Abstract

Fractal theory demonstrates significant merit in the feature expression of forms of matter in nature. This study uses fractal theory to study the backfill grouting of a shield tunnel. The seepage path was considered as a seepage mesh inserted into the rock-soil mass. For the fractal features of the seepage mesh, the formulas for the diffusion distance and the pressure contribution of grout were derived. The results showed that the diffusion equations of different grout patterns (Newtonian fluid and Bingham fluid) were of a uniform form after calculation, and the equations for the pressure distribution of grout with a change in radius were identical. The diffusion distance of grout increased with increasing grouting time, and there was no indication that the development of diffusion distance tended to be gradual; the downward tendency of the grout diffusion velocity was not moderated. The segment pressure increased with an increase in the diffusion distance. With a constant diffusion distance, a greater grouting pressure produced a greater segment pressure. The favorable performance of grout was attributed to an appropriate mixture ratio. An improper mixture ratio resulted in a smaller reinforcement area in the stratum, which impaired the stability of the shield tunnel.

摘要

分形理论在自然界中物质形式的特征表达中表现出显着的优点。本研究采用分形理论研究盾构隧道回填注浆。渗流路径被认为是插入岩土体中的渗流网。针对渗流网格的分形特征，推导了浆液扩散距离和压力贡献公式。结果表明，不同灌浆模式（牛顿流体和宾汉姆流体）的扩散方程经计算得到一致的形式，随半径变化的灌浆压力分布方程一致。浆液的扩散距离随着注浆时间的增加而增加，没有迹象表明扩散距离的发展是渐进的；灌浆扩散速度的下降趋势没有减弱。段压力随着扩散距离的增加而增加。扩散距离恒定时，灌浆压力越大，管片压力越大。灌浆的良好性能归因于适当的混合比。配比不当导致地层中的加固面积变小，影响了盾构隧道的稳定性。