综合管廊变形缝抗剪锚筋往复加载试验研究

Experimental study on shear anchor bars of deformation joint in utility tunnel under cyclic loading

现浇钢筋混凝土综合管廊变形缝发生变位,会使廊内连续布置管线沿纵向产生附加内力,影响管道安全。为限制综合管廊变形缝处的变位,工程采用在缝间设置抗剪锚筋。为研究综合管廊变形缝处抗剪锚筋的力学性能和抗震延性,以成都天府新区某综合管廊工程为背景,以抗剪锚筋布置方式、锚筋数量以及抗剪锚筋锚入长度为参数,通过4个整体结构缩尺模型的往复加载试验,对采用抗剪锚筋连接的综合管廊变形缝受力性能和抗震延性进行较为系统的研究,得到试件的破坏形态和破坏现象、力-位移曲线及延性系数。试验研究结果表明:综合管廊变形缝处设置的抗剪锚筋具有良好的延性和抗震性能;试验条件下的抗剪锚筋锚入长度均未出现锚固失效;试件破坏现象以抗剪锚筋断裂为主,并伴有混凝土大幅度开裂;试件的极限承载力大小与抗剪锚筋配置数量成正比;仅侧壁布置抗剪锚筋相对于四周均布置抗剪锚筋,极限承载力大小无明显变化,极限位移相对更大,延性性能相对较差。

The displacement of deformation joint of utility tunnel may cause additional force of the continuous pipeline in the utility tunnel along its longitudinal direction, affecting the safety of the pipeline.In order to limit the displacement of the deformation joint of the utility tunnel, shear anchor bars are used in the deformation joints.To study the mechanical properties and seismic ductility of the shear anchor bars of the deformation joints in the utility tunnel, the mechanical properties and seismic ductility of the deformation joints of the utility tunnel connected by shear anchor bars are systematically studied based on the cyclic loading tests of four scaled models of the entire structure, with the utility tunnel in Tianfu new area of Chengdu taken as an example and the layout, the number and the anchorage length of anchor bars taken as the input parameters.The failure mode, failure phenomenon, force-displacement curve and ductility coefficient of the specimens are then obtained.The experimental results showed that the shear anchor bars in the deformation joints of the utility tunnel had good ductility and seismic performance;under the test conditions, the shear anchor bar did not fail along its anchorage length;the failure of the specimen mainly appeared to be the breakage of the shear anchor bars, accompanied by the large-scale cracking of the concrete;the ultimate bearing capacity of the specimen was directly proportional to the number of shear anchor bars;comparing the shear anchor bars arranged only on the side walls with the ones arranged on all sides, no obvious change in the ultimate bearing capacity could be observed, but the ultimate displacement was relatively larger and the ductility was poorer.