盾构隧道钢纤维混凝土管片接头极限承载力试验  

Experimental Investigation on Ultimate Bearing Capacity of Steel Fiber Reinforced Concrete Segment Joints in Shield Tunnels

作　　者：龚琛杰 丁文其[1,2] 

机构地区：[1]同济大学地下建筑与工程系,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

出　　处：《中国公路学报》2017年第8期134-142,共9页China Journal of Highway and Transport

基　　金：国家自然科学基金项目(51378388);上海市科学技术委员会项目(15XD1522500;15DZ1204003)

摘　　要：针对钢纤维混凝土管片在盾构隧道工程中应用日益频繁的现状,以盾构隧道钢纤维混凝土管片接头为试验对象,采用足尺试验方法对钢纤维混凝土管片接头和传统钢筋混凝土管片接头的极限承载能力进行研究,归纳宏观破坏现象,获得了荷载-挠度曲线和弯矩-转角曲线等整体力学响应特性,得到了荷载-螺栓应变关系和荷载-混凝土表面应变等局部力学响应特性,分析了受压区剪裂缝的扩展规律,探讨了接头的延性指标,并对接头进行了基于性能的极限承载能力评价。研究结果表明:钢纤维混凝土管片接头的开裂荷载比钢筋混凝土管片接头提高12.9%;钢纤维混凝土管片接头的极限荷载与钢筋混凝土管片接头基本一致(略微增加4.4%);钢纤维混凝土管片接头具有优良的抗裂能力,受压区剪裂缝数量为1个,少于钢筋混凝土管片接头的3个,承载能力极限状态时的最大裂缝宽度从3.82mm减少到1.35mm,正常使用状态时的最大允许裂缝宽度(0.2mm)对应的荷载抗力提高了43.75%;钢纤维混凝土管片接头的受力性能优于钢筋混凝土管片接头;研究成果可为钢纤维混凝土管片在盾构隧道工程中的应用提供理论支撑和技术参考。The steel fiber reinforced concrete（SFRC）segment has been increasingly adopted in the tunnel engineering but little scientific efforts was made.To fill this knowledge gap,a fullscale test was conducted to investigate the ultimate bearing capacity of the SFRC segment joints used in shield tunnels.A traditional reinforced concrete segmental joint was tested for comparison as well.By summarizing the macro-failure state,the global mechanical response of load-deflection curves and moment-rotational angle curves together with the local mechanical response of loadbolt strain relationships and load-concrete surface strain ware discussed.The shear crack propagation was analyzed in detail.The joint ductility indexes of two segment joints were thencompared.The performance-based ultimate bearing capacity was introduced to evaluate the robustness of the tested joints.Results indicate that compared with conventional reinforced concrete（RC）segments,the cracking load of the SFRC segments increases by 12.9%,ultimate load increases by 4.4%.On account of good crack resistance of SFRC segments,the number of shear crack of decreases to 1and maximum crack width decreases from 3.82 mm to 1.35 mm in ULS.The corresponding load resistance of maximum allowable crack width（0.2 mm）in SLS increases by 43.75%.The overall mechanical performance of SFRC joint is better than that of traditional RC joint.The results in this paper can provide a theoretical and technical reference for applications of SFRC segments in tunnel engineering.

关 键 词：盾构隧道 管片接头 足尺试验 极限承载力 钢纤维混凝土 

分 类 号：U459.3[建筑科学—桥梁与隧道工程]