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深层渗滤效应普遍存在于多孔介质的渗透注浆过程中,并起着非常重要的作用。基于质量守恒方程、线性滤过定律、渗流连续性方程及Darcy定律,建立了水泥浆三维锋面的理论模型;通过现场试验,研究了水泥浆三维锋面扩散运移及沉积层渗透系数的变化规律,并将试验值与模型理论值进行了对比分析。结果表明,沉积层渗透系数随水泥浆锋面的扩散运移动态变化;当注浆压力恒定时,水灰比越小,深层渗滤效应越显著,浆液扩散距离相应越短;相同扩散距离时,受重力效应的影响,注浆点源之上的沉积层渗透系数大于注浆点源之下的沉积层渗透系数;浆液扩散距离及固定位置处的沉积层渗透系数均与水灰比呈正相关。研究成果可指导工程设计,具有一定的实际应用价值。
Deep percolation effect is common in the porous medium penetration grouting process, and plays a very important role. Based on the mass conservation equation, the linear filtration law, the seepage continuity equation and the Darcy’s law, a theoretical model of the three-dimensional front of cement slurry is established. The field test is used to study the variation of the three-dimensional frontal diffusion and migration of the cement slurry and the permeability coefficient of the sediment. The experimental value and model theoretical value are compared and analyzed. The results show that the permeability coefficient of sediment changes dynamically with the diffusion and migration of the cement slurry front. When the grouting pressure is constant, the smaller the ratio of water to cement is, the more obvious the deep percolation effect is and the shorter the diffusion distance of slurry is. Under the influence of gravity effect, the permeability coefficient of sedimentary layer above grouting point source is larger than the sedimentary layer permeability coefficient under grouting point source; the diffusion distance of sediment and sedimentary layer permeability coefficient at fixed position are positively correlated with water-cement ratio. Research results can guide the engineering design, with some practical value.