摘要
软土地区的浅埋隧道由于土层软弱,易产生较大变形和坍塌。为解决隧道开挖时的围岩变形及开挖工法选择问题,依托紫之隧道第1标段暗挖段工程,对洞内拱顶沉降、拱腰收敛和仰拱隆起进行实测,对实测数据的规律与影响因素进行分析。研究结果表明:1)CRD工法在淤泥质软土中与四台阶法在强风化泥质粉砂岩中测得的拱顶沉降都较大;2)拆除隧道支撑会引起较大的拱顶沉降,其比例占总拱顶沉降的14.63%;3)隧道在淤泥质软土中开挖时会发生椭圆化变形,二次衬砌完成后,由于隧道基底承载力不足,隧道产生了整体沉降;4)降雨会使上部土体超载,并弱化围岩的强度,导致拱顶沉降加大;5)土质条件与施工工法的变化都会明显影响拱顶沉降,在隧道变形要求严格的区域或淤泥质软土中,采用CRD工法开挖风险仍较大。
Large deformation and collapse are easily occurred in shallow-buried tunnels due to soft soils. In order to solve the problem of surrounding rock deformation and the selection of excavation method during tunnel excavation, the crown top settlement, hance convergence and inverted arch settlement of Zizhi Tunnel are monitored; and the monitored data and influencing factors are analyzed. The results show that： （1） The crown top settlement of tunnels constructed by CRD method in mucky soft soil and that by 4-bench method in highly weathered silty siltstone are relatively large. （2） The dismantling of support will also cause large crown top settlement, which accounts for 14.63% of total crown top settlement. （3） Elliptical deformation would occur when tunnel is located in silty soft soil; and overall settlement would occur after completion of secondary lining because of insufficient bearing capacity of the tunnel base. （4） The rainfall will overload the upper soil and weaken the strength of surrounding rock, which leads to increase of crown top settlement. （5） The change of soil conditions and construction methods will affect the crown top settlement obviously; and the risk of excavation by CRD method in areas where tunnel deformation is strictly controlled or in mucky soft soil is still high.
作者
魏纲
姚王晶
许斌
石长江
傅翼
王哲
WEI Gang;YAO Wangjing;XU Bin;SHI Changjiang;FU Yi;WANG Zhe(Department of Civil Engineering,Zhejiang University City College,Hangzhou 310015,Zhejiang,China;Institute of Geotechnical Engineering,Zhejiang University of Technology,Hangzhou 310014,Zhejiang,China;China Southwest Geotechnical Investigation and Design Institute Hangzhou Branch,Hangzhou 310015,Zhejiang,China;Hangzhou City Construction Investment Group Limited,Hangzhou 310002,Zhejiang,China)
出处
《隧道建设（中英文）》
北大核心
2018年第7期1123-1130,共8页
Tunnel Construction
基金
浙江省科技厅公益技术研究项目(2016C33051)
关键词
浅埋暗挖隧道
软土
大断面
拱顶沉降
周边收敛
shallow-buried mined tunnel
soft soil
large cross-section
crown top settlement
surrounding convergence
