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为了研究渗滤液水位以下产气对孔隙压力的影响,从孔隙气在渗滤液水位以下特定的流动状态出发,采用峰值产气模型,结合了达西定律、理想气体状态方程和多孔介质流体动力学理论,建立了渗滤液水位以下考虑产气作用的气液迁移模型。运用差分法对产气引起的气液迁移问题进行了数值求解。计算结果表明,渗滤液水位以下垃圾体的产气对孔隙压力的影响主要有渗滤液渗流引起的附加孔隙压力和水位升高引起的附加孔隙压力,按孔隙气所处阶段的不同可以分为孔隙气被封闭时孔压积聚阶段、孔隙气突破孔隙水封闭时的孔压急剧消散阶段以及由对流作用控制的气液运移阶段;高产气速率、高渗滤液水位和低渗透系数都会使得垃圾体内产生较高的孔隙压力;降低填埋场内渗滤液水位是减小产气对孔隙压力影响的有效措施。
In order to study the effect of gas production on pore pressure below the leachate water level, the peak gas generation model was adopted based on the specific flow regime of porous gas below the leachate level. Darcy’s law, ideal gas equation of state and porous media hydrodynamics Theory, a gas-liquid migration model considering the role of gas generation below the leachate level has been established. The differential method is used to solve the problem of gas-liquid migration caused by gas production. The results show that the effect of gas production on the pore pressure of leachate below the water level is mainly due to the additional pore pressure caused by seepage of leachate and the additional pore pressure caused by the rising of water level. According to the stage of pore gas, When the gas is closed, the pore pressure accumulates, and the pore gas breaks through the stage of rapid dissipation of pore pressure when the pore water is closed and the gas-liquid migration stage controlled by convection. The high gas production rate, high leachate filtrate level and low permeability coefficient all make the garbage in vivo Resulting in higher pore pressure; reducing landfill leachate water level is to reduce the effect of gas production on pore pressure effective measures.