成层介质中填埋场渗滤液水位的瞬态求解

Transient saturated depth of landfill leachate in layered drainage media

现代填埋场排水层或覆盖层设计时,对排水系统水位深度的估算大都针对稳定状态时的最大水位,对水位增长过程的模拟鲜有涉及。在扩展的Dupuit假定基础上推导了成层排水介质中瞬态水位计算方法,通过与稳态计算方法的对比,验证了方法的准确性。通过参数分析发现对双层排水系统来说,渗透系数减小到一定程度后,会导致水位的大幅增加,达到稳定的所需时间也越长。排水距离越长和坡度越小,达到最高水位也越滞后。合理设置排水距离和适当增加排水系统的坡度可以非常有效地控制水位深度。复合排水材料对减少最大水位深度有着重要的意义。

To design the cover system or leachate collection system of a modern landfill,steady state solutions are usually used to analyze the maximum liquid head in the drainage system,but the increment procedure is rarely involved.Based on the extended Dupuit assumption,a computational solution is presented to calculate the transient liquid head.Compared with the results calculated by Ke Han（2005）,the present method is shown to be more rational and accurate.By means of parameter analysis,it is found that in double drainage system the decrease of the permeability coefficient will cause the maximum liquid head to increase greatly,and the stable time will be longer.Reasonable drainage distance and increase of the slope will decrease the maximum liquid depth effectively.The application of the geocomposites will significantly reduce the maximum liquid depth of the drainage system.