摘要
温度与气体压力是衡量垃圾填埋场稳定性的2个重要指标,进行温度-气体压力耦合研究有利于揭示二者在填埋场内部的时空演化规律。以广州兴丰垃圾填埋场为研究背景,推导了多孔介质温度-气体压力耦合数学模型。采用COMSOL Multiphysics有限元模拟软件,结合监测数据,检验了数学模型的适用性和合理性,预测了封场后至稳定化过程中兴丰垃圾填埋场温度与气体压力的时空动态演化特征。研究结果表明：场区内一定深度处的温度在封场后5-7 a内快速上升至峰值并保持3-4 a左右,随后缓慢减少直至稳定,呈现＂中间低,两头高＂的规律;封场后某一时刻场区内的温度水平方向上基本一致,只在左右边界附近发生较小的波动;场区内一定深度处的压力在封场后1-2 a内快速上升至峰值并保持1-2 a左右,最后缓慢下降;某一时刻场区内的压力在水平方向上的分布规律与温度场相当;气体主要沿垂直方向传播,整体上气压自顶部往底部减小。分析成果可为填埋场设计、施工、运营及管理提供指导性意见。
Temperature and gas pressure are two important indicators about stabilization in landfill, coupling of the temperature with gas pressure are conducive to reveal the rule of temporal and spatial evolution inside the landfill. Taking Xingfeng Landfill in Guangzhou as an example,coupled mathematical model about temperature and gas pressure was derived,which was examined by the finite element simulation software-COMSOL Multiphysics combined with the monitored data. Dynamic evolution characteristics of temperature and gas pressure were analyzed through the whole stabilization process after post-closure. Results showed that the temperature at a certain depth of field area would quickly increase to a maximum after 5-7 years of post-closure,and maintain around the peak for 3-4 years,then slowly decrease to stabilization,showing a ＂middle low,two high＂ rule. Horizontal temperature would be roughly equal at certain depth,with the exception of the area near the symmetrical boundary（left and right side）. Gas pressure at a certain depth of field area would quickly increased to a maximum after 1-2 years of post-closure,and maintain around the peak for 1-2 years,then slowly decrease to stabilization,with horizontal rule similar to that of temperature. Gas is mainly transmitted along the vertical direction,and the overall pressure decreases from the top to the bottom. The results can provide guidance for the landfill design,construction,operation and management.
出处
《环境科学与技术》
CAS
CSCD
北大核心
2015年第10期196-203,共8页
Environmental Science & Technology
基金
广东省科技计划项目(2005A30402004)
