群井回灌渗滤液条件下填埋场水分迁移规律研究

Analysis of Moisture Movement in Landfill Site under Leachate Recirculation with Vertical Wells

为研究群井回灌渗滤液条件下填埋场内部水分迁移规律,基于已有的考虑生化降解的城市固体废弃物(MSW)力-液-气耦合一维沉降模型,并考虑到垃圾的分层填埋造成渗滤液的水平向渗透系数大于竖向渗透系数,忽略渗滤液的竖向流动,建立了填埋场群井回灌渗滤液时的液相运移方程,推求出常水头和常流量补水条件下的解析解,并以常水头回灌渗滤液为例分析了填埋场内水压变化规律。结果表明:填埋场内部生化反应造成水压初期降低,之后垃圾降解速率减慢和渗滤液回灌充分造成水压增大,且回灌水头越大、井距越小,水压增大越快。

To study the moisture migration of the landfill site under the condition of leachate recirculation with vertical wells ,the flow equation of leachate is established based on one-dimensional settlement equation by considering hydraulic-gaseous coupling effect and degradation of municipal solid waste （MSW ） as well as ignoring the vertical flow of leachate when the leachate permeability in horizontal direction is greater than that in vertical direction for layered landfills .Then , the analytical solution under constant head and constant flow recirculation is got ,and the transport law of leachate is stud-ied with the constant head recirculation as an example .The results show that the liquid pressure is decreased first by bio-chemical reactions ,and then increased due to the leachate recirculation and the decrease of waste degradation rate .Si-multaneously ,the liquid pressure is increased faster with the increase of recirculation head and decrease of well space .