| Pollution control of landfill gas and its recovery have attracted the attention of the public, because over 90% municipal solid wastes were disposed by landfill and over 100 million dun landfill gases were released into environment every year.Reducing the pollutants by 10% were taken as a constrained index into the eleventh five-year plan and three systems of pollutant reduction were established during"eleventh-five"period. Clean Development Mechanism(CDM) was produced into our country. Because it just begun, it provides us opportunity and challenge, therefore, whether the LFG pollution has development value has become the focus both at home and abroad. The movement of LFG through refuse is a largely complex kinetics process. The whole process of LFG migration and evolvement were subjected to solid particles. Landfill is regarded as the unsaturated zone in this paper. On the basis of the current research, the biodegradation of organic substance and settlement in MSW were analyzed in this paper elementarily. Considering coupling analysis of seepage field and stress field, quantization research of gas pressure, saturation and sensitivity analysis of parameters in models was presented in the process of LFG extraction. It provides theoretical evidence and technique support for LFG pollution control and resource utilization. The primary produce including:(1) Mechanics mechanism and compression mechanism of landfill soil was deeply analyzed. The models of soil water characteristic curve were developed, and at the same time the sensitivity analysis of parameters in models were analyzed. The parameter's effect on water movement was researched. It provides direction to choose the basic parameters in soil water movement. (2) The effect of different landfill conpounds on waste settlement and different proportion of organic and inorganic matter in landfill was obtained through analysis on deformation of waste, it provides basic condition for further stabilish research.(3) Self-development MSW settlement experimental equipment was designed, Based on mechanisms of organic matter degradation, the degradation models was established. And degradation of organic matter and change of water and gas mass was measured. The settlement experiment was developed under four conditions (nature, tempreture, stress, rain). The relationship between settlement and time and influencing factors on organic matter degradation in MSW was analyzed,it provides the theory basis for development of models and selection of paramaters.(4) By combining the laboratory experimental study and the existing results of monitoring experiment in site, the aerogenous rate model of LFG was developed, and it was introduced into LFG migration governing equation. The LFG migration mathematical model was obtained under coupling of the stress field and seepage field. Thus it provides the science instruction to quantitative analysis of pollutant migration in landfill.(5) A Galerkin finite element algorithm is used for discreting models in this paper. The numerical scheme of coupling government equation for stress field and seepage field was given. Finite element program was used to simulate the dynamic progress. The simulated results indicate that LFG pressure is smaller when consider coupling than without. Because the stress fieldhas not considered under the non-coupling, and the landfill is buried hierarchically. So the hole strucure distribution and porosity changed by landfill weight and LFG pressure is smaller at the same time. Therefore, the coupling of two fields was considered when the gas control system optimized design and the environmental effect forecast and appraise.Based on the research results above, theory basis abour analysis on settlement of landfill site and LFG movement were provided. And the results provide technical support for stablish of landfill site and optimization design of control system in LFG.
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