基于优势流效应的填埋场渗沥液回灌过程预测

渗滤液回灌对于补充垃圾堆体水分及加速降解稳定化具有重要的促进作用,垃圾堆体的非均质性和大孔隙特征造成了渗沥液流动过程出现显著的优势流效应.以双渗透率模型为基础,开展典型回灌工艺条件下垃圾堆体中渗沥液的分布规律预测研究.预测结果表明:一定限度内增大回灌速率、回灌频率、回灌量、初始含水量等因素可提高渗滤液的影响深度、入渗量和贮水率;优势流模型较传统的单域模型,区分了具有高导水性的裂隙域和高持水性的基质域,渗滤液可以更快地通过裂隙入渗、流动和排出,更符合垃圾堆体内水分多域流动行为模式;裂隙域和基质域的水分质量交换项是动态平衡的,随深度而减小.

Prediction of Leachate Injection Process in Landfill based on Preferential Flow Effect

Leachate injection has an important role in promoting water replenishment and accelerating degradation and stabilization of landfill. The inhomogeneity and large pore characteristics of the garbage piles have caused significant dominant flow effects in the leachate flow process. Based on the dual permeability model, this paper carried out a prediction study on the distribution law of leachate in the waste heap under typical recharge process conditions. The prediction results show that increasing the injection rate, injection frequency, injection volume, initial water content and other factors within a certain limit can increase the influence depth, infiltration volume and water storage rate of the leachate. Compared with the traditional single domain model, the preferential flow model distinguishes the fracture domain with high water conductivity from the matrix domain with high water retention. Leachate can infiltrate, flow and discharge through cracks more quickly, and it is more in line with the flow behavior model of water multi-domain in waste. The water mass exchange term in the fracture and matrix domain are dynamically balanced and decreases with depth.