砂卵石地层盾构泥浆渗透成膜细观分析及离散元模拟

为研究泥水平衡盾构在砂卵石地层成膜困难的问题,采用自制设备,开展泥浆渗透试验,观察泥浆在卵石地层中形成泥膜的过程,对泥浆颗粒在地层中的堆积形态进了细观分析,探究泥浆渗透成膜机理。基于FLUENT-EDEM耦合方法,建立泥浆渗透数值模型,结果表明：泥膜的三种渗透状态取决于泥浆地层颗粒比；相同条件下泥浆的渗透深度随泥浆密度增大而减小,随着泥浆压力的增大而增大,但泥浆压力的影响较小。数值模拟结果可反映室内试验现象,结论可为盾构施工参数的选取提供参考。

Meso-Analysis and Discrete Element Simulation of Slurry Infiltration Filter Cake Formation of Shield in Sandy Pebble Stratum

In order to study the problems of slurry shield filter cake formation in sandy pebble stratum, the self-made equipment was used to carry out permeability tests to observe the process of filter cake formation in the sandy pebble stratum. The morphology of the accumulation of slurry particles in the stratum has been analyzed in detail to explore the mechanism of slurry infiltration and filter cake formation. Based on the FLUENT-EDEM coupling method, a slurry infiltration numerical model is established. The results show that the three permeability states of the filter cake depend on the particle ratio of the slurry and stratum. Under the same conditions, the slurry penetration depth decreases with the increase of slurry density, and increases with the increase of slurry pressure. The influence of pressure is small. The numerical simulation results can reflect the phenomenon of indoor experiments, and the conclusions can provide reference for the selection of shield construction parameters.