多场耦合作用下垃圾填埋场内液气运移规律研究

Landfill gas (LFG) emission and explosion, leachate leakage and diffusion, landfill deformation and instability are the main hazards in municipal solid waste (MSW) landfills, which are closely related to the migration and blocking of leachate and LFG. In this research, the effects of MSW composition, degradation age and saturation on leachate and gas permeability are investigated through large-scale permeability tests, and the multi-field interaction mechanisms in landfills are studied by large-scale model testing. Based on the above, considering the influences of biodegradation on MSW engineering characteristics and the anisotropic permeability of landfill leachate and gas, a solid-liquid-gas-chemical-thermo coupling model can be established. Then, the landfill leachate-gas migration law can be developed considering coupling multi-field effects. Moreover, the control methods of the leachate-gas migration can be developed under the optimal degradation environments, and the design criteria of the landfill leachate and gas collection and removal systems will be established. It can be seen that this research is the important foundation for evaluating the safety and environmental effects of landfills, and is also the key basis for rational design of waste landfills. Moreover, this project can help deepen our knowledge on the leachate-gas coupling migration in anisotropic and degradable materials, and promote the theory development of the leachate-gas coupling migration in landfills.

填埋气体的泄露与爆炸、渗滤液的渗漏与扩散以及垃圾堆体的变形与失稳是目前垃圾填埋场存在的主要灾害问题，这与填埋场内液、气运移及其受阻密切相关。本课题通过研发大型垃圾土渗透仪和导气装置，研究垃圾土组分、龄期和饱和度等因素对垃圾土液气渗透特性的影响规律；通过大型室内模型试验，研究垃圾体固、液、气、化、热相互作用机制；考虑生物降解对垃圾工程特性衰变的影响以及液气渗透特性的各向异性，建立填埋体固-液-气-化-热多场耦合作用模型；然后，分析多场耦合作用下填埋场内液气运移规律，提出填埋场最优降解环境的液气运移调控措施及导排系统设计方法。本课题的研究对填埋场的安全性和环境效应的分析，以及现代卫生填埋场的科学设计都有重要的意义；本课题将促进人们对高度非均质、可降解材料中液气运移特性的深入认识，推动垃圾土中液气耦合运移理论的发展和完善。