基于塑性损伤的盾构隧道FRP-Key接头抗剪性能及布置方式合理性研究

Research on Shear Performance of FRP-Key Joint for Shield Tunnel and Rationality of Arrangement Based on Plastic-damage Model

为完善FRP-Key接头的设计思路并推广该接头在实际工程中的应用,利用混凝土材料的塑性损伤本构,建立了能够反映管片损伤情况和开裂过程的数值模型。基于已有试验数据,建立FRP-Key接头的实体精细化模型,以充分考虑接头与榫槽之间接触的不连续性。通过与试验结果的对比验证了所建模型的合理性和可行性。设计了7种不同的对称布置方式,以研究其对FRPKey接头抗剪性能的影响情况。重点分析了不同布置方式中管片-接头结构在剪力作用下的宏观破坏形式,探讨了布置方式对FRP-Key接头极限承载力的影响,初步判断并提出了一定轴力条件下不同破坏形式对应的接头布置范围及最佳布置方式应满足的条件,最后综合工程实际情况给出了FRP-Key接头的应用建议。数值分析结果表明:随着布置方式的变化,榫槽侧管片出现3种不同的破坏形式,其中与理论分析情况相符的布置方式应满足条件:3.125c<d2<5.625c。不同布置方式对应的极限承载力存在区别,当FRP-Key接头靠近管片边缘布置时,与理论计算结果相差最大,差值为10.52%,FRP-Key接头的最佳布置范围应满足条件:3.125c<d2<4.375c。管片-接头结构达到极限承载力时,对应的接头侧管片的竖向位移在1.6~1.7mm之间。研究结果可作为进一步探讨FRP-Key接头力学性能的参考。

In order to improve and perfect the design of FRP-Key joint and popularize the application of this joint in practical engineering,a numerical model reflecting the damage and cracking process of segment was established by plastic damage model of concrete.Based on the existing test data,the detailed model of FRP-Key joint was selected to fully consider the discontinuity of the contact between the joint and the groove.The rationality and feasibility of the model was verified by comparing experimental results.Then,seven kinds of symmetrical arrangements were designed to investigate the effect of the arrangement on the shear behavior ofthe FRP-Key joint.The macroscopic failure mode of segment-joint structure under shear in different arrangements was analyzed in detail.The effect of arrangement on ultimate bearing capacity of FRP-Key joint was discussed.The corresponding layout of different damage modes and essential conditions of the optimal arrangement were proposed under certain axial force.Advice on application of FRP-Key joint in practical project was given eventually.The numerical results indicate that three kinds of failure modes occur in the segment with groove,with the change of the arrangement.The arrangement in conformity with the theoretical analysis should meet the requirement,namely,3.125c〈d2〈5.625 c.There exist differences in the ultimate bearing capacity of different arrangements.When the FRP-Key joint is close to the edge of the segment,the difference between calculated value and theoretical result reaches 10.52%.The optimal arrangement of FRP-Key joint should meet the requirement,that is,3.125c〈d2 〈4.375 c.The corresponding vertical displacement of the segment with joint is between 1.6-1.7mm when the ultimate bearing capacity is reached.Results can provide references for further research on mechanical properties of FRP-Key joint.