降解和压缩作用下垃圾土气体渗透率非线性定量表征模型研究

Study of Nonlinear Quantitative Characterization Model of Gas Permeability under Degradation and Compression

垃圾土的气体渗透特性是填埋气体灾变控制与资源化利用的重要参数.基于垃圾土气体渗透率-孔隙度关系的幂函数模型和复合压缩模型,建立了考虑降解和压缩作用的垃圾土气体渗透率定量表征模型,分析了压缩系数、生化降解应变和生化降解速率常数等参数对气体渗透率定量表征模型的演化规律和影响机理,并探讨了应变对孔隙度,以及幂指数对气体渗透率模型的影响规律.分析结果表明:随着压缩系数的增大,气体渗透率数值减小幅度较大,可达到2个数量级;生物降解应变对气体渗透率定量表征模型的影响主要是后期的降解沉降阶段,且随着生物降解应变的增大,气体渗透率不断的减小;生物降解速率常数对气体渗透率定量表征模型的影响主要在中间降解阶段,且随着生物降解速率常数的增大而减小;随着应变的增大,孔隙度降低的幅度较大,数值可达到初始值的0.4倍;随着应变的增大,气体渗透率是不断减小,且减小幅度随着幂指数的增大而不断增大,可达2个数量级.

Gas permeation characteristic of municipal solid waste(MSW)is an important parameter for the control and resource utilization of landfill gas.Based on the power function model of gas permeability and porosity and composite compression model relationship of MSW,a quantitative characterization model of gas permeability of MSW considering degradation and compression is established.The evolution rule and influence mechanism of the gas permeability quantitative characterization model with compression coefficient,biochemical degradation strain and biochemical degradation rate constant are analyzed.The effects of strain on porosity and power exponent on gas permeability model are also discussed.The results show that with the increase of compression coefficient,the gas permeability decreases greatly,which can reach two orders of magnitude.The influence of biochemical decomposition strain on the quantitative characterization model of gas permeability is mainly at the later stage of degradation settlement;and the gas permeability decreases with the increase of biodegradation strain.The influence of biodegradation rate constant on the quantitative characterization model of gas permeability is mainly in the intermediate degradation stage and decreases with the increase of biodegradation rate constant.With the increase of strain,the porosity decreases greatly;and the value can reach the initial value of 0.4 times.As the strain increases,the gas permeability decreases;and the decrease amplitude increases with the increase of power exponent,which can reach two orders of magnitude.