渗滤液的防渗处理是填埋工程

渗滤液的防渗处理是填埋工程最重要的研究问题之一。本文在对填埋场防渗技术研究现状讨论分析的基础上，通过理论分析、室内试验、现场检测、数值模拟以及工程实践相结合，系统研究了粘土固化注浆帷幕对渗滤液的抗渗阻滞作用机理及规律，全面分析了帷幕在填埋场中应用的长期环境效应，主要研究内容如下： (1)粘土固化注浆帷幕对渗滤液的抗渗性能。对浆液配比、渗滤液浓度、pH值等对粘土固化浆液结石体渗透性能的影响进行了室内试验，首次给出了结石体渗透系数与粘土加量和水泥加量之间的函数关系式，研究了帷幕对不同污染物(重金属离子、有机物)的抗渗效果和阻滞特征，并分析了其渗透性能变化的微观作用机理。 (2)粘土固化注浆帷幕对污染物的吸附性能和机理。本文首次将吸附性能引入防渗帷幕的功能作用，通过大量的吸附平衡试验分析了浆液配比、地下水环境(温度、pH值、盐度等)和用量对帷幕吸附污染物性能的影响，研究了帷幕对污染物的吸附规律和去除特征，结果表明粘土固化注浆帷幕对污染物的吸附符合Freulldlich吸附模式，为建立粘土固化注浆帷幕、充分发挥其吸附性能提供了理论基础。 (3)污染物在粘土固化注浆帷幕中的迁移转化机理，以及不同污染物在帷幕中的迁移特征。污染物在帷幕及地下水环境中的迁移、吸附与交换以及转化过程中，将发生物理、化学和生物变化，从而使渗滤液得到进一步净化。此外，研究了不同污染物在帷幕中的迁移速度、浓度分布和赋存状态等迁移特征，揭示了帷幕对污染物的阻滞规律。 (4)污染物在粘土固化注浆帷幕中运移的水动力数学模型，并进行模拟计算。概括了渗滤液及污染物在帷幕(土壤)及地下水中运移的基本方程式，对地下水渗流的连续性方程进行了详细推导，首次推求了基于时间变化的渗透系数的渗滤液流动微分方程，讨论了其定解条件和数值解法。在试验成果的基础上，建立了污染物在粘土固化注浆帷幕中的水质方程和水流方程，采用ADI法进行差分求解并编写了相应的计算机程序，讨论了相应参数值的确定，对渗滤液的渗流运动和污染物的迁移转化进行了数值模拟计算，揭示了帷幕对污染物的阻滞规律，完整系统地研究了渗漏量和污染物迁移转化基本参数的影响效果。 (s)粘土固化注浆帷幕应用于填埋场防渗工程中的长期环境效应。首次系统地从试验和模型两个方面研究了粘土固化注浆帷幕对渗滤液及污染物的控制作用，从防渗作用和净化作用两个方面研究了帷幕对渗滤液及污染物控制的长期环境效应，并分析了帷幕的抗酸稳定性和高耐腐蚀性。 (6)粘土固化注浆帷幕在填埋场防渗工程中的应用情况。首次将这种垂直防渗体系引入填埋场工程，取得了良好的经济效益和社会环境效应。实践证明，在这种特殊的构筑物中建立垂直防渗体系，是行之有效的，其防渗效果能够满足填埋场设计的防渗要求。
电加热器
To prevent seepage of leachate from landfill into environment is one of the most important problems for municipal solid waste (MSW) landfill. Based on the engineering practice and a series of methods including theoretical analysis, laboratory tests, site observation and numerical simulation, the retention mechanism and anti-seepaging capability of clay-solidified grouting curtain (CSGC) to leachate are systematically researched and the environmental effects of CSGC applied in MSW landfill is completely evaluated. The main research contents and results in mis paper are summarized as following:1.Permeability of clay-solidified grouting curtain to leachate. The influence of components and their ratio of grouts, concentration and pH of leachate on permeability are studied with laboratory experiment, and the functional formula of hydraulic conductivity and content of clay and cement is brought up. Then the effects and the characters of CSGC anti-seepage to contaminant such as heavy metals and organic matter are studied.2. Adsorption mechanism and property of clay-solidified grouting curtain to contaminant. In this paper, adsorption is firstly described as a function of CSGC, and the effects of component and their ratio of grouts, leachate environment such as temperature, pH and salinity on adsorption are studied with equilibrium experiment. The evidence shows that the adsorption mechanism of CSGC to contaminant conforming to Freundlich Adsorption Model. It provides the theory for establishing CSGC and utilizing adsorption mechanism.3. Transportation and transformation mechanism of contaminates in clay-solidified grouting curtain and contaminates’ transportation features in CSGC. Contaminates in the process of transporting in CSGC and groundwater, of adsorbing, of exchanging, and of transforming willtake place physical, chemical and biological reaction, which makes leachate purified further. Moreover, the features of contaminates’ transporting speed, concentration distribution, and contaminates existing form in CSGC are studied.4. Mathematical models and their solutions for hydrodynamic transport of contaminant in clay-solidified grouting curtain. The base formula of transportation that of leachate and contaminant in CSGC and the formula of ground water seepage are put forward. The leachate transport equation with time-varying hydraulic coefficient is established and its mathematical solution is obtained and programmed by finite difference ADI method. By means of mathematical simulation based on the laboratory experiments, the assessment of anti-seepaging and retention effect of leachate seepage and basic parameters describing contaminant transportation and transformation are carried out.5. Longtime environmental effects of clay-solidified grouting curtain applied in MSW landfill. The longtime environmental effects of CSGC controlling leachate anti-seepaging and contaminant are probed systematically at the first time in two aspects of anti-seepaging and purifying, and the durability of CSGC is also studied with experiment in the paper.6. Application of clay-solidified grouting curtain on anti-seepaging engineering in MSW landfill. It has brought great social, economic and environmental benefits in the construction of MSW landfills in Nanchang and Changsha. The application shows that CSGC can meet the design requirement and the sohe poisonous substances well.