水位在排水系统和地面坡度作用下,其降落速度经历了由快到慢的过程,前2 d的累积降深平均为1.2 m,后3 d的累积降深为平均为0.9 m;农田的排水农沟间距为100 m时,排水5 d后,地下水位就可降低到2 m以下,表明排水效果较好。

In inland arid areas, when drainage is calculated, the effects of evaporation on groundwater movement should be taken into consideration due to strong evaporation. In this paper, it is deduced that Galerkin finite element equation of two-dimensional unstable flow drainage under the condition that groundwater evaporation and burial depth have linear relations and the drainage effect of Xinjiang＇s typical irrigation areas is analyzed. Through the analysis, it is assumed that under the effect of both drainage system and earth grade, the sinking velocity of the groundwater table gradually slows down and that the first 2 days cumulative drawdown averages 1. 2m while the last 3 days cumulative drawdown has an average of 0.9 m. The groundwater table can drawdown to less than 2 m in 5 days when the spacing of the farm＇s drainage ditch is 100 m which reveals effective drainage ability.