考虑浆液扩散路径的多孔介质渗透注浆机理研究
Infiltration grouting mechanism of porous media considering diffusion paths of grout
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摘要: 多孔介质注浆的扩散方式以渗透注浆为主,传统的多孔介质渗透注浆往往忽略了浆液渗透过程中的扩散路径,导致理论结果与实际偏差较大。基于对多孔介质浆液渗透过程中扩散路径分析,根据浆液扩散运动方程,建立了考虑浆液扩散路径的多孔介质渗透注浆模型,设计了一套多孔介质渗透注浆扩散模拟实验装置,并采用常规注浆材料-水泥浆液,获得不同被注介质渗透率及不同注浆速率下的注浆压力的时空变化规律。研究结果表明:考虑浆液扩散路径的多孔介质浆液渗透注浆模型计算值为试验值的1.1~1.3倍,计算值与试验值误差在允许的范围之内,所建模型可较好的描述了浆液渗透扩散过程;不考虑浆液扩散路径的多孔介质渗透注浆模型计算值为试验值的1.8~3.2倍,显著高估了注浆扩散过程的浆液压力。研究成果成功用于青岛地铁砂层治理工程,因此,在多孔介质渗透注浆扩散设计中应充分考虑浆液扩散路径。Abstract: The diffusion mode of grouting in porous media is mainly infiltration grouting, and the traditional infiltration grouting in porous media often neglects the diffusion paths in the process of slurry infiltration, resulting in a large deviation between the theoretical results and the actual ones. Based on the analysis of the diffusion paths in the slurry infiltration process of porous media, an infiltration grouting model for porous media considering slurry diffusion paths is established according to the equation for slurry diffusion. A set of infiltration grouting simulation experiment device for porous media is designed. The slurry-cement slurry is used to obtain the spatiotemporal variation of grouting pressure under different permeabilities of grouting media and grouting rates. The results show that the calculated values of slurry grouting model are 1.1 ~ 1.3 times the experimental ones, and the error between the calculated and experimental values is within the allowable range. The model can be used to describe the diffusion process of slurry infiltration. The calculated values of the infiltration grouting model for porous media, without considering the diffusion paths of slurry, are 1.8 ~ 3.2 times the experimental ones, and the slurry pressure of the grouting diffusion process is significantly overestimated. The research results have been applied in sand layer management of Qingdao metro. Therefore, the diffusion paths of slurry should be fully considered in the design of infiltration grouting in porous media.