Abstract

Shield tunnel is widely adopted in the metro construction, and backfill grouting is the significant part. With power-law fluid grouts as the study object, a cylindrical infiltration diffusion model and spherical infiltration diffusion model are developed by applying the generalized Darcy law and theories of seepage mechanics based on the displacement effect of grout on groundwater. Through examples, the impact of factors including grouting pressure and formation permeability coefficient in the spherical displacement infiltration diffusion model on diffusion radius, flow rate, total pressure of grout in segments, and uniform equivalent pressure in grout diffusion area (grout pressure per unit area in a segment) is analyzed. The result shows that, the diffusion speed, injection flow rate and the pressure received in segments increase with an increase of the grouting pressure. Meanwhile, as the injection time increases, the flow rate of grout under conditions of different grouting pressure all decreases, and a sharp decrease exists. The diffusion speed and grouting pressure are positively correlated to the permeability coefficient, and with the increasement of the injection time, the diffusion displacement of grout in different permeability coefficient varies increasingly, the increase amplitude of the pressure acting on the segment by grout increases gradually.

摘要

盾构隧道在地铁建设中被广泛采用，其中回填注浆是其中的重要组成部分。以幂律流体浆液为研究对象，应用广义达西定律和基于浆液对地下水的驱替作用的渗流力学理论，建立了圆柱入渗扩散模型和球形入渗扩散模型。通过实例分析了球形置换入渗扩散模型中注浆压力、地层渗透系数等因素对扩散半径、流量、段内浆液总压力、浆液扩散面积均匀等效压力（单位面积内的浆液压力）的影响。段）进行分析。结果表明，扩散速度，随着注浆压力的增加，注入流量和分段接收的压力增加。同时，随着注浆时间的增加，不同注浆压力条件下的注浆流量均呈下降趋势，并出现急剧下降。扩散速度和注浆压力与渗透系数呈正相关，随着注入时间的增加，不同渗透系数的浆液扩散排量变化越来越大，浆液作用在管片上的压力增加幅度逐渐增大。