多因素耦合变态混凝土浆液扩散机制及施工工艺参数优化研究

The existing grouting penetration studies of grout-enriched vibrated RCC (GEVRCC) proposed the theoretical models to predict the penetration length using grouting pressure, permeability, rheological characteristics and construction parameters. However, these models ignored the effects of the time-dependent rheological behavior of grout, the filtration, and the capillary pressure, which can significantly alternate the flow pattern, resulting in the deviation from the real grouting process. This study develops a model to account for the time-dependent rheological behavior by considering the mixture composition and proportion of the grout. A spatial distribution of the pore characteristics is established based on grouting and filtration experiment. A relationship among the pore characteristics, the capillary pressure and the fluid saturation is deduced. And the existing grouting penetration model is extended to the realistic multivariate-coupled grouting penetration model by incorporating the developed model and relationship. The FEM-DEM coupled numerical simulation is conducted to analyze the grouting penetration process and mechanism. The effects of the various construction parameters on the grouting length and fluid saturation are studied using the proposed model and the numerical simulation. The optimal combination of the construction parameters is determined to secure the uniformity and performance of the GEVRCC.

目前变态混凝土浆液扩散理论模型主要关注注浆压力影响，推导浆液扩散半径与注浆压力、渗透系数、流变指数、施工参数间的关系。但这些研究忽略了流变参数时变、渗透淤堵、毛管压力等关键因素影响，计算分析与施工实际情况偏差较大。本课题通过建立基于组分和掺量的浆液流变参数时变模型，以及基于孔隙参数-毛管力-饱和度三者关联的毛管力空间分布理论模型与淤堵孔隙结构演变描述，试图构建多因素耦合影响的碾压混凝土拌合料加浆浆液扩散模型；通过有限元-离散元流固耦合渗流数值模拟浆液渗透过程，揭示孔隙浆液流动扩散与停止的物理机制；运用该模型分析不同施工参数条件下的注浆扩散范围和饱和度，提出注浆施工参数最优指标确定方法，从而为保障变态混凝土注浆施工均匀性和提高防渗效果建立应用理论基础。

变态混凝土注浆存在施工参数缺乏规定、施工过程依赖经验、完工质量难量化评定等问题，难以满足精益施工发展需求。而传统的浆液扩散理论无法反映流变时变、渗透淤堵、注浆压密等因素影响，导致预测分析与施工实际偏差较大，影响注浆质量判断。针对以上问题，项目主要研究了（1）浆液扩散性能表征及配方优化；（2）多因素耦合浆液扩散范围理论推导及可视化试验验证；（3）注浆均匀性评价及施工参数优化馈控。研究重要成果包括（1）厘清了含多种矿物掺和料水泥浆液的时变及流变特性，确定了含矿物掺合料的浆液最佳配合比；（2）提出了考虑浆液流变时变及渗透淤堵的浆液扩散模型、最大扩散半径和注浆压力沿程分布计算公式；（3）开发了可视化实验室模拟注浆装置，获得了渗透注浆及压密注浆条件下浆液扩散规律，确定了导致浆液扩散方式转变的临界注浆压力；（4）获得了基于多重分形参数的混凝土注浆后孔隙分布异质性定量描述，明确了浆液扩散距离和注浆饱和度双指标体系表征浆液有效扩散范围，优化选取了注浆最佳施工参数组合；（5）开发了数字化注浆机械和可视化注浆质量馈控系统，实现了注浆压力、流量的精准控制和注浆位置的实时记录。本项目的意义是通过项目理论研究结合现场工程设备开发和应用，为注浆工艺参数的合理选择和注浆质量的精准控制提供理论支撑和硬件基础，切实改进了变态混凝土施工质量。