基于CFD的土压平衡盾构刀盘开口分布特征研究

Study on the Opening Distribution Characteristics of Earth Pressure Balance Shield Cutter Head Based on CFD

土压平衡(Earth pressure balance,EPB)盾构刀盘的开口率及开口分布特征的设计是刀盘地质适应性设计的关键技术之一,直接影响开挖渣土的流动性及盾构的掘进效率。针对不同掘进地质条件下盾构刀盘开口设计的复杂性问题,利用刀盘切削渣土被改良为'塑性流变状态'的特性,运用计算流体动力学(Computational fluid dynamics,CFD)理论,建立包括渣土、刀盘、土舱和螺旋输送机在内的CFD模型,利用实际工程掘进数据验证CFD模型计算结果的正确性与方法的可行性,在此基础上,分析获得给定地质条件下相同开口率不同开口分布特征的刀盘前后渣土的压力分布规律,以及刀盘开口分布特征对盾构机刀盘开挖渣土流动性能的影响作用关系,并通过回归分析,得到刀盘开口分布特征与刀盘前后渣土压力之间的映射关系。研究为高效、稳定掘进的土压平衡盾构刀盘拓扑结构优化设计提供方法。

The opening ratio of earth pressure balance（EPB） shield cutter head and its opening distribution characteristics design is one of the most important techniques in shield cutter head adaptability design,it directly influence the liquidity of excavated soil and the efficiency of shield tunneling.Aiming at the complexity of the opening design of the EPB shield cutter head in various geological conditions,by using the properties of the cutting soil is modified as visco-plastic fluid and the computational fluid dynamics（CFD） method,the CFD model for analyzing the cutter head opening is established,which consists of the soil dregs,the cutter head,the soil cabin and the screw conveyor.Then the effective and feasible of the simulation method is validated by compared with the job site data.Based on this model,the fore-and-back pressure distribution rules of shield cutter head excavated soil in same opening ratio and different opening distribution characteristics are obtained.And the influence of opening distribution characteristics on the liquidity of excavated soil is also acquired.By regress analysis,the relationship between the fore-and-back pressure of cutter head excavated soil and the opening distribution characteristics is observed.Above research will certainly provide method for the optimization design of EPB shield cutter head.