盾构克泥效浆液成分与渗透扩散研究

克泥效工法常在盾构隧道近接既有建筑物穿越工程中被引进作为控制地层位移的一种辅助工法,克泥效浆液在地层的渗透扩散性对盾壳与地层间环向间隙填充效果有着重要影响,克泥效浆液的流变性能与其微观成分对其流动性有着重要影响。本文基于对克泥效浆液流变性能与微观成分分析,研究了浆液性能变化。进一步结合宾汉姆流体砂土渗流公式与数值计算模型,分析了浆液性能对渗透效果的具体影响,并验证数值模型可靠性与合理性。结果表明:(1)各组克泥效浆液样本在宾汉姆本构下的非线性回归系数均大于0.95,塑性黏度与屈服强度会随着水粉比的减小而增大。(2)克泥效浆液主要成分为石英、斜长石、伊利石、钾长石,随着A液水粉比的增加,克泥效水化产物斜长石增加,而伊利石的含量减小。(3)克泥效浆液会在25s左右占满环向间隙,而后再向地层中发生渗透扩散,地层中浆液体积分数增速随时间而减小,直至增速降为0。(4)随A液水粉比增大、地层渗透系数增加、注浆压力增加,克泥效在地层渗透距离均会增加。理论渗透值与数值模型计算值误差在各工况下的平均误差控制在10%以内。

Study on the Composition and Permeation Diffusion Performance of Clay Shock Slurry

The clay shock method is introduced as an auxiliary method for controlling strata displacement in shield tunnel crossing projects near existing buildings. The permeability and diffusion of clay shock in the strata have a significant impact on the filling effect of the circumferential gap between the shield shell and the strata. The rheological properties of clay shock and its microscopic composition have a significant impact on its fluidity. This article studies the changes in slurry performance based on the analysis of the rheological properties and microscopic components of the slurry. Further combining the bingham fluid sand seepage formula and numerical calculation model, the specific impact of slurry performance on seepage effect was analyzed. The reliability and rationality of the numerical model were verified. The results show that: (1) The nonlinear regression coefficients of each group of clay shock slurry samples under bingham constitutive model are greater than 0.95, and the plastic viscosity and yield strength will increase with the decrease of water-powder ratio. (2) The main components of clay shock slurry are quartz, albite, illite and orthoclase. With the increase of water-powder ratio, hydration product albite increases, while the content of illite decreases. (3) The clay shock slurry will fill the circumferential gap in about 25 seconds, and then undergo infiltration and diffusion into the stratum. The increase in the volume fraction of the slurry in the formation decreases over time until the increase rate drops to 0. (4) As the water-powder ratio increases, the permeability coefficient of the formation increases, and the grouting pressure increases, the clay shock slurry will increase the diffusion distance of the stratum. The average error between the theoretical and numerical value under various operating conditions should be within 10%.