摘要
渗漏水是隧道工程最常见病害之一,与衬砌施工缝处理质量关系密切.工程建设中,隧道衬砌纵向钢筋在环向施工缝部位是否断开一直存在争议,相关研究也较少.力学分析表明,隧道纵向钢筋主要起构造作用,在施工缝处可以断开;从约束裂缝发生机理分析,环向施工缝处设置贯通钢筋,导致施工缝两侧衬砌段收缩变形受到约束,可能诱发衬砌中部环向约束裂缝出现.现场实践表明,衬砌纵向筋在环向施工缝处连续设置会严重影响中埋式止水带和端模安装质量,影响挡头模板的拆除且损伤防水板,从施工缝防水质量角度,纵向筋应断开.研究认为,衬砌纵向筋沿环向施工缝断开,有利于减少环向约束裂缝的发生,提高环向施工缝处防水施工质量,实现衬砌收缩变形的同时施工缝"开而不漏".
Abstract
Water leakage is one of the serious diseases in tunnel engineering,and it is closely related to the treatment quality of lining construction joints.It is controversial on the disconnection of longitudinal reinforcements at the circumferential construction joint in tunnel lining during engineering construction,and there is also limited research on this topic.The mechanical analysis shows that the longitudinal reinforcements in the tunnel lining mainly serve as structural reinforcement and can be disconnected at the construction joints.From the perspective of the mechanism of constraint cracks,the continuous longitudinal reinforcements at the circumferential construction joint will restrict the shrinkage deformation of the lining segments on both sides of the joint,which may induce the occurrence of circumferential constraint cracks in the middle of the lining segment.Site practice has shown that continuous setting of longitudinal reinforcements at the circumferential joint of the lining will seriously affect the installation quality of medium-buried waterproof belts and the end formworks,as well as the removal of the formworks and damage to the waterproof board.From the perspective of the waterproof quality of the construction joint,the longitudinal reinforcements should be disconnected at the joint.The research suggests that the longitudinal reinforcements in tunnel lining should be disconnected at the circumferential joint,which will be conducive to reducing the occurrence of circumferential constraint cracks in the lining,and improving the waterproof quality at the circumferential construction joint.The construction joints of the lining keep no leakage with crack of shrinkage deformation.
维普
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