土压平衡盾构刀盘开口率与刀盘前后压差的关系

Relationship Between Aperture Ratio and Fore-and-Back Pressure of EPB Shield Cutter Head

盾构刀盘开口率是决定刀盘拓扑结构的关键参数,在刀盘的设计中具有重要的作用.为研究盾构刀盘开口率的设计问题,将切削渣土-盾构刀盘作为一体,构建了包括刀盘前部已经切削下来的渣土、刀盘本体、泥土舱和螺旋输送机4部分在内的四联体计算模型,在此基础上,应用流体力学方法模拟了土体-盾构刀盘系统流场静压力和流场速度分布,并与施工数据比较,验证了模型的正确性.应用该模型,研究了不同开口率对刀盘前后压差变化的影响.研究表明:刀盘前后压差随着开口率增大而逐渐减小,在保持掌子面稳定的情况下,螺旋输送机排土速度也随着开口率增大而逐渐减小.对文中所涉及的地质条件,刀盘开口率在30%和50%时,刀盘的支护压力与该地质所对应的地应力较为接近,对掌子面支护比较有利.

The aperture ratio of cutter head is a key parameter in shaping the topological structure of cutter head. In order to design aperture ratio, a four-body computing model, consisting of soil dregs cut from head front, substance of cutter head, soil compartment and screw conveyor, was proposed. Based on this model, hydrostatic pressure and hydrostatic velocity distribution were simulated by applying fluid mechanics technique. The mechanical model was effectively verified through comparison with construction data. Influences of aperture ratio on interface stability and fore-and-back pressure of the shield machine were studied by the model. Results show that fore-and-back pressure decreases gradually with the increase of aperture ratio. In the case of maintaining interface stability, screw conveyor speed also decreases gradually as aperture ratio increases. Under the geological conditions in this article, the interface support pressure is close to the corresponding geological stress when the aperture ratio of cutter head ranges from 30% to 50%, which benefits interface support.