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粘土衬垫的防渗性能和吸附阻滞性能对卫生填埋场防渗系统工作性能有着重要影响。通过建立一维对流-弥散模型,分析了渗透系数、扩散系数、入渗强度、吸附能力对渗漏量及衬垫击穿时间的影响。考虑实际工程的复杂性,建立能反映土体分层、土体非均质性、地下水运动及宏观弥散等复杂因素影响的污染物运移二维分析模型,并对各参数的敏感性进行分析。计算结果表明,保持填埋场在低渗滤液水位下运行,对提高衬垫的防渗效果及耐久性有重要意义;受材料本身性质、施工质量等因素的影响,粘土衬垫的渗透系数变异性往往较大,渗透系数提高一个数量级时,衬垫击穿时间显著缩短;渗透系数恒定时,衬垫击穿时间与材料阻滞因子成线性变化关系;地下水分布及运动情况对污染物运移及分布有重要影响,地下水位越低,竖向入渗越明显,入渗区下部土体的吸附性能发挥越充分,到达地下水及下部土体的污染物浓度越低。
The impermeability and adsorption retardation of clay liner have an important influence on the performance of sanitary landfill seepage control system. Through the establishment of a one-dimensional convection-dispersion model, the effects of permeability coefficient, diffusion coefficient, infiltration strength and adsorption capacity on leakage and liner breakdown time were analyzed. Considering the complexity of the actual project, a two-dimensional model of pollutant transport that can reflect the complex factors such as soil stratification, soil heterogeneity, groundwater movement and macroscopic dispersion is established, and the sensitivity of each parameter is analyzed . The calculation results show that keeping the landfill site operating at low leachate water level is of great significance to improve the anti-seepage effect and durability of the liner. Depending on the nature of the material itself and the construction quality, the permeability coefficient of the clay liner varies While the permeability coefficient increases by one order of magnitude, the liner breakdown time is significantly shortened. When the permeability coefficient is constant, the liner breakdown time is linear with the material retardation factor. The distribution of groundwater and the movement of pollutants And the distribution has an important impact, the lower the groundwater level, the more obvious vertical infiltration, the lower reaches of the infiltration zone soil adsorption performance to play more fully reach the groundwater and the lower the concentration of pollutants in the lower soil.