基于分形理论的盾构壁后注浆压滤扩散模型

Pressure filtration diffusion model of shield tunnel back-filled grouting based on fractal theory

基于有效应力原理,考虑注浆过程中浆液对于土体压缩造成的孔隙减小现象,基于分形理论提出盾构隧道壁后注浆的压滤扩散模型,并分析注浆压力、注浆量和孔隙率分形维数对浆液压降曲线及管片压力的影响。研究结果表明:浆液压力随扩散半径增加逐渐减小,管片压力随注浆压力增大大致呈线性增大;孔隙率分形维数对管片压力影响显著,管片压力随孔隙率分形维数增大而增大;考虑渗透模型(本文模型)管片压力在不同注浆压力下均大于未考虑渗透模型的管片压力,且注浆压力越大,两模型结果差值越大,因此,当在注浆压力较大时,应考虑浆液的渗流效应。

Based on the principle of effective stress,and the phenomenon that the slurry reduces the pores caused by the compression of the soil when the grouting process was considered.Based on fractal theory,a pressure filtration diffusion model for shield tunnel back-filled grouting was proposed.The grouting pressure,grouting volume and porosity fractal dimension were analyzed.The results show that the slurry pressure gradually decreases with the increase of the diffusion radius,and the segment pressure gradually increases linearly with the increase of the grouting pressure.The pore fractal dimension has a significant effect on the segment pressure;the segment pressure increases with the increase of the porosity fractal dimension;considering the permeation model(the model in this article),the segment pressure is greater than that without considering the permeation model at different grouting pressures,and the greater the grouting pressure,the greater the difference between the two models when the grouting pressure is large,the seepage effect of the slurry cannot be ignored.