泥水平衡盾构机气垫仓内岩屑的快速排出对于保证施工安全和提高掘进效率至关重要,已有研究主要集中在岩屑在排浆管中运输的运动特性,而从气垫仓进入排浆管直至排出的完整过程却往往被忽略,因此现有研究对于指导实际工程还存在局限性.基于CFD-DEM(computational fluid dynamics-discrete element method)计算流体力学-离散单元耦合计算方法并结合实际工程建立了可以完整反映气垫仓内岩屑排出的数值计算模型,对比了不同冲刷管布设情况下(垂直距离h1、水平距离h2和转角β)岩屑的排出情况,总结了不同因素对岩屑排出率的敏感度.研究结果表明排出率随着h,的增加而减小,随着h2和β的增加而增加,三个因素的平均敏感度排序从大到小依次为h1(1.6)＞h2(0.79)＞β(0.61),因此在实际工程中降低冲刷管高度是提高岩屑率最有效的措施.研究结果可为优化冲刷管的布设和制定相关施工措施提供实用参考.
Sensitivity Analysis of Factors Influencing the Cuttings Discharged Ratio in Slurry Shield Based on CFD-DEM Method
The rapid discharge of cuttings from the air cushion chamber is crucial for the construction safety and excavation efficiency of the slurry shield,previous studies have mainly focused on the transport characteristics of cuttings in the slurry discharge pipe,while the complete process of cuttings entering the slurry discharge pipe from the air cushion chamber until its discharged is often overlooked.Based on the CFD-DEM(computational fluid dynamics-discrete element method)coupling calculation method and combined with the actual project,a numerical calculation model that can fully reflect the discharge of cuttings in the air cushion chamber was established.The discharged ratio of cuttings under different scouring pipes layouts(vertical distance h1,horizontal distance h2 and rotation angle β)was compared,and the sensitivity of different factors to the discharged ratio of cuttings was summarized.The results show that the discharged ratio of cuttings decreases with the increase of h1,and increases with the increase of h2 and β.The average sensitivity order of the three factors is h1(1.6)＞h2(0.79)＞β(0.61).Therefore,reducing the height of the scour pipes is the most effective measure to improve the cuttings discharged ratio in practical engineering.The research results can provide practical reference for optimizing the layout of scouring pipes and formulating relevant construction measures.
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