盾构隧道粘度时变性浆液壁后注浆渗透扩散模型

Back-filled Grouts Diffusion Model of Shield Tunnel Considering Its Viscosity Degeneration

在假定注浆浆液为粘度时变性流体,并在盾尾间隙影响厚度范围内均匀柱面扩散的前提下,应用达西定律对盾构壁后注浆渗透范围及浆液对管片造成的压力进行了理论推导,得到了浆液扩散半径及对管片产生压力的计算式。通过具体实例,对比分析了是否考虑粘度时变性2种条件下浆液扩散半径及对管片产生压力的计算结果,以及不同胶凝时间下浆液扩散半径及对管片产生压力的计算结果。分析结果表明:2种条件下,浆液扩散半径及对管片产生的压力随注浆压力、注浆时间的变化规律不尽相同,粘度时变性对浆液扩散半径及对管片产生的压力影响显著,可通过调整浆液配比来改变粘度时变性,进而影响浆液扩散半径及对管片产生的压力,但浆液对单位面积管片的压力几乎不受粘度时变性的影响。

Assuming that the back-filled grouts are viscosity degeneration fluids, and the grouts diffuse with cylinder surface in view of the influence of tail gap, the grouts diffusion area and thepressure on shield tunnel segments were derived with Darcy law. As a result, the formulae to calculate the radius and the pressure were acquired. Through specific examples, the diffusionradii and the pressures on segments when considering and neglecting the grouts viscosity degeneration were compared, as well as in the condition of different gel time. The results showthat the change rules of the diffusion radii and the pressures on segments are not the same when considering or neglecting the grouts viscosity, and viscosity degeneration has a significantinfluence on the diffusion radii and the pressures on segments, which can be controlled by grout formulae, however, the pressures on unit areas of segments are almost not affected by groutsviscosity degeneration.