摘要
本文从地质原因、管片接头刚度、右线施工时对左线管片受力影响等方面分析了某地铁管片在使用中的开裂原因,并利用数值方法分析了管片接头刚度变化和右线施工时对左线管片受力的影响。分析结果表明:管片接头处的连接块和封顶块变形不相等,封顶块的变形比连接块的大,当外荷载增加时,连接块会承担更多的荷载,如果超过其开裂荷载就会产生裂缝;后施工的右线盾构掘进过程对先施工的左线隧道管片受力也有影响,后施工隧道所产生塌落拱拱脚作用在临近既有隧道斜上方,会引起既有线路管片环向拉应力发生改变。综合分析地质原因、管片接头刚度、右线施工时对左线管片受力影响,找到了裂缝隔片产生在连接块上的原因。研究成果对管片隧道工程在设计和施工中预防裂缝出现具有一定的指导意义,可为类似工程提供借鉴。
The cracking reasons of the segments of an urban metro in use are analyzed from aspects of geological causes,stiffness of segment joints and influences of the right lane on the left segment during construction.Simulation is used to analyze the influences of segments on the force caused by the change of segment stiffness and the influences of the right lane construction on the left segments.It is found that the deformation of connection block and cap block is not equal at the segment joint.When the external load increases,the connection block will bear higher load and then cracking occurs when the load reaches the critical value.Besides,the shield excavation process of the right lane will also affect the force on the excavated left lane.The foot of the slumping arch induced by the tunnel excavated afterward acts on the upper-right of the existing tunnel,making circumferential tensile stress in the existing metro change.From the comprehensive analysis of geological causes,joint stiffness,influences of the right lane to the left when the metro is under construction,the reasons for the cracking in joint blocks are found out.The research results provide guidance for researchers on crack control,tunnel design and construction,and even valuable references for similar projects.
出处
《土木工程与管理学报》
2011年第2期44-49,72,共7页
Journal of Civil Engineering and Management
关键词
盾构
封顶快
开裂
管片接头刚度
塌落拱
shield tunnel
cap block
cracking
segment joint stiffness
slumping arch
