不同降雨条件下氯化物在饱和粉砂中的迁移趋势分析

Trend Analysis of Chloride Migration in Saturated Silty Sand under Different Rainfall

针对降雨可影响地下水流场及污染物迁移的问题,基于FEMWATER饱和及非饱和土体中地下水三维溶质迁移数值模型,以安徽省淮北市某电厂为例,利用不同的降雨条件(年、月、日)及水位变动条件模拟与预测氯化物在饱和带中的迁移规律,并与无降雨时的氯化物浓度做了对比分析。结果表明,月、日降雨条件下的浓度变化曲线最接近,第一年末与日降雨相差约10%,到第三年末相差至30%;而年降雨得到的浓度变化结果与日降雨第一年末、第三年末分别相差20%、40%,无降雨时第三年末相差接近90%;在不考虑降雨的条件下,污染物较难渗入地下,水平迁移明显与考虑降雨的情景下相差较大;地下水位变动较大的区域,应考虑降雨的影响,从模拟计算效率、精确度和可行性出发,月降雨可作为较优选择。

For the issue of groundwater flow and contaminant migration affected by rainfall,taking apower plant in Huaibei City of Anhui Province for an example,trend analysis of chloride migration in saturated zone was studied based on FEWATER module of saturated and non-saturated solute transport numerical model under the conditions of annual,month and daily rainfall data and the fluctuation of groundwater table.Through comparative analysis of the chloride concentration,the results show that chloride concentration curve was similar between month and daily rainfall;the difference of chloride concentration was about 10%in the end of the first year,and 30%in the end of the third year;the difference was about 20%and 40%respectively between annual and daily rainfall.Moreover,the difference was nearly 90%under the condition of no rainfall;the chloride was difficult to be transported into saturated zone under the condition of no rainfall;the lateral migration of the contaminant was greatly affected by the rainfall infiltration;the impacts of rainfall should be considered in the area where groundwater table has great fluctuations;in addition,the month rainfall is the optimum choice from the aspects of simulation efficiency,accuracy and feasibility.