摘要
超浅埋大跨度双连拱隧道施工过程中围岩应力变化与衬砌荷载转化极为复杂,隧道结构安全性和围岩稳定性控制难度较大,特别是在下穿城市主干道等敏感建设环境下,选择合理的开挖方案对于保障工程顺利实施至关重要。本文依托厦门第二西通道双连拱隧道,通过数值模拟与现场监测等方法,对“对称”与“非对称”两种开挖方案下的围岩变形与结构受力进行了分析,并综合考虑围岩稳定性与结构安全性,以及施工工期等因素,确定了双连拱隧道最终开挖方案。研究表明:非对称开挖方案的围岩塑性区分布范围略大,对称与非对称开挖引起的最大地表沉降分别为20.24 mm和24.61 mm;两种方案的初支、二衬和临时支撑受力均在安全范围内,中墙最大偏压分别为2166.1 kPa和2131.2 kPa。在两种方案的围岩变形和结构受力均满足控制要求,且相差较小的前提下,考虑到施工工期和施工灵活性,双连拱隧道采用非对称开挖方案更为合理。研究结果可为城市复杂条件下双连拱隧道的设计施工提供有益参考。
Construction of twin-arch tunnel involves high risk because the stress changes and the transformation of liner loads are extremely complex.It is difficult to control the safety of tunnel structure and stability of surrounding rock.Under the sensitive construction environment such as passing through the urban street,it is essential to choose a reasonable excavation scheme to ensure the smooth implementation of the project.Based on the twin-arch tunnel of Xiamen Second Western Passage,this paper analyzed the surrounding rock deformation and structure stress of symmetrical and asymmetric excavation schemes by numerical simulation and field monitoring.The final excavation scheme of the twin-arch tunnel was determined according to the surrounding rock stability and structure safety,as well as the construction period and other factors.The results show that the zone of plastic deformation of surrounding rock in asymmetric excavation scheme is slightly larger,and the maximum ground settlement caused by symmetric and asymmetric excavation is 20.24 mm and 24.61 mm respectively;the stress of initial support,secondary liner and temporary support of the two schemes are within the safe range,and the maximum asymmetrical pressure on the central pillar is 2166.1 kPa and 2131.2 kPa respectively.On the premise that the surrounding rock deformation and structural stress of the two schemes meet the control requirements,and the difference is small,considering the construction period and construction flexibility,the asymmetric excavation scheme for twin-arch tunnel is more reasonable.The research results can provide useful reference for the design and construction of similar projects at home and abroad.
作者
王学斌
刘杨
Wang Xuebing;Liu Yang(Xiamen Road&Bridge Construction Group Co.,Ltd.,Xiamen,Fujian 361026,P.R.China;School of Rail Transportation,Soochow University,Suzhou,Jiangsu 215000,P.R.China)
出处
《地下空间与工程学报》
CSCD
北大核心
2022年第S01期243-251,共9页
Chinese Journal of Underground Space and Engineering
关键词
超大断面
双连拱隧道
开挖方案
围岩变形
结构受力
super-large cross-section
twin-arch tunnel
excavation scheme
surrounding rock deformation
structure stress
