| Metro which has the feature of fast-speed,high-effectivity and high-capacity,has already been the important infrastructure that solves urban traffic jam and which upgrades the city.Normally metro is under ground,and crosses the CBD which is crowded,so urban construction has the risk to destroy existing metro tunnel and therefore influence normal metro operation.The problem of how to assess the adjacent construction's influence on the safety of existing metro tunnel has been the first problem that faced by urban construction.Hangzhou City Xiaoshan District Caihong viaduct project and Xianghu Mountain tunnel project are both close to Hangzhou metro first line.This paper relies on the practice of these projects,with local investigation,the computation and theoretical analysis,to investigate the risk of building Caihong viaduct and Xianghu Mountain tunnel to the safety of Hangzhou metro first line tunnel.The contents of the research are as follow.(1)To adopt the numerical finite element method to calculate and analyze the stressed and distorted influence to Hanzhou metro#1 line tunnel.The founding of three dimensional finite element model of Xianghu Mountain tunnel's construction shows#1 line subway's first lining is a little distorted,which is to the maximum of 3.32mm.The construction of open cut tunnel's inverted arch causes the rise of metro tunnel's first lining,which is to the maximum of 3.62mm.The distortion of second lining is only to the maximum of 1.99mm.Following the standard,we has got a safe result.(2)By founding two dimensional finite element model of Caihong Avenue,we get the stressed and distorted influence of Caihong viaduct,s pile foundation construction and the influence when the bridge is loading.As a result,when the pile foundation is constructing and using,the influence to the metro tunnel is very low,the calculated distortion is to the maximum of 1.38mm,which meets the requirement.(3)Based on the numerical calculation,and risk assessment methods,then start to assess projects' designing and constructing risks of Xianghu Mountain north gate and Caihong express perspectively.By using the data collected,founds uncertainty models,and then gets risk assessment results of Xianghu Mountain tunnel and Caihong Express.As the result shows:two projects' designing and constructing risks are about medium to small.By monitoring the process of constructing,the risk will get lower,the safety may ensure.Finally,the analytic methods and engineering examples in this paper can be a reference of municipal works and assessment of metro tunnel's safety. |
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