基于CFD-DEM的盾构泥浆管道排渣特性参数影响规律研究

Study on the Influence Law of Slag Discharge Characteristic Parameters of Shield Mud Pipeline Based on CFD-DEM

盾构用泥水循环系统排渣时,其排渣特性直接影响排渣效率,进而影响盾构的施工效率。针对实际工程施工中,泥浆管道的排渣过程不能直接观察,内部泥浆和岩渣的运动规律也不明确的问题,以广州地铁7号线三模式盾构地铁隧道施工为背景,采用CFD-DEM耦合方法建立管道泥浆和岩渣耦合的数值仿真模型,通过单因素影响实验方法,分析泥浆流速、密度、黏度及管道直径等泥水循环系统关键参数对泥浆管道排渣特性的影响规律。结果表明:岩渣颗粒在管道中的运动形态大部分为在管道底部做推移运动,经过弯管部分时会对弯管外侧造成冲击,泥浆经过弯管时在内弯管处流速增大;随着泥浆流速、泥浆黏度的增加与管道直径的减小,泥浆压力损失以二次方的形式增加,泥浆压力损失随着泥浆密度的增加而线性增加。

When the slurry circulation system of the shield machine is discharged,its slag discharge characteristics directly affect the slag discharge efficiency,and then affect the construction efficiency of the shield machine.In view of the problem that the slag dis⁃charge process of the mud pipeline cannot be directly observed in the actual construction,and the movement law of the internal mud and rock slag is not clear,the numerical simulation model of pipeline mud and rock slag coupling was established by using the CFD-DEM coupling method against the background of the three-mode shield subway tunnel construction of Guangzhou Metro Line 7.The influence of key parameters of the slurry circulation system such as slurry flow rate,density,viscosity and pipeline diameter on the slag discharge characteristics of mud pipeline was analyzed through the experimental method of single factor influence.The results show that most of the movement patterns of rock slag particles in the pipeline are moving at the bottom of the pipeline,and the impact on the outside of the bent pipe will be caused when passing through the bent part;the flow rate of the slurry increases at the inner bend as it passes through the bend;with the increase of slurry flow rate,slurry viscosity and decrease of pipeline diameter,the slurry pressure loss increases in the form of quadratic,and the slurry pressure loss increases linearly with the increase of slurry density.