大断面类矩形盾构隧道管片接头极限抗剪切承载力试验研究  

Experimental study on the ultimate shear bearing capacity of segment joint in shield tunnel with large quasi-rectangular cross-section

作　　者：巩一凡 丁文其[1,2] 龚琛杰 姜弘 Gong Yifan;Ding Wenqi;Gong Chenjie;Jiang Hong(College of Civil Engineering,Tongji University,Shanghai 200092,China;Key Laboratory of Geotechnical and Underground Engineering ofthe Ministry ofEducation,Tongji University,Shanghai 200092,China;Shanghai Urban Construction Design&Research Institute(Group)Co.,Ltd.,Shanghai 200011,China)

机构地区：[1]同济大学土木工程学院,上海200092 [2]同济大学岩土及地下工程教育部重点实验室,上海200092 [3]上海城市建设设计研究总院(集团)有限公司,上海200011

出　　处：《土木工程学报》2019年第11期120-128,共9页China Civil Engineering Journal

基　　金：国家自然科学基金(51378388);上海市科委科研计划项目(15XD1522500,16DZ1201701)

摘　　要：类矩形盾构隧道具有断面利用率大、覆土浅、施工成本低等优点,在城市高密度区域具有广泛的应用前景。相较于广泛使用的圆形隧道,类矩形隧道由于自身成拱效应较差,隧道肩部接头结构易产生较大的剪切荷载,有必要对接头的剪切性能进行研究。文章以某大断面类矩形盾构隧道为原型,以混凝土管片接头为试验对象,采用足尺试验方法对其抗剪切性能进行研究,归纳宏观破坏现象,获得了剪轴比(接头剪力/轴力)-相对错台量关系等整体力学响应特性,得到了剪力-螺栓应变曲线和剪力-混凝土表面应变等局部力学响应特性,并引入数字照相分析技术(DIC)对接头结构的开裂破坏全过程进行记录,分析剪切裂缝的扩展规律,最后对结构的抗剪承载性能进行评价。基于试验数据总结了管片错台随剪轴比的"四阶段"变化规律:克服摩擦阶段(剪轴比小于0.4)、间隙闭合阶段(剪轴比为0.4~0.75)、抗剪强化阶段(剪轴比为0.75~2.76)、屈服破坏阶段(剪轴比大于2.76)。试验结果表明,剪切荷载作用下该断面形式的大断面类矩形盾构隧道接头抗剪切屈服剪轴比为2.76,具有较好的抗剪切承载性能。研究成果可以为类似类矩形盾构隧道工程提供理论支撑和技术参考。The quasi-rectangular shield tunnel has wide application prospects in the high-density area of city,due to its advantages of large section utilization,shallow overburden and low construction cost.Compared with the widely used circular tunnels,quasi-rectangular tunnels are prone to produce large shear loads at shoulder joint structure due to their poor arching effect,so it is necessary to study the shear behavior of the joints.In this work,a full-scale test was conducted to investigate the ultimate shear capacity of the segment joint in a shield tunnel with large quasi-rectangular cross-section.By summarizing the macro-failure state,the global mechanical responses such as shear axis ratio(shear force divided by axial force)-dislocation relationships as well as the local mechanical responses such as shear axis ratio-bolt strain curves and shear axis ratio-concrete surface strain were achieved.Furthermore,digital image correlation(DIC) analyses were then introduced to record the entire cracking and failure process of the joint structure.The propagation rule of shear cracks was analyzed,and then the shear capacity of the joint was evaluated.Based on the test results,the relationship curve between the segment dislocation and the shear axis ratio appears to be four stages:the friction resistant stage(shear axis ratio is less than 0.4),the gap closure stage(shear axis ratio is in the range of 0.4~0.75),shear hardening stage(shear axis ratio is in the range of 0.75~2.76) and the yield failure stage(shear axis ratio is larger than 2.76).Test results indicate that under the shear loading,the yield shear axis ratio of the joint used in the present shield tunnel with large cross-section is 2.76,implying its good shear bearing capacity.The results in this study can be referred theoretically and technically by similar quasi-rectangular shield tunnel projects.

关 键 词：盾构隧道 接头性能 足尺试验 抗剪切性能 大断面类矩形盾构隧道 

分 类 号：U451.5[建筑科学—桥梁与隧道工程]