盾构隧道混凝土管片接头抗弯与抗剪性能试验研究

Experimental Research on Bending and Shear Resistance of Concrete Segment Joints in Shield Tunnels

混凝土管片的接头部位在使用过程中,会受到轴力、弯曲力矩和剪切力的共同作用,为能够全面了解混凝土管片接头处受不同外力下作用下的力学性能。根据研究特点,设计三组试验分别为极限承载能力、极限弯矩、剪切试验。针对混凝土管片接头有、无斜向螺栓工况,从管片接头受压区高度、最大张开度以及张开角度的试验数据角度,分析混凝土管片接头处轴力和极限弯矩之间的变化关系。采用有斜向螺栓逆剪切、有斜向螺栓顺剪切以及无斜向螺栓剪切的三种对比试验方式,开展管片接头破坏状态和接头相对错动量分析。研究表明,有无斜向螺栓下的混凝土管片接头处受压区高度和极限弯矩均随着轴力的增加呈现线性增长的趋势,最大张开度和张开角均随着轴力的增加呈线性减弱的趋势;有斜向螺栓连接的管片接头,其相对错动曲线存在平台段,同时受顺剪下的平台段要明显长于逆剪下的平台段。通过管片接头顺剪切和逆剪切破坏对比试验的研究,可较为全面地揭示管片接头部位的抗弯、抗剪切性能的宏观变形规律,其研究结果可为盾构隧道管片接头构造的合理选择提供参考。

The joint of concrete tunnel segments is simultaneously subjected to the combined action of axial force,bending moment,and shear force.In order to fully understand the mechanical performance of the concrete segment joint under different external forces,three sets of tests,including ultimate bearing capacity,ultimate bending moment,and shear tests were designed according to the research characteristics.Subsequently,considering the working conditions of the concrete segment joints with or without oblique bolts,the experimental data of the compressive zone height,maximum opening width,and opening angle of the joint were analyzed from the perspective of the relationship between axial force and ultimate bending moment.Finally,three comparative test methods,including oblique bolt reverse shear,oblique bolt forward shear,and no oblique bolt shear,were used to analyze the failure state of the segment joints and the relative displacement of the joints.The study shows that the compressive zone height and ultimate bending moment of the concrete segment joints with or without oblique bolts both show a linear increase with the increase of axial force,while the maximum opening width and opening angle both show a linear decrease with the increase of axial force.For the segment joint with oblique bolt connections,the relative displacement curve shows a platform segment,and the platform segment under forward shear is significantly longer than that under reverse shear.Through the comparative study of the forward shear and reverse shear failure of the segment joints,the macroscopic deformation law of the bending and shear resistance of the joint can be comprehensively revealed.The research results can provide reference for the rational selection of shield tunnel segment joint construction.