MONITORING AND CONTROL OF CONSTRUCTION DEFORMATION OF URBAN SHALLOW-BURIED LARGE-SPAN DOUBLE-ARCH TUNNEL UNDER COMPLEX CONDITION
LI Erbing1,WANG Di2,WANG Yuan1,TAN Yuehu1,ZHANG Linghui1(1.Engineering Institute of Engineering Corps,PLA University of Science and Technology,Nanjing,Jiangsu 210007,China;2.Nanjing Urban Construction Investment Holding(Group) Co.,Ltd.,Nanjing,Jiangsu 210009,China)
The shallow-embedded depth and dense surrounding buildings are two main characteristics of urban road tunnel.Taking the construction of Jiuhuashan Tunnel in Nanjing for example,the contents,technique and method of deformation monitoring of urban shallow-buried large-span double-arch tunnel under complex geologic condition are described in detail.The deformation of tunnel during different construction stages is monitored and analyzed;and the engineering measures to control deformation are put forward.The result shows that(1) the deformation and stability time of tunnel are closely related with the geologic conditions,and increase with the surrounding rock becoming worse.(2) the deformation of the soft ground has lagging effect;and the time effect of the deformation is more prominent than the spatial effect of the deformation.(3) the enclosure of the lining is an effective method to improve the performance of lining and to restrain the deformation of tunnel;and it′s important to construct the inverted arch and to close the lining.The experience and conclusions presented can provide reference to design,construction and research of similar tunnel.