盾构切桩弧形撕裂刀几何构型优化研究

该研究利用有限元与离散元的方法构建弧形撕裂刀切削钢筋混凝土耦合模型,并开展参数分析,探明弧形撕裂刀刃宽与刃角对刀具切削性能与损伤的影响,给出弧形撕裂刀在切削钢筋混凝土时的推荐结构设计方案。研究结果表明,刃宽与刃角对弧形撕裂刀的切削性能有显著影响,刃宽越小,刃角越小,弧形撕裂刀的刀刃越锋利,有助于提高破桩能力。但是,这样的设计带来的缺点是容易出现局部应力集中现象,导致弧形撕裂刀断裂失效和损坏。因此,刀刃宽度不应过大或过小,综合考虑有效应力和切削力,实际工程中设计弧形撕裂刀时,建议刀刃宽度控制在4~5 mm之间,刃角建议控制在80~90°之间。研究结论可为未来盾构切桩的弧形撕裂刀选型优化提供参考和借鉴。

In this study,the coupling model of cutting reinforced concrete with arc tearing cutter is constructed by using finite element method and discrete element method,and the parameter analysis is carried out to find out the influence of arc tearing knife edge width and edge angle on tool cutting performance and damage.The recommended structure design scheme of arc tearing cutter when cutting reinforced concrete is given.The results show that the blade width and edge angle have significant influence on the cutting performance of arc tearing cutter,and the smaller the blade width is.The smaller the blade angle is,the sharper the blade of the arc tearing knife is,which is helpful to improve the pile breaking ability.However,the disadvantage of this design is that it is easy to appear local stress concentration,which leads to fracture failure and damage of arc tearing cutter.Therefore,the blade width should not be too large or too small,and the effective stress and cutting force should be taken into account.When designing arc tearing cutters in practical engineering,it is recommended that the blade width should be controlled between 4 mm and 5 mm,and the edge angle should be controlled between 80°and 90°.The research conclusion can provide reference for the optimization of arc tearing knife selection of shield cutting pile in the future.