填埋场热生成及对垃圾堆体和防渗衬垫变形强度特性影响机理

申请项目将开展垃圾填埋场有机物降解、温度变化与影响的关键科学问题研究。基于垃圾土高有机质含量和热传导水敏感特性，通过降解试验建立产源项(产气、产液、产热)方程，揭示垃圾土热传导机理和降解机制；依据垃圾土热传导特性、有机物降解产源项、能量守恒方程、非饱和土流体变形本构方程，建立耦合运移微分方程组，调查填埋场内部温度和流体压力的变化规律；进行不同恒定温度下垃圾土变形特性试验，研究主次压缩和降解压缩变形的阶段性和温度敏感性规律，利用应力路径三轴试验发展温度影响下复杂应力路径的力学模型；利用大型扭剪设备，开展温度影响下复合衬垫界面剪切特性研究，重点调查复合衬垫的剪切破坏面转移和残余强度变化规律；建立考虑温度、流体压力影响的垃圾体边坡稳定分析方法。申请项目期望在垃圾填埋体热传导特性与降解产源项变化理论、流体运移理论与压力变化规律、垃圾土变形和强度特性、衬垫界面强度特性与边坡稳定分析理论取得重点突破。

The proposed project will be carried out the key scientific researches regarding organic degradation, temperature changes and influences in landfill. Based on the high organic content and water-sensitive characteristics of thermal conductivity for the municipal solid waste (MSW), the production source term(leachate, gas, heat) equation will be established by conducting degradation experiments to reveal heat conduction and degradation mechanisms of the MSW. Based on the heat transfer characteristics of the MSW, organic degradation of the production source term, the energy conservation equation, and fluid deformation constitutive equations for unsaturated soils, the differential equations of coupled transport will be developed to investigate variations of internal temperature and fluid pressure in landfill. Under different temperatures, the stages of compression and temperature sensitivities of the primary and secondary compressions as well as degradation deformation will be studied by conducting waste deformation. A mechanical model of complex stress paths will be developed by trixial tests of stress path including temperature influences. A large torsional shear apparatus will be used to investigate the interface shear strength properties of landfill composite liner systems under temperature impact. The investigation will focus on the transfers of failure interface in composite liner systems and the interface and internal properties of large deformation or residual shear strengths for geosynthetic liner materials. A new landfill slope stability analysis method will be established by considering the influences of temperature and fluid pressures. The applications of the proposal expect to obtain some major achievements in the aspects of MSW heat conduction properties and degradation production source term theory, fluid migration theory and pressure variations, waste deformation and strength characteristics, liner interface strength properties and slope stability analysis theory.