【摘要】 由于砂性地层孔隙率大且孔隙分布的巨大差异性,地层渗透性能具有显著的各向异性特征,所以导致盾构施工同步注浆浆液渗透扩散也具有明显的各向异性和非均质性。针对砂性富水地层盾构同步注浆渗透扩散距离预测方面存在的问题和不足,提出虚拟微元流体柱状结构模型和等效流管浆液渗流模型,构建盾构同步注浆渗透扩散理论模型,建立了浆液渗透扩散距离的理论解。系统研究了渗透性富水地层盾构同步注浆浆液渗透扩散特性及其与浆液黏稠度、土体孔隙比、注浆压力等参数的相关性。结果表明,注浆渗透距离与浆液黏稠度成反比、与土体孔隙比和注浆压力成正比;一定的工程条件下,同步注浆压力存在相对合理的取值区间,压力过小不利于盾尾空隙充填,压力过大则易引发地表冒浆及周边环境安全风险。研究结果应用于实际工程,取得了良好技术效果。更多还原

【Abstract】 Due to the large void ratio and the great difference of pore distribution in sandy stratum, the permeability of stratum is of significant anisotropy, which leads to the obvious anisotropy and heterogeneity of diffusion of synchronous grouting in shield construction. With regard to the problems and shortcomings in predicting the penetration and diffusion distance of shield synchronous grouting in sandy and water rich stratum, the virtual micro element fluid column structure model and the equivalent flow pipe slurry seepage model are proposed; the penetration and diffusion theoretical model of shield synchronous grouting slurry is constructed; and the theoretical solution of slurry penetration and diffusion distance is established. The permeability and diffusion characteristics of synchronous grouting slurry and its correlation with slurry viscosity, soil void ratio and grouting pressure are systematically studied. The results show that the grouting penetration distance is inversely proportional to the slurry viscosity, and directly proportional to the soil void ratio, porosity and grouting pressure. Under a certain engineering condition, there is a relatively reasonable range of synchronous grouting pressure. If the grouting pressure is too low, it is not conducive to the filling of shield tail gap. Meanwhile, if the pressure is too high, it is easy to result in surface grouting and the safety of surrounding environmental under risk. The research results have been applied to the practical project and achieved good technical results.更多还原