基于赫巴流体的盾构同步注浆三维扩散机理

The 3D diffusion mechanism of shield synchronous grouting based on Hershel-Bullkley fluid

盾构施工中复杂的地质环境和各种类型的开挖断面使得注浆施工控制较为困难。本文基于赫巴流体本构模型,分析了同步注浆阶段的浆液充填扩散与渗透扩散过程。建立了涵盖充填扩散与渗透扩散过程的盾构隧道壁后同步注浆浆液3D扩散理论模型,并分别推导了相对应的计算公式。使用工程实例和注浆试验结果验证了该模型,并对影响浆液扩散的主要因素:浆液密度、盾尾间隙厚度、注浆压力、注浆率和地层渗透系数进行了敏感性分析。研究表明:在环向充填阶段,浆液在注浆孔两侧的消散速率随着浆液密度的增大而减小,而盾尾间隙厚度几乎没有影响;在轴向充填阶段,浆液充填压力随着时间的推移而消散,消散速率随着盾尾间隙厚度的增大而减小。在径向渗透扩散阶段,浆液径向渗透扩散深度随着地层渗透系数和注浆压力的增大而增大,而浆液密度和盾尾间隙厚度几乎没有影响。

The complex geological environment and diverse excavation sections in a shield tunnel pose challenges in grouting control.This paper investigates 3D diffusion mechanism of synchronous grouting in shield tunnel,using Herschel-Bulkley fluid constitutive model.A theoretical model was proposed to describe the filling diffusion and permeation diffusion processes,and derives the corresponding calculation formulas for each.It was verified by engineering examples and grouting test results.Additionally,a parametric analysis was conducted on key factors,such as grout density,shield tail void thickness,grouting pressure,grouting rate,and stratum permeability coefficient.The results show that in the circumferential filling stage,the dissipation rate of the grout at the grouting hole decreases with the increase of grout density,while the shield tail void thickness has minimal effect.In the axial filling stage,the slurry filling pressure dissipates over time,with the dissipation rate of grout gradually decreases as the shield tail void thickness increases.In the radial permeation stage,the permeation depth of the grout increases with the increase of permeability and grouting pressure,while grout density and shield tail void thickness have minimal effect.