泥水盾构泥膜形成二维理论分析

在各种复杂环境下采用泥水盾构法修建隧道工程，需要解决在开挖面上如何及时形成安全有效的泥膜支护问题。采用修正的剑桥模型中正常固结黏土各向等压固结曲线规律，建立泥膜固含率与有效应力之间的关系，结合圆球形颗粒孔隙理想模型的渗透率以及泥膜固含率、渗透率和比阻三者之间的关系，确立新的泥膜形成本构关系模型。将泥膜形成一维模型拓展为二维模型，基于增量分析方法分析泥膜的增长规律，给出泥膜滤失量和厚度分别与位置、时间、重度比和盾构直径等因素的关系。结果表明，修正的剑桥模型能够较好地表征泥膜压缩固结特性；对于高压泥浆，泥浆重度对泥膜增长的影响较小，但对超大直径的盾构其影响不可忽略。

Two-dimensional theoretical analysis of slurry membrane formation process in slurry shield

To build the tunnel project by slurry shield method in a variety of complex environments needs to solve the problem that how to form safe and effective slurry membrane support timely on the excavation surface. The isotropic consolidation curves of the normal consolidation clay in the modified Cambridge model is used to establish the relationship between the membrane solid holdup and the effective stress of slurry membrane. Combining this with the permeability of ideal model of round sphere particle pore and the relationships among the membrane solid holdup, permeability and specific resistance of slurry membrane, a new constitutive model for the formation process of slurry membrane is established. The one-dimensional model is expanded to two-dimensional one, and the incremental analysis method of the formation process of slurry membrane is also given to study the increasing rules. Based on this, the relationship between slurry membrane filtration loss, and factors such as location, time, unit weight ratio and shield diameter are established. The results show that the modified Cambridge model could well characterize the compression consolidation properties of slurry membrane. Under high operating pressure, unit weight of slurry has little effect on membrane growth; but its influence cannot be ignored for super-large diameter shield.